42. Blood Supply, Lymphatic Drainage, and Nerves of the Pelvis 2024

What is the main artery that supplies the structures of the pelvis?

Internal iliac artery

Into what two divisions does the internal iliac artery bifurcate?

Anterior division and posterior division

Which artery supplies the superior aspect of the bladder?

Superior vesical artery

Which artery supplies the inferior aspect of the bladder and prostate in males?

Inferior vesical artery

Which pelvic artery is a remnant of the fetal umbilical artery?

Umbilical artery

Which artery supplies the uterus?

Uterine artery

Which artery supplies the vagina?

Vaginal artery

Which artery supplies the middle portion of the rectum?

Middle rectal artery

Which artery supplies the obturator canal and medial thigh?

Obturator artery

Which artery supplies the perineum and external genitalia?

Internal pudendal artery

Which artery supplies the gluteal region below the piriformis?

Inferior gluteal artery

Which artery supplies the gluteal region above the piriformis?

Superior gluteal artery

Which artery ascends to supply the iliacus and psoas muscles?

Iliolumbar artery

Which artery passes through the anterior sacral foramina?

Lateral sacral artery

What is the mnemonic for branches of the posterior division of the internal iliac artery?

PILLS G

What does "PILLS G" stand for?

Posterior division - Iliolumbar, Lateral sacral, Superior gluteal

Which arteries branch directly off the aorta to supply pelvic structures?

Gonadal arteries, median sacral artery, superior rectal artery

What is the arterial supply to the rectum from the aorta?

Superior rectal artery

Where do pelvic venous plexuses lie?

On the surfaces of pelvic organs

What is the clinical significance of pelvic venous plexuses?

They form portacaval anastomoses and communicate with the vertebral plexus

What is the name of the venous communication between rectal veins and systemic circulation?

Portacaval anastomosis

Which veins form an open communication with the internal vertebral plexus?

Lateral sacral veins

What are the two main components of pelvic innervation?

Somatic nerves and autonomic nerves

Which plexus provides somatic innervation to the pelvis?

Sacral plexus

Which spinal nerve levels contribute to the sacral plexus?

L4–S4

What nerve arises from L4–L5 and joins the sacral plexus?

Lumbosacral trunk

What is the major nerve of the sacral plexus that exits below the piriformis?

Sciatic nerve

What nerve supplies motor innervation to pelvic floor muscles?

Pudendal nerve

Through which foramen does the pudendal nerve exit the pelvis?

Greater sciatic foramen

Through which foramen does the pudendal nerve re-enter the perineum?

Lesser sciatic foramen

What are the two divisions of the autonomic nervous system in the pelvis?

Sympathetic and parasympathetic

Where do pelvic sympathetic nerves originate?

Thoracolumbar spinal cord (T11–L2)

Where do pelvic parasympathetic nerves originate?

Sacral spinal cord (S2–S4)

What is the function of pelvic sympathetic nerves?

Vasoconstriction, ejaculation, contraction of internal sphincters

What is the function of pelvic parasympathetic nerves?

Vasodilation, erection, relaxation of internal sphincters

What is the name of the nerve plexus formed by autonomic nerves in the pelvis?

Inferior hypogastric plexus

Which autonomic system is responsible for erection?

Parasympathetic (S2–S4, pelvic splanchnic nerves)

Which autonomic system is responsible for ejaculation?

Sympathetic (T11–L2)

Where does lymph from pelvic organs generally drain first?

Internal iliac lymph nodes

Where does lymph from deep perineum and glans penis/clitoris drain?

Deep inguinal lymph nodes

Where does lymph from the superficial perineum drain?

Superficial inguinal lymph nodes

Where does lymph from ovaries and testes drain?

Lumbar (para-aortic) lymph nodes

What is the clinical relevance of understanding pelvic lymphatic drainage?

Helps track cancer metastasis and infection pathways