Exam V: Nerves and Arteries Flashcards
Sacral Plexus
Lumbosacral trunk: L4/L5 ONLY Ventral rami: S1-S4 Located anterior to piriformis Exit sacral foramina Obturator nerve: L2, L3, L4 (Lumbar plexus)
Sacral Plexus
Nerve: spinal cord segments Pudendal: S2-4 Nerve to levator ani, coccygeus, external anal sphincter: S4 Nerve to piriformis: S2 Sciatic: L4-S3 Superior Gluteal: L4-S1 Inferior Gluteal: L5-S2 Pelvic Splanchnic: S2-4 (parasympathetic fibers from lateral horn)
Pudendal Nerve
S2, 3, 4
Supplies perineum
Exits greater sciatic foramen and enters perineum through lesser sciatic foramen
Travels in pudendal canal (obturator fascia)
Within canal branches
Pudendal: Deep Perineal Nerve
Perineal nerve – at UGD divides into superficial and deep branches
Deep perineal nerve: mainly muscular, transverse perinei (both), bulbospongiosus, ischiocavernosus
Supplies nerve to bulb that pierces bulbospongiosus and supplies corpus spongiosum and mucus membrane of urethrae
Pudendal: Superficial Perineal Nerve
Superficial perineal nerve: medial and lateral branches scrotal skin (labia majora) posterior scrotal nerves, enter and course through superficial space
Pudendal Nerve: Dorsal Nerve of Penis/Clitoris
runs along ischial and pubic rami within deep perineal space
branch to corpus cavernosum
pierces anterior fascia (of UGD)
runs between corpora cavernosa and pubic symphysis onto dorsum of penis (clitoris)
small branches distribute to glans penis (clitoris)
Does not supply skeletal muscle (unlike the inferior rectal and perineal nn.)
Pudendal Nerve Block
Ischial spine is the landmark via vaginal exam because pudendal nerve is along with sacrotuberous ligament
Inject in nerve before it branches off
Internal Iliac Branches
Anterior division: Umbilical Obturator (unless aberrant) Uterine (female only) Vaginal (F) / Vesicle (M) Internal Pudendal Inferior Gluteal Middle Rectal
Posterior division:
Iliolumbar
Lateral sacral
Superior gluteal
Internal Iliac Posterior Trunk Branches
Iliolumbar: ascends out of pelvis and divides into iliac and lumbar branches
Lateral sacral: Course along posterior pelvic wall
Superior gluteal: Passes between lumbosacral trunk and S1 through GSF
Internal Iliac Anterior Trunk Branches
Umbilical artery usually 1st branch
Superior vesical
Inferior vesical: fundus of the bladder, prostate and seminal vesical (vaginal artery)
Middle rectal: rectum but also supplies the seminal vesicals and prostate
Obturator (variable)
Internal pudendal
Inferior gluteal passes between S1 and S2 or S2 and S3 (large)
Aberrant Obturator Branch
Aberrant Obturator artery when comes off something else other than anterior trunk of internal iliac
Comes off external iliac in this case, that goes over the pelvic rim into the obturator canal
Female Internal Genitalia Blood Supply
Uterine – arises from anterior trunk, runs on surface of levator ani toward uterine cervix between layers of broad ligament; crosses over ureter
Vaginal – directly from internal iliac or uterine artery; corresponds to inferior vesical artery (male) and supplies vagina, inferior region of bladder and pelvic part of urethra
Male Pelvic Organs Blood Supply
Superior vesicle to bladder
Inferior vesicle that supplies fundus f bladder, seminal vesciles, and prostate
Prostate – internal pudendal
Middle rectal - rectum
Pelvic Viscera Venous Drainage
Tributaries of internal iliac vein correspond to arteries.
Superior gluteal Inferior gluteal Internal pudendal Obturator Lateral Sacral Middle Rectal Vesical Uterine Vaginal
No UMBILICAL
Venous Draining of Penis
Superficial dorsal veins drain skin and prepuce of penis. Dump into superficial external pudendal vein.
Deep dorsal vein lies beneath Buck’s fascia, but superficial to tunica albuginea. Drains glans and corpora cavernosa via deep veins. Passes between two parts of suspensory ligament of penis and dumps into prostatic plexus
Pelvic Venous Plexus
Venous networks surround pelvic organs, anastomose with each other.
Pelvic venous plexuses are interconnected and drain into internal iliac vein, superior rectal to inferior mesenteric and to vertebral venous plexus (Batson’s plexus)
Connects to internal and external venous plexus – prostatic venous plexus; cancer cells can go to pre vertebral plexus and into the vertebral column (internal vertebral plexus?)
Also can carry to brain if goes higher up
Rectum Blood Supply
Superior rectal artery coming from IMA; portal system so can get portal hypertension in that area
Middle rectal from internal iliac and goes to caval system
Inferior rectal coming from internal pudendal and goes to caval system
*All anastomose with each other
Venous Drainage of Rectum: Hemorrhoids
When you have portal hypertension or cirrhosis the veins will dilate because the blood flow isn’t good
Internal rectal dilate = hemorrhoids
External rectal dilate from pregnancy and other pressures like constipation = hemorrhiods
Internal vs. External Hemorrhoids
Internal hemorrhoids:
Prolapse of anal mucosa which contain dilated veins from internal rectal venous plexus
Portal hypertension
Hepatic cirrhosis
Not painful because visceral innervation in this area
External hemorrhoids:
Blood clots in the external rectal venous plexus, covered by skin
Pregnancy, constipation
Painful
Anal Canal Blood Supply
Above pectinate line from superior and middle rectal, Below the pectinate line middle and inferior rectal artery
Ureter Blood Supply
renal, testicular, branches from the internal iliac and inferior vesical arteries
Bladder Blood Supply
superior, inferior vesical (uterine and vaginal in female)
Ductus Deferens Blood Supply
artery of the ductus deferens from the superior vesical artery
Seminal Vesicle Blood Supply
inferior vesical, middle rectal
Prostate Blood Supply
internal pudendal, inferior vesical and middle rectal arteries
Ovary Blood Supply
ovarian from aorta
Uterine Tube Blood Supply
uterine and ovarian vessels
Uterus Blood Supply
uterine and ovarian vessels
Vagina Blood Supply
vaginal artery (from uterine), inferior vesical and middle rectal
Male Urethra Blood Supply
urethral artery from internal pudendal
Female Urethra Blood Supply
inferior vesical and internal pudendal
Testes Blood Supply
testicular artery
Penis Blood Supply
internal pudendal
