Reproductive Anatomy

Question 1

Greater (false) pelvis vs Lesser (true) pelvis

Answer 1

Greater = between iliac crests and superior to pelvic inlet
- houses the abdominal viscera

Lesser = between pelvic inlet and outlet
- houses the reproductive and urinary organs

Question 2

Muscles of the pelvic diaphragm (floor)

Answer 2

Puborectalis, pubococcygeus and iliococcygeus (combined = levator ani)

Coccygeus

Question 3

Muscles of the pelvic wall

Answer 3

Obturator internus and piriformis muscles

Question 4

What is the perineum

Answer 4

Shallow compartment inferior to pelvic diaphragm
- purpose is to anchor external genitalia and provide outlet for anus, urethra, vagina

Composed of two “triangle” shaped compartments split by a horizontal line between ischial tuberosities

• anal triangle
• urogential triangle

Muscles of the perineum

• bulbospongiousus (surround bulb of penis and clit)
• ischiocavernosus (surrounds cura of penis and clit)
• deep and superficial transverse muscle RS
• external urethral sphincter and external anal sphincter
• also contains the “perineal body” which is a central tendon of the perineum that anchors
• bulbospongious, external anal sphincter, superficial and deep transverse perineal, external urethral sphincter, levator ani muscles

Question 5

Peritoneal folds and fossa

Answer 5

Occur when the peritoneum goes into the pelvic cavity but NOT to the pelvic floor

• drapes over the superb lateral surfaces of the pelvic viscera
• establishes the pelvic pain line (PPL)

Folds and fossa in both sexes
- supravesical fossa and paravesical fossa (surround the bladder)

Folds and fossa in males

• rectovesical pouch (between bladder and rectum)
• ureteric fold (equivalent to broad ligament)

Folds and fossa in females

• Vesico-uterine pouch
• recto-uterine pouch
• broad ligament
• ovarian ligaments
• mesovarium (attaches ovaries to broad ligament)
• mesosalphix (uterine tubes)
• mesomertium (uterus)

Question 6

Superficial fatty layer of the perineal fascia (subcutaneous)

Answer 6

Continuous with superfical fatty layer of the abdomen (campers fascia)

Continues with the anal triangle in both sexes

• continues into labia majors and mons pubis in females
• DOESNT enter the penile and scrotum of males

Question 7

Deep membranous layer of peritoneal fascia (subcutaneous)

Answer 7

Continues from collies fascia and attaches posteriorly to perineal membrane and perianal body, laterally to the TFL
- DOENST enter the anal triangle

Females and males = continues with scarpa fascia

In males this fascia continues into the scrotum and penile fascia (covers darts muscle)

Question 8

Contents of the superficial perineal pouch

Answer 8

is a potential space between perineal fascia and the perineal membrane

Females:
- clitoris, vestibular bulbs, ischiocavernosus, bulbosponiosus muscles, greater vestibular glands, internal pudenedal vessels and the pudendal nerve

Males:

• bulb and cura of the penis
• ischiocavernosus and bulbosponiosus muscles
• spongy urethra, internal pudendal vessels
• pudendal nerve

Question 9

Contents of the deep perineal pouch

Answer 9

Potential space between perineal membrane and inferior fascia of the pelvic diaphragm

Females

• proximal and external urethral sphincter
• internal pudendal vessels
• pudendal nerve

Males:

• intermediate urethra
• external urethral sphincter
• deep transverse perineal muscle
• pudendal nerve and vessels
• bulbo-urethral glands

Question 10

Review of the pudendal nerve

Answer 10

S2-S4 and is the major nerve of the perineum

Has three branches
1) inferior rectal nerve: controls external anal sphincter and the sensation of anal canal inferior to pectinate line

2) perineal nerve: controls muscles of the perineum (except external urethral sphincter). Sensation to vaginal vestibule and inferior 1/4 vaginal canal
- also posterior scrotum, labia majora/minora

3) dorsal nerve of the penis/clit: sensation to the skin/prepuce/glands
- also controls the external urethral sphincter

Question 11

Other nerves of the perineum

Answer 11

Ilio-inguinal nerve

• L1 root
• sensation of the root of the penis, anterior scrotum and anterior labia majora

Genitofemoral nerve

• L1/L2 roots
• sensation to anterior scrotum and labia majora

Posterior cutaneous branch of the thigh

• S1/2/3 roots
• sensation to the posterior scrotum and labia majora

Cavernous nerve
- parasympathetic nerve that controls the helicine arteries in erectile tissues

Question 12

Sympathetic innervation to the pelvis and perineum

Answer 12

T10-L2 nerve roots

Induces vasoconstriction when needed

Control peristalsis in the ductus defers, seminal vesicles, ejaculatory ducts, prostate

Contracts internal urethral sphincter in males

Controls ejaculation

Relaxes detrusor

Question 13

Parasympathetic innervation to the pelvis and peritoneum

Answer 13

Pelvic splanchnic nerves (S2-S4 anterior rami)

Relaxes the internal urethral sphincter in males

Induces vasodilation and engorgement of the erectile tissues

Relaxes the detrusor muscle

Question 14

Superior hypogastric plexus

Answer 14

Network of mostly post-synaptic sympathetic fibers and visceral afferent fibers

• also carries presynaptic fibers from lumbar splanchnic nerves (but doesnt control them)
• receives the two lower lumbar splanchnic nerves

Occurs inferior to the aortic bifurcation

Divides into the left and right hypogastric nerves

Question 15

Inferior hypogastric plexus

Answer 15

Network of pre and post synaptic sympathetic as well as pre and post synaptic parasympathetic fibers

Formed from the fusion of hypogastric,pelvic splanchnic and sacral splanchnic nerves

Controls the majority of the sympathetic and parasympathetic innervation to the pelvic contents

Question 16

Pelvic pain line (PPL)

Answer 16

Visceral Afferent pain fibers superior to the PPL follow sympathetic pathways

Visceral afferent pain fibers inferior to the PPL follow parasympathetic pathways

Question 17

Arterial supply to the pelvic cavity

Answer 17

Major artery is the internal iliac artery
- divides into anterior and posterior trunks

Posterior trunk
1) iliolumbar artery = supplies muscles of the posterior abdominal wall, illiacus and ilum

2) lateral sacral artery = supplies spinal meninges of the lumbar and sacral regions and the sacrum
3) superior gluteal artery = muscles and skin in the gluteal region

Anterior trunk
1) umbilical artery = supplies bladder and distal ureters (ductus deferens)

2) obturator artery = supplies adductor region of the thigh
3) inferior vesicle and vaginal arteries = supply bladder, ureter, seminal vesicles, prostate (male) and vagina (females)

4) uterine artery (ONLY IN FEMALES)
- courses within the broad ligament and passes under the ureter
- supplies the cervix, vagina, uterus, ovaries and uterine tubes

5) Middle rectal artery = supplies rectum
6) internal pudendal artery = majority of the skin and muscles within the anal and urogential triangles
7) inferior gluteal artery = skin and gluteal muscles and the posterior thigh

Question 18

Where do the testicular/ovarian artery originate from

Answer 18

Directly from the abdominal aorta

NOT of the internal iliac artery

Naturally supplies the ovaries and testicles

Question 19

Superior recital artery

Answer 19

Terminal branch off the inferior mesenteric artery to supply superior rectum

Question 20

Venous drainage of the pelvis/perineum

Answer 20

Majority drains into the internal iliac veins and moves up to the SVC

Right testicular/ovarian veins are directly attached to the IVC

Left testicular/ovarian veins are directly attached to the left renal vein

Question 21

How does lymph drain from the breast?

Answer 21

Superiolateral quadrant and central breast = axillary lymph nodes

Medial quadrants = parasternal lymph nodes or to the opposite breast

Inferior quadrants = abdominal lymph nodes

Question 22

Erection vs ejactulation

Answer 22

Erection

• is a parasympathetic action
• generates from the cavernous nerve relaxing smooth muscles of fibrous trabeculae within the corpora/crus/bulb of the penis and the coiled helicine arteries
• the bulbospongiosus and ischiocavernosus muscles contract, compressing the veins and preventing venous blood return

Ejactulation

• is a sympathetic action
• is a coordinated peristaltic contraction of the smooth muscles in the epididymis/ductus deferens/seminal vesicles/prostate deliver secretions to the prostatic urethra
• constriction of the internal urethral sphincter occurs which prevents reflux into he bladder
• bulbospongiosus muscle is contracted via pudendal nerve innervation helps compress the urethra and promotes emission

After ejactulation = smooth muscles relax and the helicine arteries relax

Question 23

Arterial supply to the penis

Answer 23

All branches are off the internal pudendal artery from the internal iliac artery

Dorsal arteries: supplies fibrosis tissue of the corpora cavernous, corpus spongiosum, spongy urethra, penile skin

Deep penile arteries (helicine arteries): within the corpora cavernous to supply erectile tissues

External pudendal artery = penile skin

Question 24

Venous drainage of the penis

Answer 24

All small veins join to the deep dorsal vein of the penis and drains into the he superfical dorsal veins -> superficial external pudendal vein -> IVC