Marilyn Rose

Formed by the sacrum, coccyx and two os caxae/ innominate bones Sacrum-5 fused vertebral segments

▪ First segment▪ sacral promontory- landmark-separates abdominal

cavity/ pelvic cavity▪ The 5 segment transverse processes combine to

form the lateral mass or ala(sacral foramina= nerve passageway) articulates with the os coxae @ the sacroiliac joints

▪ The fifth segment articulates with the coxxyx (3-5) small fused bony segments.

3 bones- ilium, pubis and ishium Ilium- larges, superior-

ala- iliac fossa▪ Superior ridge of the ala=

iliac crest

▪ Slopes down to form ASIS and AIIS

▪ Body of the ilium creates the upper acetabulum, which articulates with the femoral head

Pubis- pubic bone Forms the lower

anterior acetabulum

Body, superior and inferior pubic rami

Bodies of the two pubic bones form the-symphysis pubis

Ischium- inferior os caxae Body and two rami Body- forms

lower,posterior acetabulum Sup ramus-

posterior/inferior ▪ forms ischial tuberosity

Inf ramus- anterior, medial▪ Forms ischial spine

Union of the pubic rami and ishium surrounds the obturatior foramen- obturator muscles pass

False/ Greater Pelvis Above the pelvic brim

True/Lesser Pelvis Below pelvic brim

Pelvic Inlet Superior- true pelvis- sacral

promontory to the crest of the pubic bone.

Pelvic Outlet Inferior- tip of coccyx to

inferior margin of pub symphysis or between the ischial tuberosities.

osteosarcoma of the ilium

MaleFemale

Extra-pelvic Rectus abdominis- ant abd Psoas-lat L spine External/internal oblique- lat

abdomen- ribs-iliac crest Hip muscles:

▪ Gluteus- maximus, medius, minimus- ▪ abduct, rotate, extend the thigh

Pelvic Wall Piriformis-ilium to > troch Obturator internus- pubic

bone to > troch Obturator externus Iliacus + psoas= iliopsoas

▪ To <<< troch▪ Makes walking possible!!!

Pelvic diaphragm •Majority of the pelvic floor•Levator ani- sym pub-ischial spine to coccyx•Coccygeus- posterior floor- ischial spine- coccyx

Psoas (8)

Maximus (24) and medius (25)Rectus abdominus (10)

Obturator internus/exturnus (39,40)

Ishial Tuberosity (44)

Descending AO- bifurcates at L4 into RT/LT common iliac arteries Each common bifurcates

into Internal/External iliac arteries▪ Internal iliac- smaller- supplies

O2 blood to pelvis▪ External iliac- larger- extends

along pelvic brim and exits the iliac fossa and supplies arterial blood to the leg(s)▪ External iliac becomes the femoral

artery at the ASIS! ▪ Wow! A handy landmark!!!

External iliac Common femoral

Internal iliac veins-main drainage for pelvis Superior rectal, median sacral and gonadal also are

present Ascend pelvis medial to internal iliac artery Venous plexuses drain into the internal iliac vein External iliac- extension of of femoral- return blood from

legs Medial to external iliac artery Move posteriorly as they join common iliac vein at SI joint

Common iliac vein- posterior to common iliac from the junction of int/ext iliacs

IVC at L5 right of midline- after the union of the common iliac veins

Key:

#1 = L5#2 = Ascending Colon#3 = Descending Colon#4 = Ureters (left & right)#5 = Iliac Crest#6 = Gluteus Medius#7 = Iliacus Muscle#8 = Psoas Muscle#9 = Rectus Abdominis#10 = Common Iliac Arteries#11 = Common Iliac Veins

CFA/V- #20Troch- #37Ischial spine- #35Rectum- #30Prostate-#32

Rests on pelvic floor -posterior to symphysis pubis

Neck of the bladder- internal urethral sphincter (bladder control)

Trigone= openings in the floor of the bladder- ureters and urethra Female urethra- 3-4 cm-

external opening Male urethra- 18-20 cm-

▪ Prostatic, membranous and penile urethra

▪ Dual function

Terminal portion of the large intestine S3- to tip of coccyx- 15 cm in length Anteroposterior curve (sacral flexure)

of sacrum and then ends by turning inferiorly/ anteriorly to become anal canal (perineal flexure)

Between two flexures is the transverse rectal fold- Kohlrausch’s fold- 5-8 cm from anus. Landmark for males prostate exam

and the vault of the vagina in females

Involuntary internal anal sphincter and voluntary external anal sphincter

Sex hormones, ova and protect and support a developing embryo

Uterus, ovaries, fallopian tubes, vagina Uterus-

▪ endometrium, myometrium and perimetrium

Stabilized by suspensory ligaments- ▪ Round, uterosacral and lateral cervical

ligaments Broad ligament-(peritoneal fold) -

encloses the ovaries, fallopian tubes and uterus

Two pouches- areas where fluid can accumulate▪ Vesicouterine pouch- btw ut and post wall

of bladder▪ Rectouterine pouch (pouch of Douglas)-

posterior, between uterus and rectum

Ovaries- paired on each side of uterus

Fallopian tubes- muscular tubes extending laterally form body of UT to peritoneum-supported by broad lig

Vagina- anteroinferiorly from cervix of UT to external vaginal orifice- between bladder and rectum

Organs- testis, epididymis, vas deferens, ejaculatory duct, seminal vesicle,

prostate gland, bulbourethral gland (Cowper’s) and penis All structures except testes and penis are located within pelvic

cavity. Scrotum-

pouch that encloses the testis, epididymis and lower spermatic cord- the epididymis is tightly coiled tubular structure at the superoposterior surface of each testis-composed of a head, body and tail.

Vas deferens and ejaculatory duct- Posterior spermatic cord- courses up inguinal canal and over ureter

into and into the posterior surface of the bladder- it joins with the duct of the seminal vesicle to form the ejaculatory duct which empties into the prostatic urethra

Seminal vesicles- paired glands lateral to vas deferens and on the posterior/inferior surface of the bladder-superior to the prostate

Penis- made of 3 cylindric tissues bundles- 2 corpora cavernosa and one

corpus spongiosum

1, sartorius m. 2, femoral a. 3,femoral v. 4, left pectineus m. 5, pubis 6, symphysis pubis 7, spermatic cord 8, right pectineus m. 9, obturator internus

m. 10, gemellus inferior m.

  

1, rectus abdominis m. 2, bladder 3, pubis 4, ischium 5, testis 6,

corpus cavernosum

1, rectus abdominis m. 2, symphysis pubis 3, corpus cavernosum 4, corpus spongiosum 5,

prostate 6, bladder 7,seminal vesicle 8, rectum 9, sacrum

Largest accessory gland of male reproductive system- secretes seminal fluid

Inferior to the bladder and surrounds the prosthetic urethra

Base- adjacent to the bladder neck

Apex- urogenital diaphragm

Two lateral lobes, middle lobe and anterior fibromuscular portion- 4 zones

Second most common cancer in men over 55

Axial T2-weighted image obtained through the midprostate

shows the prostatic urethra (P) in the posterior prostate

Normal MR imaging anatomy of the male urethra in a 59-year-old man.

prostatic urethra (P) in the posterior prostate

bulbous urethra (B) traversing the midline within the corpus spongiosum

Nodal chainsCorrespond to pelvic vessels

Obturator nodes- along midpoint of obturator internus muscle

Internal/External nodes Sacral nodes Inguinal nodes

Pelvic nodes are pathologically enlarged when they exceed 10 mm in short axis