perineum and pelvis ch summary

diamond-shaped space that has same boundaries as pelvic outlet or inferior aperture of pelvis

bounded by: pubic symphysis, ischiopubic rami, ischial tuberosities, sacrotuberous ligament, coccyx tip
divided into: urogenital and anal triangles

b/w inferior fascia of urogenital diaphragm (perineal membrane) and superficial perineal fascia (Colles' fascia)

perineal muscles
penis or clitoris crus
bulb of penis or vestibule
central tendon of perineum
greater vestibular glands in female
branches of internal pudendal vessels
pudendal n

b/w superior and inferior fasciae of urogenital diaphragm

deep transverse perineal muscle
sphincter urethrae
membranous part of urethra
bulbourethral glands in male
branches of internal pudendal vessels
pudendal n

separated by levator ani and fasciae
contains inferior rectal n and vessels and fat

anteriorly: sphincter urethrae and deep transverse perineal muscles
posteriorly: gluteus maximus nad sacrotuberous ligament
superomedially: sphincter ani externus and levator ani
laterally: obturator fascia covering obturator internus
floor: skin

sac of skin w/ no fat, w/ dartos muscle (fascia)
continuous w/ superficial penile fascia and superficial perineal fascia
contains testis and epididymis

blood from external and internal pudendal aa
innerv by anterior scrotal branch of ilioinguinal n
genital branch of genitofemoral n
posterior scrotal branch of perineal branch of pudendal n
perineal branch of posterior femoral cutaneous n

superficial inguinal nodes

dartos muscle, cremaster muscle, pampiniform plexus
dartos: wrinkles scrotal skin to increase thickness and reduce heat loss
cremaster: elevates testes

root: 2 crura + penis bulb + body
contains 1 corpus spongiosum + 2 corpora cavernosa
head = glans penis, which is made by terminal part of corpus spongiosum

2 longitudinal skin folds that are homologous to scrotum and have terminations of round ligaments of uterus

hairless
have no fat
divided into upper lateral part and lower medial part

upper lateral: fuses above clitoris to form clitoris prepuce
lower medial: fuses below clitoris to form clitoris frenulum

space b/w labia minora and has openings for urethra, vagina and ducts of greater vestibular glands in its floor

penis and consists of 2 crura, 2 corpora cavernosa, 1 glans, but no corpus spongiosum
glans clitoris is made from corpora cavernosa and covered by sensitive epithelium

S2, S3, S4
passes thru greater sciatic foramen b/w piriformis and coccygeus muscles and enters perineum w/ internal pudendal vessels thru lesser sciatic foramen
pudendal n enters pudendal canal, gives rise to inferior rectal and perineal nn and terminates as dorsal n of penis or clitoris

innerv sphincter ani externus and skin around anus

deep branch: supplies all perineal muscles
superficial (posterior scrotal or labial) branch: supplies scrotum or labia majora

runs b/w 2 layers of suspensory ligament of penis or clitoris and runs deep to deep fascia on dorsum of penis or clitoris to innerv skin, prepuce, and glans

friend= pudendal n that runs w/ it
leaves pelvis by grtr sciatic foramen and enters perineum thru lesser sciatic foramen
gives rise to inferior rectal, perineal, urethral aa and a of bulb, deep a of penis or clitoris, and dorsal a of penis or clitoris

comes from lower part of prostatic venous plexus in male or vesical plexus in female
empties into internal iliac v by common trunk

unpaired v that begins behind glans and lies in dorsal midline deep to deep fascia and superficial to tunica albuginea, leaves perineum thru gap b/w arcuate pubic ligament and transverse perineal ligament, and drains into prostatic and pelvic venous plexuses

runs towards pubic symphysis and terminates in external (superficial) pudendal vv, which drain into greater saphenous v

runs in median plane b/w left and right dorsal aa
ends in lower part of vesical venous plexus

basin shaped ring of bone formed by 2 hip bones, sacrum and coccyx
hip or coxal bone consists of ilium, ischium, pubis
divided by pelvic brim into pelvis major (false) above and pelvis minor (true pelvis) below

formed by levator ani and coccygeus, forms pelvic floor and supports pelvic viscera
flexes anorectal canal during defecation, helps voluntary control of micturition, helps direct fetal head toward birth canal at parturition

extends from uterus to lateral pelvic wall
holds uterus in position
contains uterine tube, uterine vessels, round ligament of uterus, ovarian ligament, ureter, nerve plexus, and lymphatic vessels
**does NOT contain ovary, but gives attachment to ovary thru mesovarium

remains of lower part of gubernaculum
keeps uterus anteverted and anteflexed
runs w/i broad ligament
enters inguinal canal at deep inguinal ring, emerges from superficial inguinal ring, becomes lost in labium majus

extends from ovary to uterus below uterine tube w/i layers of broad ligament

extends from cervix and vagina to pelvic wall and contains smooth muscle fibers
supports uterus

@ origin where pelvis of ureter joins ureter
where it crosses pelvic brim
@ junc w/ urinary bladder

accompanied by uterine artery
sometimes ureter injured by clamp in surgical procedures and may be ligated and sectioned by mistake during hysterectomy
remember: water (ureter) runs under the bridge (uterine artery)

passes posterior and inferior to ductus deferens and lies in front of the seminal vesicle
courses obliquely thru bladder wall and funcs as check valve to prevent reflux of urine into ureter

uvula = small rounded elevation just behind urethral orifice at trigone apex
trigone is bounded by 2 orifices of ureters and internal urethral orifice, around which is thick circular layer called internal sphincter (sphincter vesicae)

smooth muscle: detrusor muscle of bladder

superior and inferior vesical aa
venous blood drained by prostatic or vesical plexus of vv, which empties into internal iliac v
innerv by n fibers from vesical and prostatic plexuses

urination
initiated by stimulating stretch receptors in detrusor muscle in bladder wall by inc volume of urine
afferent GVA impulses arise from stretch receptors in bladder wall and enter spinal cord (S2, S3, S4) via pelvic splanchnic nn

symp fibers induce relaxation of bladder wall and constrict internal sphincter, inhibiting emptying
parasymp fibers in pelvic splanchnic n induce detrusor muscle contraction and relaxation of internal sphincter, enhancing urge to void

voids when somatic motor fibers in pudendal n cause voluntar relaxation of external urethral sphincter
@ end: external urethral sphincter contracts, and bulbospongiosus muscles in male expel last few drops of urine from urethra

female: smaller, lighter, thinner
male: larger, heavier, thicker

female: transversely oval
male: heart shaped

female: larger
male: smaller

female: wider, shallower
male: narrower, deeper

female: larger, greater
male: smaller, lesser

female: shorter, wider
male: longer, narrower

female: oval or triangular
male: round

descends into scrotum retroperitoneally
covered by tunica albuginea
germ cells make sperm
Sertoli (sustentacular) cells make androgen binding protein and inhibin
interstitial (Leydig) cells secrete sex hormones
myoid cells help squeeze sperms thru tubules

supplies by testicular a from abdominal aorta
drained by vv of pampiniform plexi into IVC on right and renal v on left
lymph vessels ascend w/ testicular vessels and drain into lumbar (aortic) nodes

head, body, tail, convoluted duct
func: maturation and storage of spermatozoa in head and body and propulsion of spermatozoa into ductus deferens

enters pelvis at lateral side of inferior epigastric a; passes superior to ureter near bladder wall; dilated to become ampulla; joins seminal vesicle duct to form ejaculatory duct, which empties into prostatic urethra on seminal colliculus just lateral to prostatic utricle; transports and stores spermatozoa; during ejac, thick layers of smooth muscle in ductus deferens propels sperm into urethra by peristalsis

lobulated glandular strucs that lie inferior and lateral to ampullae of ductus deferens
contain sugar and other nutrients to nourish sperm, prostaglandins to stim uterus contraction so sperm can move thru female reproductive tract; substances to enhance sperm motility and suppress immune response against semen in females; enzymes that clot ejaculated semen in vagina and then liquefy it so that sperm can swim out
make alkaline constituent of seminal fluid, which has fructose and choline

at base of urinary bladder
secretion helps clot and then liquefy semen
has 5 lobes: including anterior lobe, middle lobe (prone to benign hypertrophy), lateral lobe, posterior lobe (prone to carcinomatous transformation)

point (parasymp)
shoot (symp)

almond shaped strucs that lie on lateral walls of pelvic cavity
suspended by suspensory and round ligaments
make oocytes or ova and steroid hormones

extends from uterus to ovary and consists of isthmus, ampulla, and infundibulum
fimbriated distal end creates currents, helping draw an ovulated oocyte into uterine tube

fundus, body, isthmus and cervix
supported by broad, transverse cervical (cardinal) and round ligaments and muscles of pelvic floor, which provide most imp support

wall: perimetrium, myometrium, endometrium
uterine cycle : menstrual, proliferative and secretory phases

menstrual and proliferative are shedding and then rebuilding of endometrium in 2 wks before ovulation
3rd phase: prepares endometrium to receive embryo in 2 wks after ovulation

extends b/w vestibule and cervix of uterus
excretory channel for products of menstruation, receives penis and semen during coitus, acts as birth canal
vaginal fornix = ring like recess around cervix tip in upper vagina

extends from sigmoid colon to anal canal
feces stored in ampulla, which is lower dilated part of rectum that lies above pelvic diaphragm

superior, middle, and inferior rectal aa
drains venous blood into portal venous system via superior rectal v and into caval system via middle and inferior rectal vv

upper 2/3 (visceral part): intestine
lower 1/3 (somatic part): perineum
*pectinate line (serrated line following anal valves) divides the 2

intermuscular (intersphincteric) groove b/w lower border of internal anal sphincter and subcutaneous part of external anal sphincter

above: columnar or cuboidal
below: stratified squamous

above: portal venous system
below: caval venous system

above: internal iliac nodes
below: superficial inguinal nodes

above: visceral sensory
below: somatic sensory

above: internal
below: external

symp: contracts sphincter vesicae
parasymp: relaxes sphincter vesicae; contracts detrusor muscle

symp: causes vasoconstriction and ejaculation; contracts uterus
parasymp: vasodilation and erection; relaxes uterus