Reproductive Anatomy Flashcards
Greater (false) pelvis vs Lesser (true) pelvis
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
Muscles of the pelvic diaphragm (floor)
Puborectalis, pubococcygeus and iliococcygeus (combined = levator ani)
Coccygeus
Muscles of the pelvic wall
Obturator internus and piriformis muscles
What is the perineum
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
Peritoneal folds and fossa
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)
Superficial fatty layer of the perineal fascia (subcutaneous)
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
Deep membranous layer of peritoneal fascia (subcutaneous)
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)
Contents of the superficial perineal pouch
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
Contents of the deep perineal pouch
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
Review of the pudendal nerve
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
Other nerves of the perineum
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
Sympathetic innervation to the pelvis and perineum
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
Parasympathetic innervation to the pelvis and peritoneum
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
Superior hypogastric plexus
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
Inferior hypogastric plexus
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
Pelvic pain line (PPL)
Visceral Afferent pain fibers superior to the PPL follow sympathetic pathways
Visceral afferent pain fibers inferior to the PPL follow parasympathetic pathways
Arterial supply to the pelvic cavity
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
Where do the testicular/ovarian artery originate from
Directly from the abdominal aorta
NOT of the internal iliac artery
Naturally supplies the ovaries and testicles
Superior recital artery
Terminal branch off the inferior mesenteric artery to supply superior rectum
Venous drainage of the pelvis/perineum
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
How does lymph drain from the breast?
Superiolateral quadrant and central breast = axillary lymph nodes
Medial quadrants = parasternal lymph nodes or to the opposite breast
Inferior quadrants = abdominal lymph nodes
Erection vs ejactulation
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
Arterial supply to the penis
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
Venous drainage of the penis
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
