GREAT VESELS OF THE GREAT VESELS OF THE ABDOMENABDOMEN

Abdominal AortaAbdominal Aorta

The thoracic aorta passes through the aortic hiatus to become the abdominal aorta and extends between the T12 – L4 vertebra levels

Abdominal aorta terminates at the aortic bifurcation by giving its two terminal branches, right and left common iliac arteries

Branches of the aorta are classified as unpaired and paired branches

Abdominal aortaAbdominal aorta

Can be compressed against vertebral column Can be compressed against vertebral column in children and thin adults at L4 level.in children and thin adults at L4 level.

• Celiac trunk– Left gastric artery

• Esophageal branches– Splenic (lienal artery)

• Short gastric aa• Posterior gastric• Pancreatic branches• Left gastroepiploic artery

– Common hepatic artery• Gastroduodenal artery

– Superior pancreaticoduodenal artery

– Right gastroepiploic artery• Proper hepatic artery

– Right gastric artery– Right and left hepatic aa

• Superior mesenteric artery– Inferior pancreaticoduodenal

artery– Jejunal branches– Ileal branches– Ileocolic artery

• Anterior and posterior caecal aa• Appendicular artery

– Right colic artery– Middle colic artery

• Inferior mesenteric artery– Left colic artery– Sigmoid aa– Superior rectal artery

Unpaired branches

• Middle sacral artery

(abdominal)Aortic aneurysm

• This angiogram picture shows a typical aortic aneurysm. As the aneurysm gets

larger, the risk of rupture increases greatly.

Clinical noteClinical note

As aorta lies posterior to the pancreas and As aorta lies posterior to the pancreas and stomach, tumors of these organs may stomach, tumors of these organs may transmit the pulsations of the aortatransmit the pulsations of the aorta, mimicking , mimicking an aneurysman aneurysm

•The two common iliac veins join at L5 to form IVC.

•IVC pierces(passes through) the diaphragm at T8 level

•Receives all the systemic veins from the abdomen except left gonadal and left supra renal veins

INFERIOR VENA CAVAINFERIOR VENA CAVA

TributariesTributaries

The two common iliac veinsThe two common iliac veinsRight gonadal veinRight gonadal veinBoth renal veinsBoth renal veinsRight suprarenal veinRight suprarenal vein Inferior phrenic veinsInferior phrenic veinsHepatic veinsHepatic veins

•In some instances the vena cava crosses anterior to (instead of posterior to) the ureter.It is called •pre-ureteric vena cava and may cause• ureteric obstruction

Extensive anastomoses among the caval, azygos, and vertebral systems provide multiple routes for the return of blood to the heart. In effect, the azygos and vertebral systems bypass the caval system.

POSTERIOR ABDOMINAL POSTERIOR ABDOMINAL WALLWALL

Bears the following structuresBears the following structures

Five lumbar vertebrae and intervertebral discs between themFive lumbar vertebrae and intervertebral discs between them

Posterior abdominal wall muscles; psoas, quadratus Posterior abdominal wall muscles; psoas, quadratus lumborum, iliacus, transverse and oblique abdominal lumborum, iliacus, transverse and oblique abdominal musclesmuscles

Part of diaphragmPart of diaphragm

Fascia, including the thoracolumbar fasciaFascia, including the thoracolumbar fascia

Lumbar plexus and its branchesLumbar plexus and its branches

Fat, lumbar sympathetic trunks, vessels (i.e. aorta, IVC) and Fat, lumbar sympathetic trunks, vessels (i.e. aorta, IVC) and lymph nodeslymph nodes

Posterior abdominal wallPosterior abdominal wall

The psoas sheath, attached to the lumbar The psoas sheath, attached to the lumbar transverse processes and bodies, allows transverse processes and bodies, allows the spread of infection (e.g., a tuberculous the spread of infection (e.g., a tuberculous abscess from a vertebral body) into the abscess from a vertebral body) into the thigh (psoas abscess). thigh (psoas abscess).

Lumbar plexusLumbar plexus L1 L1 L2 L2 L3 L3 L4 L4 L5 L5 L1 gives rise to the iliohypogastric and L1 gives rise to the iliohypogastric and

ilioinguinal nerves. ilioinguinal nerves. L1 + L2 gives rise to the genitofemoral nerve L1 + L2 gives rise to the genitofemoral nerve L2 + L3 gives rise to the lateral femoral L2 + L3 gives rise to the lateral femoral

cutaneous cutaneous L2 + L3 + L4 give rise to the femoral and L2 + L3 + L4 give rise to the femoral and

obturator nerves obturator nerves L4 + L5 give rise to the lumbosacral trunk which L4 + L5 give rise to the lumbosacral trunk which

joins sacral nerves to form the sacral plexus.joins sacral nerves to form the sacral plexus.

DIAPHRAGMDIAPHRAGM(dia = in between, phragma = partition)(dia = in between, phragma = partition)

Formed of skeletal musclesFormed of skeletal muscles

Muscle fibers converge at the center to form Muscle fibers converge at the center to form the central tendonthe central tendon

Lies between the thoracic and abdominal Lies between the thoracic and abdominal cavitiescavities

The chief muscle of inspirationThe chief muscle of inspiration

DIAPHRAGM (continued)DIAPHRAGM (continued)

PartsParts of the diaphragm of the diaphragm

Central tendonCentral tendon (has no bony attachments) (has no bony attachments)

Right and left domesRight and left domes

Strenal partStrenal part (attaches to the xiphoid process) (attaches to the xiphoid process)

Costal partCostal part (attaches to the inferior six ribs) (attaches to the inferior six ribs)

Lumbar partLumbar part (forms the and right and left crura, (forms the and right and left crura, lateral attachlateral attachments are throughments are through the medial and the medial and lateral arcuate ligaments)lateral arcuate ligaments)

DIAPHRAGM (continued)DIAPHRAGM (continued)

ArteriesArteries

-- Pericardiophrenic and musculophrenic arteriesPericardiophrenic and musculophrenic arteries (from (from the internal thoracic artery)the internal thoracic artery)

-- Superior phrenic arteriesSuperior phrenic arteries (branches of the thoracic (branches of the thoracic aorta)aorta)

-- Inferior phrenic arteriesInferior phrenic arteries (first branches of the (first branches of the abdominal aorta)abdominal aorta)

VeinsVeins

-- Follow the arteries of same nameFollow the arteries of same name

DIAPHRAGM (continued)DIAPHRAGM (continued)

LymphaticsLymphatics

-- Drain into the parasternal, posterior mediastinal and Drain into the parasternal, posterior mediastinal and phrenic lymph nodesphrenic lymph nodes

NervesNerves

-- Phrenic nervesPhrenic nerves (from the cervical plexus) (from the cervical plexus)

DIAPHRAGM (continued)DIAPHRAGM (continued)

Diaphragmatic aperturesDiaphragmatic apertures

Caval openingCaval opening

- Transmits the IVC and right phrenic nerveTransmits the IVC and right phrenic nerve

Esophageal hiatusEsophageal hiatus

- Transmits the esophagus, anterior and posterior Transmits the esophagus, anterior and posterior vagal trunks, esophageal branches of the left gastric vagal trunks, esophageal branches of the left gastric vessels and some lymph vesselsvessels and some lymph vessels

Aortic hiatusAortic hiatus

- Transmits the aorta, thoracic duct- Transmits the aorta, thoracic duct, and, and the azygos the azygos and and hemiazygos hemiazygos veinveinss

POSTERIOR ABDOMINAL WALL (continued)POSTERIOR ABDOMINAL WALL (continued)

Fascia of the posterior abdominal wallFascia of the posterior abdominal wall

-- Lies between the parietal peritoneum and the musclesLies between the parietal peritoneum and the muscles

- Continuous with the transversalis fascia laterallyContinuous with the transversalis fascia laterally

Parts of the fascia of the posterior abdominal wallParts of the fascia of the posterior abdominal wall

- Psoas fascia (covers the psoas muscle)Psoas fascia (covers the psoas muscle)

- Forms the medial arcuate ligaments on each sideForms the medial arcuate ligaments on each side

- Quadratus lumborum fascia (covers quadratus lumborum muscle)Quadratus lumborum fascia (covers quadratus lumborum muscle)

- Forms the lateral arcuate ligaments on each sideForms the lateral arcuate ligaments on each side

- Thoracolumbar fascia (medially splits into two and encloses the Thoracolumbar fascia (medially splits into two and encloses the deep back musclesdeep back muscles

- Laterally attaches to the internal oblique and transverse abdominal Laterally attaches to the internal oblique and transverse abdominal musclesmuscles

POSTERIOR ABDOMINAL WALL (continued)POSTERIOR ABDOMINAL WALL (continued)

LymphaticsLymphatics of the posterior abdominal of the posterior abdominal wallwall

Common iliac lymph nodesCommon iliac lymph nodes Lumbar (aortic) lymph nodesLumbar (aortic) lymph nodes Preaortic lymph nodes (celiac, superior Preaortic lymph nodes (celiac, superior

mesenteric and inferior mesenteric lymph nodes)mesenteric and inferior mesenteric lymph nodes) Efferent vessels from the preaortic lymph nodes Efferent vessels from the preaortic lymph nodes

form the intestinal lymphatic trunk and drain into form the intestinal lymphatic trunk and drain into the the cisterna chyle cisterna chyle (the begining of the (the begining of the thoracic duct)thoracic duct)