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