Thursday, April 09, 2009 4:45 PM

Hey peeps. Erica Maddux (PA2) gave me her PowerPoint notes from the Abdomen lecture last year.

It’s huge, obviously, so I hope it attaches okay.

It might be too much information, but maybe it explains something a little differently or something, I don’t know.

Hopefully it’ll help someone!

It’s almost the Frickin’ Weekend!

Nick RasmussenClass President

Physician Assistant Class of 2011Butler University

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Abdomen

AP 304

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Overview

• Abdominal walls– Contract to increase intra-abdominal pressure– Distend to accommodate expansion from viscera– Movement produces friction:

• Body compensates by having a peritoneum (serosa)– Serous membrane on posterior wall that reflects onto abdominal

viscera– Forms a bursal sac/lined potential space (peritoneal cavity)

» Normally just enough fluid to lubricate linings– Double layered reflection provide passage for blood vessels,

lymphatics and nerves

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• Abdominal cavity– Between thoracic diaphragm and

pelvic diaphragm– Has no floor (continuous with pelvic

cavity)• Use plane of pelvic inlet (superior

pelvic aperture)• Arbitrarily separates abdominal

and pelvic cavities

– Extends superiorly into thoracic cage to 4th intercostal space

• Protects superior abdominal organs

– Greater pelvis• Supports and protects lower

abdominal viscera

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• Clinical description of abdominal cavity– Two methods:

• 1) Use of nine regions– 4 planes: 2 sagittal and 2 transverse– Sagittal are generally midclavicular to midinguinal points– Transverse:

» Subcostal plane: inferior border of 10th costal cartilage on each side

» Transtubular plane: passing though the iliac tubercles and the body of the L5 vertebra

• 2) Four quadrants– 2 planes:

» Transumbilical plane: through umbilicus between L3 and L4

» Median plane: longitudinally

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The vertical yellow dotted lines are the mid-clavicular lines (the ones you need to know) and the upper yellow line is the transverse subcostal line, the bottom yellow line is the transtubercular plane

KNOW WHAT IS IN WHAT REGION!!!!!

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This is the more common quadrant labeling….KNOW WHAT’S in what quadrant!!!

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• Important to know what organs are located in each abdominal region or quadrant!– Right Upper Quadrant (RUQ)

• Liver (most- right upper lobe)• Gall bladder• Stomach: pylorus• Duodenum• Head of pancreas• Right kidney• Right colic (hepatic) flexure• Ascending colon• Right half of transverse colon

– Right Lower Quadrant (RLQ)• Cecum• Appendix• Most of ileum• Inferior part ascending colon• Right ovary• Right uterine tube• Right ureter• Right spermatic cord• Uterus (enlarged)• Urinary bladder (full)

– Left Upper Quadrant (LUQ)• Liver (left lobe)• Spleen• Stomach• Jejunum and proximal ileum• Pancreas (tail and body)• Left Kidney• Left colic (splenic) flexure• Transverse colon (left half)• Descending colon (superior part)

– Left Lower Quadrant (LLQ)• Sigmoid colon• Descending colon (inferior part)• Left ovary• Left uterine tube• Left ureter• Left spermatic cord• Uterus (enlarged)• Urinary bladder (full)

Anterolateral Abdominal

• Subdivisions of abdomen– Anterior, posterior, lateral

walls (flanks)– Anterolateral abdominal wall

• Indefinite boundary between anterior & lateral portions above term often used

– Bound by:• Superior = cartilage of 7th –

10th ribs & xiphoid process• Inferior = inguinal ligament &

superior margins of anterolateral aspects of pelvic girdle

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• Anterolateral abdominal wall– Skin, subcutaneous

tissue (superficial fascia)

• Fat, muscles and aponeuroses

• Deep fascia, extraperitoneal fat, parietal peritoneum

– Skin is loosly attached except at umbilicus

– Three musculotendinous layers

• Fibers of each layer run in different directions

– Similar to thorax

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• Fascia of anterolateral abdominal wall– Subcutaneous tissue

• Variable & is a major site of fat storage– Males are very susceptible to subcutaneous accumulation

here are may have disproportional amounts of fat here compared to other parts of the body

– Inferior to umbilicus:• Deepest part of subcutaneous tissue is reinforced & has two

layers:– Superficial fatty layer (Camper fascia)– Deep membranous layer (Scarpa fascia)

» Continues inferiorly into perineal region as superficial perineal fascia (Colles fascia)

– Investing fascia• Superficial, intermediate & deep layers• Cover external aspects of the three muscle layers of

anterolateral abdominal wall and their aponeuroses– Thin, and not easily separated

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– Endoabdominal fascia• Internal aspect of abdominal wall• Continuous & named according to muscle or aponeurosis it is covering

– Transversalis fascia» Lines transverse abdominal muscle

– Parietal peritoneum• Internal to transversalis fascia

– Extraperitoneal fat• Separates parietal peritoneum & transversalis fascia (sits deep, as opposed to

superficial fatty layer)

• Clinical Note:– Liposuction

• Removing subcutaneous fat using suction– Scarpa fascia & surgery

• Closing lower abdominal skin incisions include closure of this layer (must be sewn)

– Very strong• Potential space b/w scarpia fascia & deep fascia covering rectus abdominis &

external oblique muscles– Fluid may accumulate & may spread superiorly– Cannot spread inferiorly into thigh due to fascia lata (deep fascia of the thigh)

– Endoabdominal fascia & surgery• Potential space/fat-filled space provides a plane that can be opened• Surgeon can approach structures on or in anterior aspect of posterior

abdominal wall without entering membranous peritoneal sac containing abdominal viscera

– Reduced risk of contamination– Used for placing prostheses (inguinal hernia repair)

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Endoabdominal fascia

Parietal peritoneum

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• Muscles of the Anterolateral Abdominal Wall– 5 (paired) muscles (three flat and two vertical)

• Flat muscles– External oblique, Internal oblique, Transverse abdominal– Fibers of these concentric layers run in different directions

» Outer two layers run diagonal and perpendicular to each other

» Deep layer run transversely– All are continued anteriorly & medially as strong, sheet-like

aponeuroses» Between midclavicular line & midline» Form tough, aponeurotic tendinous rectus sheath

– Aponeuroses interweaves w/ opposite side & forms midline raphe = linea alba

» Extends from xiphoid process to pubic symphysis» Also weaves fibers from superficial & intermediate & deep

layers• Vertical muscles

– Rectus abdominis, Pyramidalis

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Intramuscular and intermuscular fibers exchange between the bilaminar aponeuroses of the external and internal oblique muscles.

Transverse sections of the wall superior and inferior to umbilicus show the makeup of the rectus sheath

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• Muscles of the Anterolateral Abdominal Wall

– External Oblique Muscle• Largest & most superficial of the three flat anterolateral abdominal muscles

• Fleshy part of muscle part of lateral abdominal wall w/ its aponeurosis contributing to

anterior abdominal wall

• Forms a fan-like structure with anterior fibers running more horizontal and posterior

fibers running more vertical (“hands in pockets”)

• Aponeurosis forms around mid-clavicular line medially & at the spinoumbilical line

(umbilicus to ASIS) inferiorly

– Decussate at linea alba w/ most becoming tendinous fibers of the contralateral

internal oblique

» Forms “disgastric” muscle = two-bellied muscle sharing a common central

tendon that works as a unit

» Example: Right external oblique & left internal oblique work together when

flexing & rotating to bring right shoulder toward left hip

– External oblique aponeurosis attaches inferiorly to pubic crest medial & pubic

tubercle

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Muscle Origin Insertion Nerve Supply Main action(s)

External oblique

External surfaces of 5th - 12th ribs

Linea alba, pubic tubercle, and anterior half of iliac crest

Thoracoabdominal nerves and subcostal nerve

Compress and support abdominal viscera; flex and rotate trunk

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• Muscles of the Anterolateral Abdominal Wall– External Oblique Muscle

• Inguinal ligament (Poupart ligament)– Inferior margin of thickened external oblique aponeurosis– Continuous with deep fascia of thigh– Serves as a retinaculum (retaining band) for structures

passing deep– Lateral portion provides origin for inferior parts of the two

deeper anterolateral abdominal muscles

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The three flat abdominal muscles and formation of the inguinal ligament

Aponeurosis of external oblique is cut away. Inguinal ligament is formed by aponeurotic fibers of external oblique

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• Muscles of the Anterolateral Abdominal Wall– Internal Oblique Muscle

• Intermediate of three flat abdominal muscles• Thin muscular sheet that fans out anteromedially• Fleshy fibers run perpendicular to those of the external

oblique• Becomes aponeurotic at mid-clavicular line (same area

as external oblique) & helps form rectus sheath

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Muscle Origin InsertionNerve Supply Main action(s)

Internal oblique

Thoracolumbar fascia, anterior two-thirds of iliac crest, and lateral half of inguinal ligament

Inferior borders of 10th - 12th ribs, linea alba, and pubis via conjoint

tendon

Thoracoabdominal nerves and first lumbar

nerves

Compress and support abdominal viscera; flex and rotate

trunk

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• Muscles of the Anterolateral Abdominal Wall– Transverse Abdominal Muscle

• Innermost of the three flat abdominal muscles• Circumferential orientation allows:

– Compression of abdominal contents– Increasing intra-abdominal pressure

• End in aponeurosis which contributes to rectus sheath– Neurovascular plane

• Between internal oblique & transverse abdominal muscles• Contains the nerves & arteries supplying anterolateral abdominal

wall• Anterior portion, nerves & vessels leave plane & lie in subcutaneous

tissue

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Muscle Origin Insertion Nerve Supply

Main action(s)

Transverse abdominal

Internal surfaces of 7th - 12th costal cartilages, thoracolumbar fascia, iliac crest and lateral third of inguinal ligament

Linea alba with aponeurosis of internal oblique, pubic crest, and pubis via conjoint ligament

Thoracoabdominal nerves and first lumbar nerves

Compress and support abdominal viscera

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• Muscles of the Anterolateral Abdominal Wall– Rectus Abdominis Muscle

• Broad, vertical strap-like muscle in anterior wall• Paired muscle separated by linea alba• Three times thicker inferiorly than superiorly• Most is enclosed in rectus sheath

– Rectus sheath anchored transversely by three or more tendinous intersections

» Muscular people = the sections between the intersections bulge outward

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Muscle Origin Insertion Nerve Supply

Main action(s)

Rectus abdominis

Pubic symphysis and pubic crest

Xiphoid process and 5th - 7th costal cartilages

Thoracoabdominal nerves

Flexes trunk (lumbar vertebrae) and compresses abdominal viscera; stabilizes and controls tilt of pelvis

Linea alba

Tendinous intersections: usually occur at level of xiphoid process and umbilicus, and halfway between these structures

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• Muscles of the Anterolateral Abdominal Wall– Pyramidalis

• Small triangular muscle– Anterior to inferior part of rectus

abdominis– Attaches to anterior surface of pubis &

anterior pubic ligament– Ends in linea alba

• Absent in 20% of people• Tenses the linea alba• Landmark for surgeons for an

accurate median abdominal incision

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• Rectus Sheath– Fibrous compartment of rectus abdominis & pyramidalis

muscles– Contains superior & inferior epigastric arteries & veins,

lymphatic vessels, distal portions of thoracoabdominal nerves

– Formed by decussation & interweaving of aponeuroses of the flat abdominal muscles

• External oblique aponeurosis contributes to anterior wall of sheath throughout entire length

• Internal oblique aponeurosis:– Superior 2/3 spits into two layers (lamina)

» One lamina passes anterior to rectus abdominis & joins aponeurosis of external oblique

» One lamina passes posterior to rectus abdominis & joins aponeurosis of transverse abdominal muscle

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Intramuscular and intermuscular fibers exchange between the bilaminar aponeuroses of the external and internal oblique muscles.

Transverse sections of the wall superior and inferior to umbilicus show the makeup of the rectus sheath

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• Linea Alba– Runs vertically the entire length of the anterior abdominal

wall– Separates bilateral rectus sheaths– Transmits small vessels and nerves to the skin

• Umbilical ring– Middle of linea alba, underlying umbilicus– Defect in linea alba through which fetal umbilical vessels

passed to & from umbilical cord– All layers of anterolateral abdominal wall fuse at umbilicus

• Postnatally: fat accumulates in subcutaneous tissue & skin becomes raised around umbilical ring & umbilicus becomes depressed

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• Functions & actions of the anterolateral abdominal muscles– Strong, expandable support for the anterolateral abdominal wall

• Contraction of diaphragm anterolateral muscles relax to make room for the organs

– Protect the abdominal viscera from injury– Compress the abdominal contents to maintain or increase intra-

abdominal pressure & oppose the diaphragm• Elevates the relaxed diaphragm to expel air during respiration

– Coughing, sneezing, nose blowing, yelling• Provides force for defecation, micturation, vomiting, parturition• Involved with heavy lifting

– Move the trunk and help maintain posture• Powerful flexion of thoracic and lumbar regions of vertebral

column

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• Clinical Note:– Palpation of the anterolateral abdominal wall

• Guarding– Involuntary spasms of the muscles– When an organ is inflamed or injured the body/abdomen produces

intense guarding» Board-like reflexive muscular rigidity that cannot be willfully

suppressed» Clinically significant sign of acute abdomen

– Goal is to protect viscera from pressure– Due to common nerve supply of skin and muscles of the wall

– Superficial abdominal reflexes• Abdominal wall in the only protection most of the abdominal

organs have• Quickly stroking horizontally (lateral to medial) toward umbilicus

produces a contraction of the abdominal muscles

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• Clinical Note:– Protuberance of the abdomen

• Normal in infants and young children– Increase amount of air in GI tract– Muscles gaining strength– Large liver

– Six common causes of protrusion:• Food, fluid, fat, feces, flatus (air distention), fetus

– Eversion of umbilicus may be sign of increased intra-abdominal pressure (ascites)

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• Clinical Note:– Hernias

• Umbilical hernias– Common in newborns

» Weak anterior abdominal wall in umbilical ring– Small and result from increased intra-abdominal pressure in

presence of weakness and incomplete closure of anterior abdominal wall

– Occurs through umbilical ring• Acquired umbilical hernia

– Most common in women and obese people• Epigastric hernia

– Hernia in epigastric region through linea alba occurs in midline

• Spigelian hernia– Occur along semilunar lines

Nerves of the Anterolateral Abdominal Wall

• Nerve distribution– Peripheral nerve distribution is virtually identical to the dermatome

map of the anterolateral wall• Anterior rami of spinal nerves (T7-T11) do not participate in plexus

formation– L1 bifurcates into two peripheral nerves (exception)

– Dermatome• Posterior overlying intervertebral foramen, follows slope of ribs around

the trunk– T10 includes umbilicus– L1 includes inguinal fold

– Anterolateral abdominal wall supplied by:• Thoracoabdominal nerves (from the costocartilage nerves)• Lateral (thoracic) cutaneous branches• Subcostal nerve

– Anterior rami of T12• Iliohypogastric & ilioinguinal nerves

– Terminal branches of anterior rami of L136

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• Anterolateral abdominal wall nerves– Thoracoabdominal nerves

• Abdominal (distal) parts of anterior rami of the inferior six thoracic spinal nerves T7-T11 – intercostal nerves but distal to costal margin

• Pass inferoanteriorly from intercostal space and run in neurovascular plane

– Between internal oblique and transverse abdominal muscles– Lateral cutaneous branches

• Of the thoracic spinal nerves (T7-T9 or T10)• Emerge from musculature of anterolateral wall to enter

subcutaneous tissue along anterior axillary line– Anterior abdominal cutaneous branches pierce rectus sheath

» T7 – T9 supply skin superior to umbilicus» T10 innervates the skin around the umbilicus» T11 plus cutaneous branches of subcostal, iliohypogastric,

ilioinguinal supply skin inferior to umbilicus

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See table 2.2 (nerves of anterolateral abdominal wall)

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• Clinical Note:– Injury to Nerves of Anterolateral abdominal wall

• Inferior thoracic spinal nerves (T7-T12) and iliohypogastric / ilioinguinal nerves (L1)

– Enter abdomen muscles separately and provide multi-segmental innervation of abdominal muscles

– Distributed across anterolateral abdominal wall in a horizontal to oblique course

» Susceptible to injury from trauma or surgery at any level of wall

» Causes weakness of muscles and may predispose individuals to the development of an inguinal hernia

Vessels of the Anterolateral Abdominal Wall

• Skin and subcutaneous tissues– Intricate subcutaneous venous

plexus• Drains superiorly to internal

thoracic vein• Drains laterally to medial and

lateral thoracic vein• Drains inferiorly to epigastric

veins– Parumbilical veins

• Small tributaries of portal vein• Parallel obliterated umbilical

vein (round ligament of the liver)– Thoracoepigastric vein

• Exist or develop between superficial epigastric vein and lateral thoracic vein

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• Four primary blood vessels (artery and veins) of the anterolateral abdominal wall– Superior epigastric vessels &

musculophrenic arteries• From internal thoracic

vessels– Inferior epigastric & deep

circumflex iliac vessels• From external iliac vessels

– Superficial circumflex iliac & superficial epigastric vessels

• From femoral artery and greater saphenous veins respectively

– Posterior intercostal vessels• Of 11th intercostal space and

anterior branches of subcostal vessels

Fig 2.6

• Four primary blood vessels– Superior epigastric artery

• Direct continuation of internal thoracic artery

• Supplies superior part of rectus abdominis and anastomoses with inferior epigastric artery in umbilical region

– See table 2.3

– Inferior epigastric artery• From external iliac artery just

superior to inguinal ligament• Runs superiorly in

transversalis fascia• Enters lower rectus

abdominis and anastomoses with superior epigastric artery

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Table 2.3

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• Lymphatic drainage of anterolateral abdominal wall– Superficial lymphatic vessels

• Accompany subcutaneous veins

• Superior to transumbilical plane

– Drain primarily to axillary lymph nodes with a few draining to parasternal lymph nodes

• Inferior to transumbilical plane

– Drain to superficial inguinal lymph nodes

– Deep lymphatic vessels• Accompany deep veins of

abdominal wall– Drain to external iliac,

common iliac and right and left lumbar lymph nodes

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• Clinical Note:– Abdominal surgical incisions

• When possible should follow cleavage lines– Should allow adequate exposure, and best cosmetic effect– Location depends on type of operation, location of organs, avoidance

of nerves, maintaining blood supply and minimizing injury to muscles and fascia

» Must consider direction of muscle fibers, location of aponeuroses and nerves

• Do not transect muscles– Causes irreversible necrosis– Better to split them in direction of their fibers– Exception:

» Rectus abdominis: short fibers run between tendinous intersections and has segmental innervation that enters at lateral part of rectus sheath

• Muscles and viscera are retracted toward, not away from their neurovascular supply

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• Clinical Note:– Abdominal surgical incisions

• Longitudinal Incisions– Primarily used centrally in abdomen (muscle and vasculature are

longitudinal)– Median or midline incisions

» Can be made rapidly without cutting muscle, major blood vessels or nerves

» Cut through linea alba: only small blood vessels and nerves to skin (less bleeding)

» But…poor blood supply may have necrosis of edges are not aligned properly during closure

» May have large amount of vascularized fat– Paramedian incision

» Made in the sagittal plane & may extend from costal margin to public hairline

» Once through rectus sheath muscle is retracted laterally

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• Clinical Note:– Abdominal surgical incisions

• Oblique & transverse incisions– Most common on one side of midline in more peripheral abdomen– Direction is related to muscle fiber orientation– Gridiron (muscle splitting) & McBurney incisions

» Most often used for appendectomy» External oblique aponeurosis is incised inferomedially in

direction of its fibers and retracted» musculoaponeurotic fibers of internal oblique and transverse

abdominal are then split in line of their fibers and retracted.» Iliohypogastric nerve is identified and preserved» These incisions should not cut any musculoaponeurotic fibers so

abdominal wall remains strong» Gridiron is most popular and provides good access and avoids

cutting, tearing, and stretching of nerves

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• Clinical Note:– Abdominal surgical incisions

• Oblique and transverse incisions– Suprapubic (Pfannenstiel) incisions (bikini cut)

» Made at pubic hairline» Horizontal with slight convexity and are used for most gynecological and

obstetric operations» Linea alba and anterior layers of rectus sheaths are transected and

resected superiorly, rectus muscles are retracted laterally» Iliohypogastric and ilioinguinal nerves are identified and preserved

– Incisional hernia• Protrusion of omentum or an organ through a surgical incision• Muscular or aponeurotic layers of abdomen do not heal properly

– Factors such as age, obesity, infection all can increase chances

– Endoscopic surgery• Decreased risk for nerve injury, incisional hernia, and decreased healing

time

Internal Surface of Anterolateral Abdominal Wall

• Posterior (internal) surface (infraumbilical parts)– Covered with transversalis fascia, extraperintoneal fat,

parietal peritoneum– 5 umbilical peritoneal folds (make passageway for special structures):

• Median umbilical fold– Apex of bladder to umbilicus and covers median umbilical ligament

» Joined fetal bladder to umbilicus• Two medial umbilical folds

– Cover medial umbilical ligaments» Occluded parts of umbilical arteries

• Two lateral umbilical folds– Cover inferior epigastric vessels (bleed if cut)

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• Posterior (internal) surface– Peritoneal fossae– Depressions lateral to umbilical folds – sites of hernias

• Supravesical fossa– Between median and medial umbilical folds

• Medial inguinal fossa– Between medial and lateral umbilical folds– Called inguinal triangles (Hasselbach triangles)– Potential sites for direct inguinal hernia

• Lateral inguinal fossa– Lateral to lateral umbilical fold– Includes deep inguinal ring– Potential site for most common hernia in lower abdomen –

indirect inguinal hernia– Supraumbilical part

• Falciform ligament– Extends between superior abdominal wall and liver– Encloses the round ligament of the liver & paraumbilical veins

» Remnant of umbilical vein» Prenatally extends from umbilicus to liver prenatally

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Inguinal region

• Inguinal region (groin)– Area b/t anterior superior iliac spine (ASIS) and

pubic tubercle– Very Important region:

• Anatomically due to region where structures exit and enter abdominal cavity

• Clinically due to potential site of herniation– Majority of abdominal hernias occur in this region

» Inguinal hernia account for about 75% of all abdominal hernias

» Most are in men (~86%) due to passage of spermatic cord through inguinal canal

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• Inguinal ligament and iliopubic tract– Extend from ASIS to pubic tubercle– Form a bilaminar anterior (flexor) retinaculum of the hip

joint– Recall retinacula retain structures against skeleton during various

positions of the joints• This retinaculum spans subinguinal space

– Hip flexors, nerves for lower limb travel here– Inguinal ligament

• Dense band of inferiormost part of external oblique aponeurosis• Most fibers pass to pubic tubercle but some:

– Attach to superior pubic ramus & form lacunar ligament (of Gimbernat)

» medial boundary of subinguinal space– Attach run along pecten pubis as pectineal ligament (of Cooper)– Attach upward and bypass pubic tubercle and cross linea alba to

blend with lower fibers of contralateral external oblique aponeurosis» This forms the reflected inguinal ligament

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• Iliopubic tract– Thickened inferior margin of transversalis fascia and

appears as fibrous band running parallel and deep to inguinal ligament

• Seen in place when inguinal region is viewed from internal (posterior) aspect – during laparoscopy

– Reinforces posterior wall and floor of inguinal canal• Myopectineal orifice

– Inguinal ligament and iliopubic tract span this innate area of weakness

– Site of groin hernias• Indirect, direct, femoral

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Inguinal ligament is thickened, underturned, inferior margin of the aponeurosis of the external oblique, forming a retinaculum that bridges the subinguinal space

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• Inguinal Canal– Formed in relation to descent of the testis during fetal

development– Oblique passage about 4 cm long

• Inferomedial direction through inferior part of anterolateral abdominal wall

– Contents:• Male = spermatic cord• Female = round ligament of the uterus• Also contains ilioinguinal nerve, blood and lymphatic vessels

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• Inguinal Canal– Opening at both ends:

• Deep (internal) inguinal ring– Internal entrance to inguinal canal– Beginning of evagination in transversalis fascia where ductus

deferens/testicular vessels (or round ligament of the uterus) pass to enter the inguinal canal

» Fascia continues into canal and forms innermost covering (internal fascia) of the structures in the canal

• Superficial (external) inguinal ring– Exit where spermatic cord (round ligament) emerges from inguinal

canal» Lateral crus = attach to pubic tubercle» Medial crus = attach to pubic crest» Intercrural fibers = prevent crura from spreading apart

59This thing is heavily reinforced!!!

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Muscular contraction that increases intra-abdominal pressure causes roof of the canal to descend, narrowing the canal as it simultaneously collapsed anteroposteriorly by increased internal pressure

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• Descent of the Gonads– Fetal testes

• Descend from dorsal (posterior) abdominal wall in superior lumbar region to deep inguinal rings during 9th-12th fetal weeks

• Probably due to growth of vertebral column and pelvis• Male gubernaculum = attached to caudal pole of testis and is

accompanied by peritoneum, process vaginalis; the guiding tether• Testis descend posterior to process vaginalis• Inferior remnant of process vaginalis forms tunica vaginalis covering

the testis– Fetal ovaries

• Also descend from dorsal abdominal wall in superior lumbar region during 12th week but pass into lesser pelvis

• Female gubernaculum attaches to caudal pole of ovary and projects into the labia majora

– Attaches to uterus while en route and forms ovarian ligament– Remainder becomes round ligament of the uterus

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7-week embryo testis has not yet descended from posterior abdominal wall. A fetus at 28 weeks shows the processus vaginalis and the testis passing through the inguinal canal. The process vaginalis carries fascial layers of the abdominal wall. The testis passes posterior to the process vaginalis not through it. Bottom picture: In a newborn, obliteration of the stalk of the processus vaginalis has occurred. The remains have formed the tunica vaginalis and the remnant of the gubernaculum has formed the scrotal ligament

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The undifferentiated gonads at 2 months are located on the dorsal abdominal wall. The ovaries at 15 weeks have descended into the greater pelvis. The gubernaculum has become the ovarian ligament and round ligament of the uterus. The round ligament passes through the canal and attaches to the subcutaneous tissue of the labia majora. In the picture to the right (mature female) the processus vaginalis has degenerated but the round ligament and ilioinguinal nerve pass through the inguinal canal

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• Spermatic Cord– Contains structures traveling to and from testis– Begins at deep inguinal ring, passes through inguinal ring

and exits at superficial inguinal ring, finally ends in scrotum

– Fascia coverings are from anterolateral abdominal wall and surround spermatic cord (during prenatal development) and include:

• Internal spermatic fascia = from transversalis fascia• Cremasteric fascia = from fascia of both superficial and deep

surfaces of internal oblique muscle• External spermatic fascia = from external oblique aponeurosis and

its investing fascia

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• Spermatic cord (fascia)– Cremasteric fascia

• Contains loops of cremaster muscle– Formed by lowermost fascicles of internal oblique muscle

(striated) so has somatic innervation– Draws testis superiorly in the scrotum

» Regulate temperature for spermatogenesis– Innervated by genital branch of genitofemoral nerve (L1, L2)

– Dartos muscle (and fascia)– Smooth muscle of fat-free subcutaneous tissue of scrotum

(dartos fascia)» Inserts into skin and produces contraction of the skin in

the scrotum (testicular elevation also)» Smooth muscle so has autonomic innervation» Work together w/ cremaster for temp. control

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• Contents of spermatic cord– Ductus deferens (vas deferens)

• Muscular tube that conveys sperm from epididymis to ejaculatory duct– Testicular artery

• From aorta (this artery got “dragged along for the ride) & supplies testis & epididymis

– Artery of the ductus deferens• From inferior vesical artery

– Cremasteric artery• From inferior epigastric artery

– Pampiniform venous plexus• Network of veins that converge superiorly as right or left testicular veins

– Sympathetic nerve fibers• On arteries & parasympathetic nerves fibers on ductus deferens

– Have to have sympathetic & parasympathetic innervation so it can “point & shoot”– Genital branch of genitofemoral nerve

• Supplies the cremasteric muscle– Lymphatic vessels

• Drain testis & other associated structures– Vestige of process vaginalis

• Fibrous thread in anterior part of spermatic cord between abdominal peritoneum & tunica vaginalis

68Course of testicular artery (from aorta) results from descent of fetal testis from posterior abdominal wall into the scrotum. Lymph drainage from testis and scrotum follow different courses. Anterior innervation from lumbar plexus and posterior innervation from sacral plexus

See B2.1 pg 136• Clinical Note:

– Inguinal hernia• Protrusion of parietal peritoneum & viscera through a normal or

abnormal opening from the cavity in which they belong• Most are reducible (can be fixed)• 80% - 90% of abdominal hernias are in inguinal region

– Two primary types are direct & indirect hernias– Complete indirect inguinal hernia

• Normally process vaginalis obliterates before birth (except for distal part that forms tunica vaginalis)

– Peritoneal part of hernia sac is formed by this– If entire stalk of above persist, the hernia extends into the scrotum

superior to testis– The canal is intact!!

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Both direct & indirect hernia’s come out of the external inguinal ring-Indirect: canal is intact…hernia travels through the canal itself-Direct: canal is not intact…hernia breaks through the side of the inguinal canal

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Direct hernia = herniating bowel passes MEDIAL to inferior epigastric vessels. Pushing through peritoneum and transversalis fascia in inguinal triangle to enter inguinal canal

-Passes through the Hesselbach triangle

Indirect hernia = herniating bowel passes LATERAL to inferior epigastric vessels to enter deep inguinal ring

Hesselbach triangle

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• Clinical Note:– Inguinal hernia continued

• Superficial inguinal ring is palpable superolateral to pubic tubercle

• Invaginate skin of upper scrotum with index finger

• Follows spermatic cord superlaterally to superficial inguinal ring

– If hernia = sudden impulse is felt against finger when patient coughs (bears down)

– Cannot distinguish type as both hernia types exit superficial ring

– Deep inguinal ring may be palpated as a skin depression above inguinal ligament = indirect hernia

– Direct hernia palpated by finger over inguinal triangle and having person bear down and feeling for impulse

If you are at the superficial ring of the inguinal canal, you can’t tell what kind of hernia it is; you have to get your finger all of the way up there (in the inguinal canal) to be able to tell OR you can palpate medial & laterally to the inferior epigastric artery

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Most likely an indirect inguinal hernia, b/c you can see it begins laterally- Babies (male) typically have indirect hernias

Most likely a direct hernia-Adult males lift weights & can tear their inguinal canal direct hernia

History of the male can greatly help with the clinical diagnosis- Babies = indirect; adults = direct

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• Clinical Note:– Cremasteric Reflex

• Lightly stroke skin on medial aspect of upper thigh• Ilioinguinal nerve supplies area and will have a rapid elevation of testis

on same side– Hydrocele

• Excess fluid in a persistent process vaginalis– Congenital problem and is associated with an indirect hernia– Fluid from abnormal amount of serous fluid from visceral layer of

tunica vaginalis• Hydrocele of the testis is confined to the scrotum and distends the tunica

vaginalis• Hydrocele of the cord is confined to the spermatic cord• Detection requires transillumination

– Red glow indicates excessive serous fluid in the scrotum– Hematocele

• Collection of blood in tunica vaginalis• From trauma to testis and may result in scrotal and/or testicular

hematoma• Blood does not transilluminate

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You can get a hydrocele anywhere along the cord

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• Clinical Note:– Torsion of the Spermatic Cord

• Surgical emergency to prevent death of the testicle

• Torsion obstructs venous drainage which causes edema. This causes subsequent arterial obstruction and leads to necrosis of entire testicle

• Most common during adolescence

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• Scrotum– Cutaneous sac with two layers, pigmented skin, & dartos fascia

• Dartos fascia = fat-free fascial layer that includes smooth muscle fibers (dartos muscle)

– Responsible for wrinkles of scrotum– Contraction causes increase wrinkling which all reduce heat loss:

» Thickens integumentary layer» Reduces scrotal surface area» Assist cremaster muscles in holding testicles closer to the body

– Continuous anteriorly with membranous layer of subcutaneous tissue of the abdomen (Scarpa fascia)

– Continuous posteriorly with membranous layer of subcutaneous tissue of the perineum (Colles fascia)

– Divided internally by continuation of dartos fascia = septum of the scrotum

• Demarcated externally by scrotal raphe

Testicular cancer drains up (via lymphatics), but scrotum & penis drain down…this all has to do with origin (testes began above umbilicus, so drain above umbilicus

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• Scrotum– Arterial supply: they are all local

• Posterior scrotal branches of the perineal artery– Branch of internal pudendal artery

• Anterior scrotal branches of the deep external pudendal artery– Branch of femoral artery

• Cremasteric artery– Branch of inferior epigastric artery

– Venous drainage• Scrotal veins accompany the arteries (same names)

– Lymphatic vessels• Drain into superficial inguinal lymph nodes

– Nerves• Branches of lumbar plexus to anterior surface

– Genital branch of the genitofemoral nerve (L1, L2)» Supply anterolateral surface

– Anterior scrotal nerves» Branches of ilioinguinal nerve (L1) supplying anterior surface

• Branches of sacral plexus to posterior and inferior surface– Posterior scrotal nerves

» Branches of perineal branch of pudendal nerve (S2-S4) supplying posterior surface

– Perineal branches of posterior femoral cutaneous nerve (S2, S3)» Supply inferior surface

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• Testis– Male gonads that produce sperm & male hormones– Suspended in scrotum by spermatic cord

• Left testis hangs lower than right (usually)– Tunica albuginea

• Tough fibrous outer surface that thickens into ridge on internal posterior surface = mediastinum of the testis

– This ridge forms fibrous septa that extend inward between lobules of the coiled seminiferous tubules

» Seminiferous tubules are jointed by straight tubules to the rete testis

– Tunica vaginalis• Surface of each testis covered by the visceral layer of tunica vaginalis

(except where testis joins epididymis)• Closed peritoneal sac that surrounds testis and is from embryonic

processus vaginalis– Testicular arteries

• From abdominal aorta and pass retroperitoneally in oblique direction• Reach and travel through inguinal canal to supply testes

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• Testis– Pampiniform venous plexus

• Network of 8-12 veins that surround the testicular artery in the spermatic cord

• Part of the thermoregulatory system of the testis

• Veins of each plexus converge superiorly to form right testicular vein that enters IVC & left testicular vein that enters left renal vein

– Lymphatic drainage• Follows testicular artery and vein to right and

left lumbar (caval/aortic) and preaortic lymph nodes; common line: it drains deep into the upper abdominal cavity

– Autonomic nerves• From testicular plexus of nerves on testicular

artery• Contains vagal parasympathetic & visceral

afferent fibers & sympathetic fibers from T7 segment of the spinal cord

See fig 2.8

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• Clinical Note:– Spermatocele

• Retention cyst (collection of fluid) in epididymis

• Usually near its head• Contain milky fluid and

are usually asymptomatic

– Epididymal cyst• Collection of fluid

anywhere in the epididymis

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• Clinical Note:– Cancer of the Testis & Scrotum

• Lymphatic metastasis is common to all testicular tumors• Testes develop from posterior abdominal wall so lymphatic

drainage is very different from the scrotum (out-pouch of anterolateral abdominal wall)

• Cancer of testis– Metastasizes to retroperitoneal lumbar lymph nodes which

are just below renal veins & subsequent spread may be to mediastinal & supraclavicular nodes

– Metastasis may occur by hematogenous spread to lungs, liver, brain, and bone

• Cancer of the scrotum– Metastasizes to superficial inguinal lymph nodes

Peritoneum and Peritoneal Cavity• Peritoneum

– Continuous slippery transparent serous membrane– Lines abdominopelvic cavity & invest the viscera– Has two continuous layers:

• Parietal peritoneum– Lines internal surface of abdominopelvic wall– Same blood, lymphatic and nerve supply as the region of the

wall it lines» Sensitive to pressure, pain, heat/cold, and laceration» Pain is well localized

• Visceral peritoneum– Invest viscera– Same blood, lymphatic and nerve supply as viscera it invest

» Insensitive to touch, heat/cold, and laceration» Pain is poorly localized and is often referred to

dermatomes of spinal ganglia that provide sensory fibers85

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• Peritoneum– Peritoneum and viscera in abdominopelvic cavity

• Intraperitoneal organs– Almost completely covered with visceral peritoneum

» Does not mean inside peritoneum, but rather invaginated into closed sac (fist and balloon)

– Extraperitoneal organs (retroperitoneal, subperitoneal)» Outside the peritoneal cavity» Only partly covered with peritoneum (just one surface)

– Peritoneal cavity• Within abdominal cavity and continues inferior into pelvic cavity• Potential space between parietal and visceral layers

– Contains no organs– Has thin film of peritoneal fluid composed of water, electrolytes– Peritoneal fluid lubricates the peritoneal surfaces and enable the

viscera to move over each other without friction (digestion)» Contains leukocytes and antibodies (b/c G.I. tract = external

environment)• Completely closed in males, but open (to exterior of body) in females

through uterine tubes, uterine cavity, vagina– Potential site of infection

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• Clinical Note:– Surgical procedures

• Peritoneum is well innervated & patients undergoing abdominal surgery have more pain with larger incisions

• Covering of peritoneum (clinically known as serosa)– Makes watertight end-to-end anastomoses of intraperitoneal

organs» Every effort should be made to remain outside the

peritoneal cavity when possible

Generalized vs. point specific: • Specific = pushing on peritoneum @ one particular point•Generalized overall agitation

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• Clinical Note:– Peritonitis

• When there is infection, inflammation in the peritoneal cavity– Can be gas, fecal matter, bacteria– Get pain in overlying skin and increase abdominal muscle tone

• Generalized– Very dangerous and potentially lethal– May be from infection, or ruptured ulcer

– Ascites (ascitic fluid)• Excess fluid in peritoneal cavity (usually associated w/ the liver,

but not pathopneumonic)– Can be from injury, portal hypertension, infection, starvation, cancer

» Causes distention of the peritoneal cavity with several liters of abnormal fluid which may interfere with movements of the viscera

– Paracentesis (abdominal)• Treatment of general peritonitis includes removal of ascitic fluid• Paracentesis is surgical puncture of the peritoneal cavity for

aspiration/drainage

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• Clinical Note:– Peritoneal adhesions

• Any injury to peritoneum results in collection of fibrin which gets replaced with fibrous tissue

• This scar tissue forms abnormal attachments between visceral peritoneum of adjacent viscera or between viscera peritoneum and abdominal wall

– May result in outcomes such as intestinal obstruction which may wrap around adhesion (volvulus)

– Adhesions we can no longer move things like we need/want = why they sometimes have to be removed

– Peritoneal injection and dialysis• Peritoneum is semipermeable membrane with extensive surface

area that overlies blood and lymphatic capillary beds– Fluid injected is absorbed rapidly (intraperitoneal (IP) injection

• Dialysis = dilute sterile solution into cavity then drain on other side– Diffusible solutes and water are transferred between blood and

peritoneal cavity as result of concentration gradient between the two compartments

Peritoneal Formations• Mesentery

– Double layer of peritoneum– Results from invagination of peritoneum by an organ– Continuity of visceral and parietal peritoneum– Provides a means for neurovascular communication

between organ and body wall– Connects intraperitoneal organ to body wall (usually

posterior wall)– Often “mesentery” refers to small intestine mesentery

• “Meso” = mesentery at other locations– Transverse mesocolon, sigmoid mesocolon, mesoappendix

– Core of connective tissue that contain blood and lymph vessels/nodes, nerves, and fat

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Peritoneum (from physiology class)

• Why needed?– Stomach and intestines undergo strenuous contractions in

processing food and need the freedom to move• Not tightly bound to abdominal wall but loosely suspended by

connective tissue = mesenteries

• Mesenteries– Hold abdominal viscera in place and prevent small

intestine from becoming twisted• By change in body position• By contractions in digestion in food

– Passage for blood vessels, nerves, lymphatics

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Mesentery and Mesocolon

• Mesentery of small intestines holds many blood vessels• Mesocolon anchors colon to posterior body wall 93

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• Omentum– Double-layer extensions/folds of peritoneum that

pass from stomach and proximal part of duodenum to adjacent organs in abdominal cavity

• Greater omentum– Prominent fold that hangs like an apron from greater

curvature of stomach and proximal part of duodenum– Folds back and attaches to anterior surface of transverse

colon and its mesentery• Lesser omentum

– Connects lesser curvature of the stomach and proximal part of duodenum to liver

– Connects stomach to triad of structures that run between duodenum and liver in free edge of lesser omentum

Lesser and Greater Omentum

• Lesser - attaches stomach to liver• Greater - covers small intestines like an apron 95

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• Peritoneal ligament– Double layer of peritoneum that connects an organ with

another organ or to the abdominal wall– Liver

• Falciform ligament– connects to anterior abdominal wall

• Hepatogastric ligament (portion of lesser omentum)– connects to stomach

• Hepatoduodenal ligament (thick free edge of lesser omentum)– Conducts portal triad (portal vein, hepatic artery, and bile duct)

– Stomach• Gastrophrenic ligament

– Connects to inferior surface of diaphragm• Gastrosplenic ligament

– Connects to spleen• Gastrocolic ligament (apron-like part of greater omentum)

– Connects to transverse colon

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• Peritoneum continued– Bare areas

• Intraperitoneal organs are covered almost entirely by peritoneum, but this an area where there is none (no peritoneum)

– Allows entrance and exit of neurovascular structures

– Peritoneal fold• Reflection of peritoneum raised from body wall by underlying

blood vessels and ducts– May bleed if cut

– Peritoneal recess• Pouch of peritoneum that is formed by a peritoneal fold

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• Clinical Note:– Greater omentum

• Prevents visceral peritoneum from adhering to parietal peritoneum• Often forms adhesions adjacent to inflamed areas often walling it off

– May find greater omentum displaced from “normal” position• Also cushions abdominal organs against trauma and insulation

– Abscess formation• Perforation of gallbladder, appendix, ulcer may lead to formation of

circumscribed collection of pus in subphrenic recess– May be walled inferiorly by adhesions

– Spread of pathologic fluids• Peritoneal recesses are clinically important due to spread of pathological

fluids• Determine the extent and direction of the spread

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• Subdivisions of the peritoneal cavity– Divided into greater sac and an omental bursa

• Greater sac– Main and larger part of peritoneal cavity– Surgical incision through anterolateral abdominal wall enters the

greater sac• Omental bursa (lesser sac)

– Smaller part of peritoneal cavity– Lies posterior to stomach, lesser omentum, and adjacent structures– Permits free movement of the stomach on adjacent structures– Has two recesses:

» Superior recess» Inferior recess

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• Omental bursa– Inferior recess

• Potential space that is sealed off from main part of omental bursa

• Communicates with greater sac through omental foramen (epiploic foramen)

– Posterior to free edge of lesser omentum and forms hepatoduodenal ligament

– Transverse mesocolon• Divides abdominal cavity

into:– Supracolic compartment

» Stomach, liver, spleen

– Infracolic compartment» Small intestine,

ascending and descending colon

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Abdominal Viscera• Viscera of abdomen:

– Terminal part of esophagus, esophagus, stomach, intestines, spleen, pancreas, liver, gallbladder, kidneys, suprarenal (adrenal) glands

– Liver, stomach, and spleen• Fill domes of diaphragm so protected by lower thoracic cage• Falciform ligament

– Attaches along continuous line to anterior abdominal wall and divides liver superficially into right and left lobes

– Greater omentum• Conceals almost all of the intestine

– Gall bladder• Projects inferior to sharp border of the liver

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Some abdominal organs extend superiorly into thoracic cage. Large portion of small intestine is in pelvis.

Picture to right shows gallbladder, falciform ligament (severed)

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• Viscera of abdomen– Alimentary (digestive) tract

• Food passes from mouth and pharynx though esophagus to stomach

• Peristalsis– Ring-like contractions that begin around

middle of stomach and move slowly toward pylorus

• Small intestine– Primary site of absorption– Consist of duodenum, jejunum, ileum

» Stomach is continuous with duodenum and duodenum receives openings of the ducts from the pancreas and liver

• Large intestine– Cecum, appendix, colon (ascending,

transverse, descending, and sigmoid), rectum, anal canal

– Most reabsorption of water occurs in ascending colon

– Feces forms in descending and sigmoid colon and accumulate in rectum

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• Alimentary tract– Arterial supply:

• From abdominal aorta with three major branches– Celiac trunk (supplies foregut –”before the gut”- stuff)– Superior (midgut) & inferior mesenteric arteries (hindgut)

– Portal vein• Formed by union of:

– Superior mesenteric & splenic veins

• Main channel of portal venous system– Collects poorly oxygenated, nutrient rich blood from abdominal part

of alimentary tract, pancreas, spleen, most of gallbladder and caries it to liver

The portal system goes to the liver for 1st pass effect-The portal vein GOES TO THE LIVER!!!!

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108

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• Esophagus– Muscular tube about 25cm (10in) long with average

diameter of 2cm– Extends from pharynx to stomach– Follows vertebral column as it descends through neck and

mediastinum– Passes through esophageal hiatus in diaphragm at level of

T10 vertebrae– Terminates at esophagogastric junction

• Where contents enter stomach• Left of midline at level of T11

– Retroperitoneal– Circular and external longitudinal layers of muscle

• Superior third external layer is voluntary striated muscle• Inferior third is smooth involuntary muscle• Middle third is mixture of the two types of muscle

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• Esophagus – Esophagogastric junction

• Marked by abrupt transition from esophageal to gastric mucosa = clinically known as Z-line

– Inferior esophageal sphincter• Just superior to Z-line, diaphragmatic musculature

forming the esophageal hiatus functions as this physiologic sphincter

– Food and liquid may be stopped momentarily here– Prevents reflux of gastric contents into esophagus

111

Phrenicoesophageal ligament connects esophagus flexibly to diaphragm; limits upward movement of esophagus while permitting some movement during respiration and swallowing

112

• Esophagus– Arterial supply

• Left gastric artery (branch from celiac trunk)• Left inferior phrenic artery

– Venous drainage• Primarily to portal venous system through left gastric vein• Proximal thoracic part drains into esophageal veins that enter

azygous vein– Lymphatic drainage

• Left gastric lymph nodes which dump into celiac lymph nodes– Innervation

• Vagal trunks (anterior and posterior gastric nerves) (from CN10)• Thoracic sympathetic trunks

– Greater (abdominopelvic) splanchnic nerves & periarterial plexus around left gastric artery and left inferior phrenic artery

113

114

• Clinical Note:– Esophageal varices

• Form in relation to portal hypertension– Increased blood pressure in portal venous system– Blood is unable to pass though liver via portal vein, causing reversal

of flow in esophageal tributary– Large volume of blood causes submucosal veins to enlarge and form

varices• Distended collateral channels

– If rupture will cause severe bleeding that is life-threatening and difficult to control

– Often seen in people with cirrhosis or other liver disease

115

• Clinical Note:– Pyrosis (heartburn)

• Most common type of esophageal discomfort or substernal pain

• Burning sensation in abdominal part of esophagus is usually due to regurgitation of food or gastric fluid into lower esophagus

• Associated with hiatal hernia

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• Stomach– Food blender & reservoir– Primary function is enzymatic digestion

• Gastric juice converts food into semi-liquid mixture known as chyme which will pass into duodenum

– Shape of stomach is dynamic & is variable– 4 parts and 2 curvatures

• Cardia– Surrounds cardial surface, opening of the esophagus into the stomach

• Fundus– Dilated superior part of the stomach that is related to left dome of diaphragm– May be dilated by gas, fluid, food

• Body– Major part of the stomach

• Pyloric part– Funnel-shaped region & consist of

» Pyloric antrum that leads into» Pyloric canal which is the narrow part» Pylorus is distal sphincteric region that has circular layer of smooth muscle

that controls discharge of stomach contents into duodenum• Lesser curvature

– Short concave border of stomach» Angular notch is sharp indentation that marks the junction of the body and

pyloric part of the stomach• Greater curvature

– Forms longer convex border of the stomach

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• Interior of the stomach– Gastric folds (gastric rugae)

• Longitudinal folds of gastric mucosa seen when stomach is contracted

• Most marked toward pyloric part and along greater curvature

– Gastric canal• Saliva and small quantities of food/liquids pass down

this furrow to pyloric canal when stomach is mostly empty

119

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• Clinical Note:– Hiatal hernia

• Protrusion of part of the stomach into the mediastinum through the esophageal hiatus of the diaphragm

• Two types:– Paraesophageal hiatal hernia

» Cardia remains in its normal position, but there is a pouch of peritoneum with part of the fundus that extends through esophageal hiatus

» Does not normally produce regurgitation– Sliding hiatal hernia

» Abdominal part of esophagus, cardia, and parts of fundus of stomach slide superiorly through esophageal hiatus into thorax

» Regurgitation is common

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• Vasculature and Nerves of the Stomach– Arterial supply

• Celiac trunk and its branches• Left & right gastric arteries

– Supplied by anatomoses formed along lesser curvature

• Right and left gastro-omental artery– Supply along greater curvature

• Short gastric & posterior gastric arteries– Branches of splenic artery– Supply fundus & upper body of the stomach

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• Vasculature and Nerves of the Stomach– Venous drainage

• Gastric veins– Parallel the arteries in position and course

• Left and right gastric veins– Drain directly into the portal vein

• Short gastric veins and left gastro-omental veins– Drain into splenic vein which joins the superior mesenteric

vein (SMV) to form the portal vein• Right gastro-omental vein

– Empties into the SMV

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• Gastric lymphatic vessels– Accompany the arteries along greater and lesser curvatures– Drain lymph into anterior & posterior toward curvatures

• Gastric and gastro-omental lymph nodes– Efferent vessels from these nodes accompany the large arteries to the celiac

lymph nodes

• Autonomic innervation– Parasympathetic

• From anterior vagal trunk– From left vagus nerve

• From posterior vagal trunk– From right vagus nerve

– Sympathetic• From T6-T9 segments of the spinal cord

– Pass to celiac plexus via greater splanchnic nerves

127

Lymphatic system also transports fat

128

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• Clinical Note:– Pylorospasm

• Spasmodic contraction of pylorus in infants (also rarely seen in adults)

– Usually between 2-12 weeks• Characterized by failure of smooth muscle

encircling pyloric canal to relax normally– Food does not pass easily from stomach

into duodenum– Stomach becomes overly full, and usually

results in vomiting (usually only when overeat)

– (congenital hypertrophic) Pyloric stenosis• Thickening of smooth muscle in pylorus

– Affects 1:150 male infants and 1:750 female infants

• Pylorus is hard and severe stenosis of pyloric canal is present

– Resist gastric emptying & the proximal part of the stomach becomes secondarily dilated due to pyloric obstruction projectile vomiting

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• Clinical Note:– Carcinoma of the stomach

• Extensive lymphatic drainage of the stomach & impossibility of removing all the lymph nodes creates a serious potential problem

– Can remove spleen, body and tail of pancreas, portion of greater omentum

– Gastrectomy• Total gastrectomy is uncommon• Partial gastrectomy

– May be performed to remove a region of the stomach involved by a carcinoma

– Arteries have a lot of anastomoses so have good collateral circulation. This allows one or more arteries to be ligated without serious problems

131

• Clinical Note:– Gastric Bypass

• Reduction in size of the stomach

• Many different techniques but majority of those performed in US is the Roux-en-Y bypass

Common for these people to be anemic b/c intrinsic factor is made in the stomach & we no longer have the stomach

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• Clinical Note:– Gastric ulcers

• Open lesion of the mucosa of the stomach• Peptic ulcer are lesions of the pyloric canal or duodenum• Most (9 of 10) are associated with bacteria Helicobacter pylori (H.

pylori)• Anxiety can cause stomach acid levels to be as high as 15X normal

between meals• Thought is acid content overwhelms bicarbonate & reduces the

effectiveness of the protective mucous lining leaving the lining open to pepsin (digest proteins)

• If erodes into gastric arteries = life-threatening bleeding• Treatment options:

– Antibiotics & anti-acids– Vagotomy = parietal cells are controlled by vagus nerve so remove

the innervation then decrease acid production

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Vagotomy = three locations: Above picture is truncal vagotomy. This is rare due to innervation of other abdominal structures is also sacrificed

Selective gastric vagotomy is seen in upper picture to right. Stomach is denervated, but vagal branches to pylorus, liver, and biliary ducts, intestines, and celiac plexus are preserved.

Selective proximal vagotomy is seen to the right. Attempts to denervate only the area where parietal cells are located

134

• Clinical Note:– Visceral referred pain

• Organ pain can vary from dull to severe, but is poorly localized.• Radiates to dermatome level which receives visceral afferent

fibers from the organ concerned– Example: gastric ulcer is referred to epigastric region as stomach is

supplied by pain afferent fibers from T7 and T8 spinal sensory ganglia through greater splanchnic nerve

– Parietal peritoneum pain• Well localized and usually severe• Has somatic sensory fibers through thoracic nerves• When pressure applied over area the parietal peritoneum is

stretched and when suddenly removed, there can be severe localized pain = rebound tenderness

135

This is good, but not definitive

If you are pushing on the diaphragm you will send pain up the phrenic nerve to C3, 4, & 5 & then you will experience pain in those dermatomes (why people w/ mono who have an enlarged spleen that is pushing on the diaphragm might be complaining of shoulder pain)

Surface anatomy of the stomach

136Pg 149

Going Back to Clarify

137

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• Small Intestine– Consist of duodenum, jejunum, and ileum– Extends from pylorus of the stomach to ileocecal junction– Duodenum

• First and shortest (25cm) part of small intestine• Widest and most fixed part• Begins at pylorus on right and ends at duodenojejunal junction on

left side• Four parts of the duodenum (see table 2.6)

– Superior (1st) part:» Short (5cm), mostly horizontal at L1 region

– Descending (2nd) part:» Longer (7-10cm), runs inferiorly along sides of L2 and L3

vertebrae curving around head of pancreas» Bile duct and pancreatic duct enter here

139

• Small Intestine– Duodenum

• Four parts of the duodenum (continued)– Horizontal (3rd) part:

» 6-8cm, crosses anterior to IVC and aorta to posterior to SMA at level of L3

– Ascending (4th) part:» Short (5cm), begins at left of L3 and rises superiorly to

border of L2, 2-3cm left of midline» Joins the jejunum at duodenojejunal junction where

there is an acute angle known as the duodenojejunal flexure that is supported by suspensory muscle of the duodenum (ligament of treitz)

140

• Small Intestine– Duodenum

• Suspensory muscle of the duodenum– Composed of slips of skeletal muscle from diaphragm and

fibromuscular band of smooth from 3rd and 4th parts of the duodenum

– Contraction of this muscle widens the angle of the duodenojejunal flexure which helps movement of intestinal contents

• Ampulla (duodenal cap)– First 2cm of superior part of duodenum– Has mesentery and is mobile– Remaining 3cm of superior part and other three parts of duodenum

have no mesentery and are immobile because they are retroperitoneal

141

A&B = superior part (1st)

C = descending part (2nd)

D = Horizontal or inferior part (3rd part)

E = Ascending part (4th)

142

• Small Intestine– Duodenum

• Arterial supply– Duodenal arteries arise from two different sources with

transition occurring at descending (2nd) part» Proximally, abdominal part of alimentary tract supplied

by celiac trunk and the 1st and 2nd parts of duodenum are supplied via gastroduodenal artery and its branch the superior pancreaticoduodenal artery

» Distally, major part of the alimentary canal is supplied by the superior mesenteric artery (SMA) and the 3rd and 4th parts of the duodenum are supplied by its branch the inferior pancreaticoduodenal artery

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• Small Intestine– Duodenum

• Duodenal veins– Follow the arteries and drain into portal vein

• Lymphatic vessels– Follow the arteries (retrograde direction)– Anterior lymphatic vessels drain into pancreaticoduodenal

lymph nodes and into pyloric lymph nodes– Posterior lymphatic vessels pass posterior to head of pancreas

and drain into the superior mesenteric lymph nodes• Innervation

– Parasympathetic innervation from vagus– Sympathetic innervation from greater and lesser splanchnic

nerves by way of celiac and superior mesenteric plexuses

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• Jejunum and Ileum– Begins at duodenojejunal junction and ileum ends

at ileocecal junction– Together are about 6-7m long in cadaver but

much shorter in living tissue– No clear separation between the two, they do

have distinctive characteristics (see table 2.7)– Mesentery

• Fan-shaped fold of peritoneum attaches the jejunum and ileum to posterior abdominal wall

147

• Jejunum and Ileum– Arterial supply

• SMA– Runs between layers of mesentery and sends many branches to

jejunum and ileum» These unite to form loops/arches known as arterial arcades that

give rise to vasa recta– Venous drainage

• SMV– Lies in root of mesentery (right of SMA)– Ends at neck of pancreas and unites with splenic vein to form portal

vein– Lymphatic vessels

• Lacteals– Within intestinal villi that absorb fat and drain into lymphatic plexuses

in walls of jejunum and ileum– Above drain into lymphatic vessels between layers of mesentery and

then through three groups of lymph nodes» Juxta-intestinal lymph nodes» Mesenteric lymph nodes» Superior central nodes» The above three sets of nodes drain into superior mesenteric

lymph nodes

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• Jejunum and Ileum– Autonomic innervation (perivascular nerve plexus)

• Sympathetic innervation– Reduces motility, and reduces secretion– Acts as a vasoconstrictor and stops digestion– Originate in T8-T10 segments of the spinal cord and reach superior

mesenteric nerve plexus through the sympathetic trunks and thoracic abdominopelvic and splanchnic nerves

» Presynaptic fibers synapse on cell bodies of postsynaptic neurons in the celiac and superior mesenteric (prevertebral) ganglia

• Parasympathetic innervation– Increases motility and increases secretion– Restores digestive activity– From posterior vagal trunk

» Presynaptic fibers synapse with postsynaptic neurons in the myenteric and submucous plexuses in intestinal wall

– Intestine is insensitive to most pain such as cutting, burning; but is sensitive to sudden distention and transient ischemia

• Colic = spasmodic abdominal pains

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Presynaptic sympathetic nerve fibers originate in T8 or T9 through T10 – T11 segments of the spinal cord and reach the celiac plexus through the sympathetic trunks and greater and lesser splanchnic nerves. After synapsing in the celiac and superior mesenteric ganglia, postsynaptic nerve fibers accompany the arteries to the intestine. Afferent fibers are concerned with reflexes and pain. Presynaptic parasympathetic fibers (CN X) originate in the medulla and pas to the intestine via the posterior vagal trunk. They synapse with intrinsic postsynaptic neurons located in the intestinal wall.

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• Clinical Note:– Malrotation of the midgut (BOARD QUESTION!)

• During development (in utero) the gut is herniated into the umbilical cord and is attached to the yolk sac

• Returns to abdominal region as more room becomes available, as this occurs it rotates about 270 degrees around the axis of the SMA

• Mesenteries also undergo modification• BOTTOM LINE = results in congenital anomalies such as

volvulus (twisting) of the intestine

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• Clinical Note:– Ischemia of the intestine

• Occlusion of the vasa recta by emboli• Severe = necrosis of a segment

– Ileus (obstruction of the intestine) of the paralytic type occurs.» Ileus has severe colicky pain and abdominal distension,

vomiting– Ileal diverticulum (Meckel’s diverticulum)

• Congenital anomaly (1-2% population)• Remnant of embryonic yolk stalk

– Always at site of attachment of the yolk stalk of ileum• May include areas of acid-producing gastric tissue, pancreatic tissue,

or jejunal or colonic mucosa– May become inflamed and produce pain mimicking appendicitis– If gastric tissue may get peptic ulcer at location

• Remember “2’s”– 2 ft. from cecum, 2 in. in length, 2% of population, 2%

symptomatic, males 2x more common, 2 types of ectopic tissue, most common age of diagnosis = 2

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Meckel’s diverticulum

155

• Large Intestine– Consist of cecum, colon (ascending, transverse,

descending, and sigmoid), rectum, and anal canal– Special features:

• Teniae coli– Three thickened bands of longitudinal muscle fibers

• Haustra– Pouches of the colon between teniae

• Omental appendices– Small, fatty projections of colon

• Caliber– Internal diameter is much bigger then small intestine

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• Large Intestine– Cecum

• First part of large intestine and is continuous with ascending colon• Blind intestinal pouch in right lower quadrant• Almost entirely enveloped by peritoneum however it has no mesentery• Ileum enters cecum at oblique angle and invaginates into it

– Forms folds superior and inferior to ileal orifice which form the ileocecal valve

– (Vermiform) appendix• Blind intestinal diverticulum that extends from posteromedial aspect of

cecum inferior to ileocecal junction• Varies in length and has a variable position, but almost always retrocecal

(behind cecum)• Has its own triangular mesentery = mesoappendix

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Cadaverliving

159

• Clinical Note:– Appendicitis

• Inflammation of the appendix• Common cause of acute abdomen• Causes:

– Young people = hyperplasia of lymphatic follicles that occlude the lumen

– Older people = obstruction from fecalith (coprolith)» Secretions cannot escape and the appendix swells, stretching the

visceral peritoneum• Pain

– Starts as vague in periumbilical region» Afferent pain fibers enter spinal cord at T10 level

– Progresses to severe pain in RLQ: due to irritation on parietal peritoneum lining posterior abdominal wall

• Thrombosis in appendicular artery– Acute infection may result in clotting which leads to ischemia,

gangrene and perforation of an acutely inflamed appendix• Rupture of the appendix

– Results in infection of the peritoneum, increased abdominal pain, N/V, and abdominal rigidity

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• Colon:– Four parts:

• Ascending, transverse, descending, and sigmoid• Ascending colon

– Passes superiorly on right side from cecum to right lobe of the liver

» Right colic flexure (hepatic flexure) = where it turns to the left

– Retroperitoneal and is covered by peritoneum anteriorly and on sides

» 25% of people have short mesentery– Separated from anterolateral wall by greater omentum– Right paracolic gutter = vertical groove lined with parietal

peritoneum on lateral aspect

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• Colon– Ascending

• Arterial supply– Branches of the SMA

» Ileocolic and right colic arteries• Venous drainage

– Tributaries of the SMV» Ileocolic and right colic veins

• Lymphatic vessels– Epicolic and paracolic lymph nodes → ileocolic and right

colic nodes → superior mesenteric nodes• Nerves

– Superior mesenteric plexus

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• Colon– Transverse

• Largest and most mobile part of large intestine• Crosses abdomen from right colic flexure to left colic

flexure (splenic flexure)– More superior, more acute, and less mobile then right flexure– Anterior to inferior part of left kidney– Attaches to diaphragm via phrenicocolic ligament

• Transverse mesolon– Mesentery of transverse colon

» Loops down to ~level of iliac crest and adheres to posterior wall of omental bursa

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• Colon– Transverse

• Arterial supply– Middle colic artery = a branch of SMA– Anastomosis from right and left colic arteries

• Venous drainage– SMV

• Lymphatic drainage– Middle colic lymph nodes → superior mesenteric lymph

nodes• Nerves

– Superior mesenteric plexus

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• Colon– Descending

• Passes retroperitoneally from left colic flexure into left iliac fossa where it joins sigmoid colon

• Peritoneum covers anterior and lateral surfaces and binds it to posterior abdominal wall

– Short mesentery in 33% of population

• Passes anterior to lateral border of left kidney• Paracolic gutter on lateral aspect

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• Colon– Sigmoid colon

• Characterized by S-shaped loop• Extends from iliac fossa to third sacral segment

– Here it joins rectum

• Rectosigmoid junction– Located by end of teniae coli

• Sigmoid mesocolon– Long mesentery that allows for movement (lots)

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• Colon– Descending and sigmoid colon

• Prior to here all blood basically supplied by SMA• Here down is supplied by inferior mesenteric artery (IMA)• Arterial supply

– Left colic and sigmoid arteries = branches of IMA» Divide into ascending and descending branches

– ALL (at least most) of arteries supplying blood to colon• Ileocolic, right, middle, and left colic; and sigmoid• Anastomose with each other as they approach colon to form a

continuous anastomotic channel = marginal artery– Provides very important collateral circulation

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• Colon– Descending and sigmoid colon

• Venous drainage– Inferior mesenteric vein (IMV) which flows into the splenic

vein and then into portal vein in way to liver• Lymphatic vessels

– Epicolic and paracolic nodes → intermediate colic nodes → inferior mesenteric nodes

– Lymph from left colic flexure may pass to superior mesenteric lymph nodes

• Autonomic Innervation– Sympathetic

» Lumbar part of sympathetic trunk via lumbar (abdominopelvic) splanchnic nerves, superior mesenteric plexus, periarterial plexuses on IMA

– Parasympathetic» Pelvic splanchnic nerves via inferior hypogastric

(pelvic) plexus

168

169

Good picture to study!!

170

Dang! Look at all of those lymph nodes!

171

Parasympathetic has ABSOLUTELY NO CONTROL over blood flow (vasodilation is merely a function of on & of sympathetic innervation)

• Clinical Note:– Colitis (ulcerative and Crohn

disease)• Chronic inflammation & ulceration of

the colon and rectum– Colectomy

• Terminal ileum, colon, rectum, anal canal are removed

– Ileostomy• Opening between ileum and skin

– Colostomy• Opening into colon (from skin)

– Sigmoidostomy• Opening between sigmoid colon and

skin (artificial anus)

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173

• Clinical Note:– Colonoscopy

• Observation of the interior of the colon

• Uses endoscope (colonoscope)

– Flexible tube that inserts through anus and rectum

– Instruments can be passed through it for minor procedures such as biopsies

– Most tumors of large intestine:

» Occur in rectum with 12% near rectosigmoid junction

– Sigmoidoscopy• Observation of interior of

sigmoid colon

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• Clinical Note:– Diverticulosis

• Multiple false diverticula that develop in intestine

– External evaginations or out-pockets of mucosa of the colon

• Common (60%) in sigmoid colon

• Colonic diverticula are not true diverticula

– Protrusions of mucous membrane only

– Diverticulitis• Diverticula are subject to

infection and rupture• Distort and erode nutritional

arteries and lead to hemorrhage

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• Spleen– Mobile ovoid lymphatic organ in LUQ– Intraperitoneal

• Surrounded by peritoneum except at hilum– Hilum = where splenic artery and vein enter/leave

– Location• Posterior = 9th – 11th ribs (separated by diaphragm and

costodiaphragmatic recess)– Does not normally descend inferior to costal region

– Size• About size of clinched fist (12cm long X 7cm wide)

– Shape• Diaphragmatic surface of the spleen

– Curved to fit concavity of diaphragm» Anterior and superior borders are sharp» Posterior and inferior borders are rounded

– Attachments• Gastrosplenic ligament = posterior wall of stomach• Splenorenal ligament = left kidney

– Both of these ligaments contain splenic vessels and are attached to hilum

• Hilum of spleen often in contact with tail of the pancreas

176

177

• Spleen– Splenic artery

• Largest branch of celiac trunk• Posterior to omental bursa, anterior to left kidney along superior

border of pancreas• Divides into 5+ branches that enter hilum of spleen dividing into 2-

3 vascular segments– Splenic vein

• Formed by several tributaries that emerge from hilum• Joined by IMV and runs posterior to pancreas• Unites with SMV to form portal vein

– Lymphatic vessels• Leave nodes in hilum and pass to pancreaticosplenic nodes

– Innervation• Celiac plexus

Most common traumatic damage = damage to the spleenMost common organ to be damaged d/t penetration = small intestine

178

• Clinical Note:– Rupture of spleen

• Most frequently injured organ in the abdomen• Blunt trauma can cause sudden marked increase in intra-abdominal

pressure which often causes thin capsule and overlying peritoneum to burst

– If rupture there is profuse bleeding and shock

– Splenectomy• Often performed to prevent person from bleeding to death• Does not produce serious effects

– Functions are assumed by other organs (liver, bone marrow)– Does have increase susceptibility to certain bacterial infections

– Splenomegaly• Not usually palpable in adults• If palpable at lower costal margin at end of inspiration then it is enlarged

about three times “normal” size

179

Surface anatomy spleen and pancreas

180

• Pancreas– Elongated retroperitoneal accessory digestive gland– Location

• Lies transversely across posterior abdomen wall, posterior to stomach between duodenum on right and spleen on left

– Secretions• Exocrine

– Pancreatic juice from acinar cells that enter duodenum• Endocrine

– Glucagon and insulin from pancreatic islets that enter blood– Divisions

• Four parts– Head of pancreas

» Embraced by C-shape curve of duodenum– Neck of the pancreas

» Short and overlies superior mesenteric vessels– Body of pancreas

» Lies to left of SMA and SMV– Tail of pancreas

» Closely related to hilum of spleen and left colic flexure

181

• Pancreas– Pancreatic duct

• Begins in tail and runs through parenchyma to head• Merges with the bile duct (common bile duct)

– (Common) bile duct• Crosses posterosuperior surface of head of pancreas or is

embedded in head of pancreas– Hepatopancreatic ampulla

• Pancreatic and bile ducts unite here• Opens into descending part of duodenum at the major duodenal

papilla via the hepatopancreatic sphincter (sphincter of Oddi)– All sphincters (sphincter of pancreatic duct, sphincter of bile duct,

and above) are smooth-muscle sphincters that control flow of juices into duodenum

– Accessory pancreatic duct• Opens into duodenum at minor duodenal papilla

– Usually communicates with main pancreatic duct

182Fig 2.23

183

184

Arterial supply =Pancreatic arteries

Derive from branches of the splenic artery

Anterior and posterior superior pancreaticoduodenal arteries

Branches of gastroduodenal artery

Anterior and posterior inferior pancreaticoduodenal arteries

Branches of the SMA

185

Venous drainage =

Pancreatic veins are tributaries of the splenic and superior mesenteric parts of portal vein

186

Pancreatic lymphatic vessels follow blood vessels. Most are pancreaticosplenic nodes along splenic artery. Some end in pyloric nodes. These drain to superior mesenteric nodes or to celiac nodes via hepatic nodes

187

Nerves of pancreas = derived from vagus and abdominopelvic splanchnic nerves passing through diaphragm

Parasympathetic and sympathetic fibers are from celiac and superior mesenteric plexuses

188

• Clinical Note:– Blockage of the hepatopancreatic ampulla

• Gallstone may lodge in distal end of ampulla– Both biliary and pancreatic duct systems are blocked and neither bile

nor pancreatic juice can enter duodenum– Bile may back up and enter pancreatic duct

– Pancreatitis• Inflammation of the pancreas

– May be due to bile entering pancreatic duct

– Spasms of hepatopancreatic sphincter• Reflux of bile• Normally sphincter prevents this, but if obstructed or cannot

withstand increased pressure from backed up bile

189

• Clinical Note:– Rupture of pancreas

• Centrally located in body and is usually well protected from injury• Forceful compression or penetrating injury can result in rupture of the

pancreas, or tearing of the duct system– Allow pancreatic juice to enter parenchyma of gland and invade adjacent

tissues» Digestion of pancreatic tissues and other adjacent structures by

pancreatic juice is very painful

– Pancreatic cancer• Accounts for most cases of extrahepatic obstruction of the biliary ducts• Obstruction results in retention of bile pigments, enlargement of

gallbladder and jaundice• Pancreas extensive drainage to inaccessible lymph nodes and the fact that

it metastasizes to liver early via portal vein makes surgical resection futile• Median survival time regardless of therapy is 2-3 months after diagnosis

190

• Liver– Largest internal organ and largest gland in the

body– Diaphragm separates liver from thorax– Every substance (except lipids) absorbed by the

alimentary tract is received first by the liver– Stores glycogen and secretes bile (in addition to

many metabolic activities)

191

• Liver– Surface

• Diaphragmatic surface– Smooth and dome shaped– Subphrenic spaces (recesses)

» Superior extensions of peritoneal cavity between superior liver and diaphragm

» Separated by falciform ligament– Covered with peritoneum except in

bare area of the liver (where in direct contact with diaphragm)

• Visceral surface– Covered with peritoneum except at bed

of gallbladder and porta hepatis– Porta hepatis

» Transverse fissure in middle visceral surface of liver

» Gives passage to portal vein, hepatic artery, hepatic nerve plexus, hepatic ducts, lymphatic vessels

192

• Liver– Lesser omentum

• Encloses portal triad (portal vein, hepatic artery, bile duct)

• Passes from liver to lesser curvature of stomach• Hepatoduodenal ligament

– Thickened free edge of lesser omentum between porta hepatis and duodenum

– Encloses structures that pass through porta hepatis

193

194

• Liver– Lobes and segments

• Anatomic– Based on external features and has 4 lobes: right, left, caudate,

quadrate» Visceral surface right and left sagittal fissure and porta hepatis

demarcate caudate lobe and quadrate lobe (both part of right lobe)

• Functionally (in terms of blood supply and glandular secretions)– Two independent livers (right and left) – portal lobes

» Separated by falciform ligament and left sagittal fissure» Each portal lobe has its own blood supply from the hepatic artery

and portal vein and its own biliary drainage» Portal lobes are further subdivided into eight segments

• Right sagittal fissure– Continuous groove formed by fossa for gallbladder anteriorly and

inferior vena cava posteriorly• Left sagittal fissure

– Continuous groove anteriorly by fissure for the round ligament (ligamentum teres)

» Round ligament of the liver is remains of umbilical vein– fissure of ligamentum venosum posteriorly

» Remnant of fetal ductus venosus (shunt blood from umbilical vein to IVC

195

Four anatomic lobes of the liver defined by external features. Left sagittal fissure demarcate right and left lobes. Right and left sagittal fissures and porta hepatis form an H on visceral surface demarcating the quadrate and caudate lobes

Structures forming the fissures of visceral surface. Round ligament of liver is the occluded remains of the fetal umbilical vein. Ligamentum venosum is remnant of the ductus venosum that shunted blood from umbilical vein to IVC

196

• Liver– Vasculature

• Blood from two primary sources– Portal vein (75% - 80%)

» Poorly oxygenated blood from abdominopelvic portion of GI tract

– Hepatic artery (20% - 25%)» From celiac trunk – carries well-oxygenated blood from aorta

• At porta hepatis the above two terminate and divide into right and left branches to supply the two portal lobes

– Within each lobe the two come together and form vascular segments– Between segments are right, intermediate (middle), and left hepatic

veins which drain parts of adjacent segments• Hepatic veins open into IVC just inferior to diaphragm

197

Each of the 8 lobes above has its own blood supply and biliary drainage. Each segment can be surgically resected. Do not memorize these segments. See fib 2.27 in your book

198

• Clinical note:– Rupture of the liver

• Easily injured due to its large fixed position. It is also very friable (easily crumbled)

• Large blood supply, can lead to large blood loss and pain in RUQ

• Treatment by just removing foreign material or segmentectomy

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• Liver– Lymphatics

• Major lymph-producing organ– ¼ - ½ of the lymph received by thoracic duct comes from the liver

• Superficial lymphatics are found on outer surface• Deep lymphatics are in connective tissue converging on portal

triad and hepatic veins• Anterior aspects of superficial lymphatics and deep lymphatic

vessels accompanying portal triad– Drain to hepatic lymph nodes along hepatic vessels and ducts in

lesser omentum → drain into celiac lymph nodes → chyle cistern at inferior end of thoracic duct

• Posterior aspects– Drain toward bare area of liver and drain into phrenic lymph nodes

or join deep lymphatics that accompany hepatic veins converging on IVC → drain into posterior mediastinal lymph nodes → join right lymphatic and thoracic ducts

200

201

Nerves of the liver: derive from hepatic nerve plexus which is the largest derivative of the celiac plexus. Sympathetic fibers from celiac plexus. Parasympathetic fibers from anterior and posterior vagal trunks

202

• Clinical Note:– Hepatomegaly (liver enlargement)

• Liver is soft and highly vascular and receives a large amount of blood immediately before it enters the heart

– Both IVC and hepatic veins lack valves– Any rise in central venous pressure is directly transmitted to liver

which makes it enlarge as it engorges with blood» Can stretch capsule which will produce pain around lower ribs» FYI: a temporary form of this is thought to be the cause of

“runners stitch” especially with increased diaphragm activity– Metastatic carcinoma

• Common site due to receiving blood from organs drained by portal system– Cirrhosis

• Primary site of detoxification of substances absorbed by digestive system– Vulnerable to cellular damage and scarring– Progressive destruction of hepatocytes and replaced by fat and fibrous

tissue» Fibrous tissue surrounds intrahepatic blood vessels and biliary

ducts impeding the circulation of blood causing portal hypertension

– Alcoholic cirrhosis is the most common cause of portal hypertension

203

• Biliary ducts and gallbladder– Bile produced continuously in liver and stored in gallbladder– Gallbladder

• Stores, concentrates it by absorbing water and salts• Fat enters duodenum

– GB sends concentrated bile through cystic and bile ducts to duodenum» Bile emulsifies the fat so it can be absorbed in distal intestine

– Bile formation• Hepatocytes secrete bile into bile canaliculi. • Canaliculi drain into small interlobular biliary ducts and then into large

collecting bile ducts of the intrahepatic portal triad– Merge to form right and left hepatic ducts

• Hepatic ducts drain the right and left portal lobes of liver• Common hepatic duct = right and left hepatic ducts unite to form this• Cystic duct = joins common hepatic duct on right to form bile duct

204

Small part of liver showing the components of the interlobar portal triad and the positioning of the sinusoids and bile canaliculi

Note: Bile duct is current name (formally known as common bile duct)

205

• Gallbladder– Pear-shaped organ located in gallbladder fossa on visceral surface of

the liver– Peritoneum surrounds fundus of GB and binds body and neck to the

liver– GB has three parts

• Fundus– Wide end, projects from inferior border of liver and tip of right 9th costal

cartilage in midclavicular line• Body

– Contacts visceral surface of liver, transverse colon and superior part of the duodenum

• Neck– Narrow, taped and directed toward porta hepatis– Makes an S-shaped bend and joins cystic duct

» Spiral valve (folds of mucosa) keep cystic duct open so bile can divert into GB

» when distal end of bile duct is closed or when bile passes to duodenum as the GB contracts the cystic duct connects the neck of the GB to the common hepatic duct

206

• Gallbladder– Arterial supply

• Cystic artery supplies GB and cystic duct• Arises from right hepatic artery

– Venous drainage• Cystic veins drain biliary ducts and neck of GB• Pass to liver directly or drain through portal vein to liver• Veins from fundus and body pass directly into liver and drain into

hepatic sinusoids– Lymphatic drainage

• Hepatic lymph nodes often via cystic lymph nodes → celiac lymph nodes

– Innervation• Celiac nerve plexus

– Sympathetic and visceral pain)• Vagus nerve• Right phrenic nerve

207

• Clinical Note:– Gallstone

• Composed mainly of cholesterol crystals• Much more common in females and incidences increase with age• Common site of blockage is at distal end of the hepatopancreatic

ampulla (narrowest part of biliary passages)– May also lodge in hepatic and cystic ducts– Causes intense spasmodic pain

– Cholecystitis• Stone blocks the cystic duct get inflammation of GB• May get pain in posterior thoracic wall or right shoulder due to

irritation of diaphragm• Jaundice occurs if bile cannot leave the GB, it enters blood

208

• Portal venous system – Portal vein main channel – Collects poorly oxygenated, but nutrient rich blood from abdominal

part of alimentary tract– Branches distributed in a segmental pattern and end in expanded

capillaries = venous sinusoids of liver• Portal vein and portal-systemic anastomoses

– Where portal venous system communicates with the systemic venous system

• Esophageal veins draining into either azygos (systemic) or left gastric vein (portal)

– When dilated = esophageal varices• Rectal veins draining into IVC (systemic) and superior rectal vein

continuing as inferior mesenteric vein (portal system)– When dilated = hemorrhoids

• Paraumbilical veins (portal system) anastomosing with superiorficial epigastric veins (systemic)

– When dilated = caput medusae

209

Anastomoses provide a collateral circulation in cases of obstruction in the liver or portal vein

A = esophageal vein draining into azygos or left gastric when dilated these are esophageal varices

B = Inferior and middle rectal veins draining into IVC and superior rectal vein, continuing as inferior mesenteric vein when dilated known as hemorrhoids

C = paraumbilical veins anastomosing with small epigastric veins of anterior abdominal wall and may produce caput medusae

210

• Clinical Note:– Portosystemic shunts

• Method for reducing portal HTN– Divert blood from portal system to systemic venous system by

creating a communication between portal vein and IVC

211

• Kidneys– Retroperitoneal on posterior abdominal wall

• Each side of vertebral column– Remove excess water, salts and protein metabolism from

blood• Ureters

– Tubes from kidneys to bladder• Urinary bladder

– Storage container for urine• Suprarenal (adrenals)

– Part of endocrine system and are completely separate in function to kidneys

212

213

• Renal fascia and fat– Perinephric fat (perirenal fat capsule)

• Surrounds kidneys and suprarenal glands

– Renal fascia• Membranous layer that surrounds kidneys, suprarenals and

perinephric fat

– Periureteric fascia• Continuation of renal fascia along ureters

– Paranephric fat (pararenal fat body)• External to renal fascia (extraperitoneal fat of the lumbar region)

and is seen posterior to kidney

– All above allows for movement of kidney and is about 3cm with change of position

214

215

• Kidneys– Posterior abdominal wall at level of T12 – L3 vertebrae

• Right kidney is slightly lower then left (liver)– Renal hilum

• Entrance to space within the kidney– Renal vein is anterior to renal artery which is anterior to renal pelvis

– Renal sinus• Occupied mostly by fat, is where renal pelvis, calices, vessels, and

nerves are embedded– Location:

• Superiorly = diaphragm• Inferior = quadratus lumborum muscle• Viscera = sits behind all other viscera

216

217

• Kidneys – Ureters– Ureters

• Muscular ducts with narrow lumen that carry urine from kidneys to urinary bladder

– Ureter-Kidney internal anatomy• Renal pelvis

– Superior, expanded end of ureter• Major calices (calyces)

– 2-3 of these come together to form renal pelvis• Minor calices (calyces)

– 2-3 of these come together to form major calices• Renal papilla (apex of renal pyramid)

– Indents apex of each minor calices– Ureter course

• Pass inferomedially along transverse processes of lumbar vertebrae and cross external iliac artery just beyond bifurcation of common iliac artery (where the aorta splits)

• Normally constricted in three places (and sites of kidney stone obstruction):

– Junction of ureters and renal pelvis– Ureters cross brim of pelvis inlet– Passage through wall of urine bladder

218

219

• Suprarenal (adrenal) glands – think of this as your 911 response area

– Located between superomedial aspects of kidney and diaphragmatic crura

– Surrounded by connective tissue• Contains perinephric fat and are enclosed by renal fascia

– Attached to diaphragm• Separated from kidneys by fibrous tissue

– Shape• Right adrenal is pyramidal-shaped and makes contact with IVC and

liver• Left adrenal is crescent-shaped and makes contact with spleen,

stomach, and pancreas– Parts

• Cortex = corticosteroids, and androgens• Medulla = epinephrine (adrenalin) and norepinephrine (noradrenalin)

220

• Vasculature of kidneys– Renal arteries

• From aorta at level of IV disc between L1 and L2

• Each divides close to hilum into 5 segmental arteries

– Distributed to segments of the kidneys

– End arteries – if you kick clots into your kidneys you will kill parts of it

– Renal veins• Formed by several veins that drain

kidney and unite• Lie anterior to renal arteries• Drain into IVC

• Vasculature of ureters– Arteries to the ureters

• Three sources– Renal artery, testicular artery (or

ovarian artery), & abdominal aorta– Veins of the ureters

• Drain into the renal and testicular (or ovarian) veins

221

222

• Vasculature of the suprarenals– Endocrine function makes it necessary for abundant blood

supply– Suprarenal arteries arise from three sources

• Superior suprarenal arteries (6-8)– From inferior phrenic artery

• Middle suprarenal arteries (1 or more)– From abdominal aorta near SMA

• Inferior suprarenal arteries (1 or more)– From renal artery

– Venous drainage• Into large suprarenal vein

– Right suprarenal drains into IVC– Left suprarenal drains into left renal vein

224

• Renal lymphatic vessels– Follow renal veins and drain into lumbar lymph nodes

• Ureter– Superior part drain into lumbar nodes– Middle part drain into common iliac nodes– Inferior part drain into common, external, or internal iliac

nodes

• Suprarenal glands– Lymphatic vessels arise from deep plexus and pass into

lumbar lymph nodes

225

226

Nerves to kidneys and ureters arise from renal nerve plexus and consist of sympathetic, parasympathetic and visceral afferent fibers. Suprarenal glands have rich nerve supply celiac plexus and abdominopelvic splanchnic nerves

Summary of Innervation of Abdominal Viscera

• Autonomic nerves of abdomen– Splanchnic nerves and one cranial nerve

• Deliver presynaptic sympathetic and parasympathetic fibers to abdominal aortic plexus and associated sympathetic ganglion

• Periarterial extensions of these plexuses deliver postsynaptic sympathetic fibers (and continuation of parasympathetic fibers to abdominal viscera)

227

228

• Sympathetic part of ANS in abdomen– Abdominopelvic splanchnic nerves

• Convey presynpatic sympathetic fibers to abdominopelvic cavity– Originate from lateral horn of gray matter in cord (T7 – L2/L3 region)– Fibers pass through anterior root → anterior rami → white

communicating branch of thoracic and upper lumbar segements → sympathetic trunks (no synapse) → abdominopelvic splanchnic nerves → prevertebral ganglia of abdominal cavity

• Abdominopelvic splanchnic nerves include lower thoracic and lumbar splanchnic nerves

– Lower thoracic splanchnic nerves» Main source of presynaptic sympathetic fibers serving

abdominal viscera» Greater splanchnic nerve (T5-T9), Lesser splanchnic nerve (T10-

T11) and least splanchnic nerve (T12) are specific thoracic splanchnic nerves that send fibers to celiac, superior mesenteric and prevertebral sympathetic ganglion

– Lumbar splanchnic nerves» From abdominal part of sympathetic trunk» Pass to intermesenteric, inferior mesenteric and superior

hypogastric plexuses

229

• Sympathetic part of ANS in abdomen– Cell bodies of postsynaptic sympathetic neurons = major

prevertebral ganglia that cluster around roots of major branches of abdominal aorta

• Celiac, aorticorenal, superior mesenteric and inferior mesenteric ganglia

• Synapse between presynaptic and postsynaptic fibers pass from prevertebral ganglia to abdominal viscera through periarterial plexuses associated with branches of abdominal aorta

– Involved with vasoconstriction and acts to inhibit peristalsis– Adrenal glands is exception = medulla are postsynaptic and is

supplied directly by presynaptic neurons

230

231See table 2.9!

232

• Visceral afferent fibers (pain)– Accompany sympathetic motor fibers– Pass retrograde to motor fibers along splanchnic nerves to

sympathetic trunk• Pass through white communicating branch → anterior rami →

posterior root → to spinal sensory ganglia and spinal cord

– At midpoint of sigmoid colon– Visceral pain fibers run with parasympathetic fibers to S2-

S4 sensory ganglia and spinal cord• Same spinal cord segments involved with sympathetic innervation

of those portions of GI tract

233

See table B2.2 in your text

234

• Parasympathetic part of ANS– Anterior and posterior vagal trunks

• Continuation of left and right vagus nerves that emerge from esophageal plexus and pass through esophageal hiatus

• Convey presynaptic parasympathetic and visceral afferent fibers to abdominal aortic plexuses and periarterial plexuses

– (unconscious sensations associated with reflexes)

– Pelvic splanchnic nerves• Distinct from other splanchnic nerves

– Nothing to do with sympathetic trunks– Derive from anterior rami of spinal nerves S2-S4– Convey presynaptic parasympathetic fibers to inferior hypogastric

(pelvic) plexus

– Presynaptic fibers terminate on isolated and widely scattered cell bodies of postsynaptic neurons lying on or within abdominal viscera

235

• Analogy:– House has electrical power coming to it for all the various activities

you need to do to live– The power is = to nerve signals– You have two different types of functions or needs of electrical power

in your house• 1) power at your outlets that are distributed in every room (level) of your

house that you plug your cords into– Sympathetic fibers

» Relatively short preganglionic (wires in walls) you plug in your long cords (post ganglionic) to specific functions that you need

• 2) power for things like your furnace…you do not directly plug anything in, but it is essential to the overall function of your house.

– Parasympathetic» Long preganglionic (wires go all the way to furnace, water heater etc)

there are no direct plugs for you to check on– All power goes to a central point or a fuse box that can be

switched/monitored as needed. Has both types of power, but still distinct pathways

• this is equal to your plexuses

236

• Nerve plexuses– Abdominal autonomic plexus

• The autonomic plexuses of the abdomen are a collection of parasympathetic and sympathetic nerve fibers that coalesce to innervate the viscera of the abdomen.

The major autonomic plexuses of the abdomen are the celiac, superior mesenteric, intermesenteric, inferior mesenteric, and superior hypogastric plexuses. The renal plexus lies along the renal vessels.

The named prevertebral or preaortic ganglia in the abdomen are the paired celiac, the superior mesenteric, paired aorticorenal, and the inferior mesenteric. These ganglia are all sympathetic, of course, since all parasympathetic fibers (below the head, that is) synapse in the wall of the target organ.

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• Diaphragm– Musculotendinous partition between thorax and abdominal cavities– Chief muscle of inspiration

• Descends during inspiration– Only central part moves due to fixed origins of muscle

– Right dome is slightly higher due to liver• During expiration the right dome reaches as high as 5th rib and left dome to 5th

intercostal space– Central tendon

• Trifoliate central aponeurosis– No bony attachments and divided into three leaves (cloverleaf)

• Superior aspect fused with inferior surface of fibrous pericardium– Three parts of muscular portion of diaphragm (continuous)

• Sternal part– Two muscular slips that attach to posterior aspect of xiphoid process. May not

always be present• Costal part

– Wide muscular slips that attach to internal surfaces of inferior six costal cartilages and adjoining ribs on each sides

– Forms domes of diaphragm• Lumbar part

– Two aponeurotic arches» Medial and lateral arcuate ligaments

– Three lumbar vertebrae– Forms muscular crura that ascend to central tendon

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• Diaphragm Apertures– Permit structures to pass between thorax and the abdomen– Three large apertures for IVC, esophagus, and aorta

• Caval opening– Primarily for IVC, but also has branches of right

phrenic nerve and some lymphatic vessels– This opening widens when diaphragm contracts

» Facilitates blood flow to the heart• Esophageal hiatus

– Primarily for esophagus, but also has anterior and posterior vagal trunks and a few lymphatic vessels

– Fibers cross inferior to hiatus and form a muscular sphincter for the esophagus that constricts when diaphragm contracts

• Aortic hiatus– Posterior to diaphragm, transmits aorta, azygos

vein, and thoracic duct– Aorta does not pierce diaphragm

» Blood flow is not affected by muscle’s movement during respiration

» Passes between crura of diaphragm posterior to median arcuate ligament at level of T12

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• Vasculature of the diaphragm– Arteries of the diaphragm

• Branch like pattern of superior and inferior surfaces• Superior surface

– Pericardiacophrenic and musculophrenic arteries» Branches of the internal thoracic artery

– Superior phrenic arteries» From thoracic aorta

• Inferior surface– Inferior phrenic arteries

» First branch of the abdominal aorta (may arise from celiac trunk)

– Venous drainage• Superior surface

– Pericardiacophrenic and musculophrenic veins» Empty into internal thoracic veins» Right side a superior phrenic vein that drains into IVC» Some drainage into azygos and hemiazygos veins

• Inferior surface– Right inferior phrenic vein usually opens into IVC– Left inferior phrenic vein (usually double) drains to IVC and

suprarenal vein

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Picture on left: arteries and veins of the superior surface of the diaphragm are derived from pericardiacophrenic and musculophrenic arteries and veins and from the superior phrenic arteries. Picture on right: inferior phrenic arteries and veins supply and drain blood from inferior surface of the diaphragm. Inferior phrenic arteries are usually first branches of abdominal aorta

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Lymphatic plexuses on thoracic and abdominal surfaces communicate freely. Anterior and posterior diaphragmatic lymph nodes are on thoracic surface and drain into parasternal, posterior mediastinal and phrenic lymph nodes. Abdominal surface drain into the anterior diaphragmatic, phrenic, and superior lumbar (caval/aortic) lymph nodes. Lymphatics are dense in inferior surface and are primary means for absorption of peritoneal fluid

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Entire motor supply to diaphragm is from right and left phrenic nerves.

Arise from anterior rami of C3-C5

Also supply sensory fibers to most of diaphragm

Peripheral parts of the diaphragm receive sensory nerve supply from intercostal nerves and subcostal nerves

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• Clinical Note:– Hiccups

• Involuntary, spasmodic contractions of the diaphragm that cause sudden inhalations.

• These inhalations are interrupted by spasmodic closure of the glottis which monitors inflow of air

• Result from irritation of nerve endings or medullary centers in brainstem that control muscles of respiration

• Have many causes: indigestion, diaphragm irritation, alcoholism, cerebral lesions, or anything that would irritate the phrenic nerve

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• Clinical Note:– Section of phrenic nerve

• Paralysis of muscular part of corresponding half if diaphragm• Paralysis of hemidiaphragm can be seen radiographically by

permanent elevation and paradoxical movement

Posterior Abdominal Wall• Fascia of the posterior abdominal wall

– Posterior abdominal wall covered with continuous layer of endoabdominal fascia

• Lies between parietal peritoneum and muscles– Fascia lining posterior abdominal wall is continuous with transversalis fascia

• Fascia is named by the structure it covers– Psoas fascia

» Covers psoas major and is thickened superiorly to form medial arcuate ligament

• Thoracolumbar fascia– Extensive fascial complex with anterior, middle and posterior layers

» Posterior and middle layers enclose vertical deep back muscles (erector spinae)

» Anterior layers covers quadratus lumborum and attaches to anterior surface of the transverse process of lumbar vertebrae

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• Muscles of posterior abdominal wall– Paired muscles

• Psoas major– Lateral to lumbar vertebrae– Greek for “muscle of the loin”

» Butchers refer to the psoas of animals as the “tenderloin”

• Iliacus– Large triangle muscle along lateral side of inferior part of psoas– Together with psoas forms iliopsoas: chief flexor of the thigh

• Quadratus lumborum– Forms thick muscular sheet in posterior abdominal wall– Adjacent to lumbar transverse processes

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See table 2.14, pg 334 for attachments, innervation, and actions

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• Clinical Note:– Psoas sign:

• Iliopsoas is in close contact with kidneys, ureters, cecum, appendix, sigmoid colon, pancreas, lumbar lymph nodes, nerves of posterior abdominal wall

• When any of above are injured/diseased movement of iliopsoas will cause pain

• Clinical test– Person lies on unaffected side and extend thigh on affected

side against resistance of examiners hand» Pain is a positive psoas sign

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• Nerves of the posterior abdominal wall– Subcostal nerves (anterior rami of T12)

• Supply external oblique and skin of anterolateral abdominal wall– Lumbar spinal nerves

• Posterior rami supply deep muscles of the back• Anterior rami supply skin and muscles of interiormost trunk and

lower limb– Lumbar plexus of nerves

• Anterior rami of L1 – L4 nerves– All rami receive gray communicating branches from sympathetic

trunk• Branches of lumbar plexus:

– Obturator nerve (L2-L4)– Femoral nerve (L2-L4)– Lumbosacral trunk (L4, L5)– Ilioinguinal and iliohypogastric nerves (L1)– Genitofemoral nerve (L1, L2)– Lateral cutaneous nerve of the thigh (L2, L3)

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• Vasculature of the posterior abdominal wall– Abdominal aorta

• About 13 cm in length begins at aortic hiatus in diaphragm at level of T12 and ends at level of L4 by dividing into two common iliac arteries

– Lumbar arteries» Supply lumbar vertebrae

– Common iliac arteries• Terminal branches of abdominal aorta• Divide into internal and external iliac arteries

– Internal iliac artery• Enters pelvis and supplies pelvic viscera

– External iliac artery• Follows iliopsoas muscle and leaves abdominal cavity• Gives off inferior epigastric and deep iliac circumflex arteries

– Supply anterolateral abdominal wall

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• Vasculature of the posterior abdominal wall– Tributaries of the inferior vena cava

• Except left testicular or ovarian vein– Left side drains into left renal vein

– IVC• Largest vein in the body• Has no valves• Returns poorly oxygenated blood from lower limbs, most of back,

abdominal walls, abdominopelvic viscera– Passes through the portal venous system first

• Begins anterior to L5 vertebrae by union of common iliac veins• Ascends on right side of bodies of L3-L5 vertebrae• Leaves abdomen by passing through caval opening in diaphragm

to enter the thorax• Tributaries of the IVC correspond to branches of the aorta

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• Clinical Note:– Abdominal aortic aneurysm

• A localized enlargement of the aorta (where blood get in b/w the layers of the lumen)

• Deep palpation can detect an aneurysm which is weakness of the arterial wall

• Acute rupture is associated with severe pain in abdomen and back and has a mortality rate of about 90% due to heavy blood loss

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• Lymphatics of posterior abdominal wall– Lymphatic vessels and nodes lie along aorta, IVC and iliac vessels– Common iliac nodes

• receive lymph from external and internal iliac nodes• Pass lymph to lumbar lymph nodes

– Lumbar lymph nodes• Receive lymph directly from posterior abdominal wall, kidneys, ureters,

testes, ovaries, uterus, uterine tube• Also receive lymph from descending colon, pelvis and lower limbs through

inferior mesenteric and common iliac lymph nodes– Preaortic lymph nodes

• Celiac and mesenteric nodes• Form intestinal lymphatic trunks which give rise to thoracic duct

– Chyle cistern• Thin-walled sac at inferior end of thoracic duct• Variable in size and shape

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A = ascending colon

C = cecum

D = descending colon

G = sigmoid colon

H = hepatic (right) colic flexure

R = rectum

S = splenic (left) colic flexure

T = transverse colon

U = haustra

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A = ascending colonC = cecumD = descending colonG = sigmoid colonH = hepatic (right) colic flexureR = rectumS = splenic (left) colic flexureT = transverse colonU = haustra

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