Pelvic musculature and nerves

10 April 2008

Pelvis - sagittal section

Ischial spine

Ischial tuberosity

Symphyseal surface

Arcuate line

Greater sciatic foramen

Lesser sciatic foramen

Netter 1997; pl. 330; 2003, pl. 340

Sexual dimorphism of pelvis

Examine angle between ischiopubic rami

Moore & Dalley, 2006 p.361

Urogenital diaphragm

Urethra

Inferior fascia of diaphragm

Deep transverse perineus

Superficial transverse perineus m.

Netter 1997, pl. 357; 2003, pl. 366

Muscles of Pelvic floor - medial view

Obturator internus

Coccygeus

Arcus tendineus

Iliococcygeus

Pubococcygeus

Piriformis

Netter 1997,; pl. 333-335; 2003, pl. 343-345

Pelvic Diaphragm

Coccygeus

Levator ani

Iliococcygeus

Pubococcygeus

Puborectalus

Urogential diaphragm and Piriformis are separate structures

Ischiorectal fossa

Netter 1997, pl. 364; 2003, pl. 373

Pelvic innervation is a mixture of autonomic, somatic motor, visceral sensory and somatic sensory.

Parasympathetic and sympathetic systems control smooth muscle in the pelvis, but are also in a delicate balance of control over blood flow and through it much of the function of pelvic and perineal structures.

Lumbar plexus

Lateral femoral cutaneous n.

L2,3; posterior

Femoral n.

L2,3,4; posterior

Obturator n.

L2,3,4; anterior

Netter 1997, pl. 464; 2003, pl. 480

Sacral plexus

Superior gluteal n.

Inferior gluteal n.

N. to piriformis

Peroneal (fibular) part of sciatic n.

Tibial part of sciatic n.

Pudendal n.

Netter 1997, pl. 465; 2003, pl. 481

Pudendal n.

Greater sciatic foramen

Ischiorectal fossa

Netter 1997, pl. 382; 2003, pl. 391

Summary of Pelvic & Perineal Innervation

Somatic motor

Urogenital & Pelvic diaphragms - S-2,3,4

Perineal n. (from Pudendal) - perineal muscles

Somatic sensory

Ilioinguinal n. & Genital banch of Genitofemoral

Pudendal n.

Perineal branch of Posterior femoral cutaneous

Visceral motor - sympathetic

Inferior hypogastric plexus - uterus, vagina, bladder, ductus deferens, prostate

Superior rectal plexus

Ovarian plexus

Sacral sympathetic trunks - gray rami to sacral nn

Visceral motor - parasympathetic

Pelvic splanchnic nn. - nervi erigentes within inferior hypogastric plexus

Netter 1997, plate 380, 383; 2003, pl. 389, 392

Visceral sensory

Inferior hypogastric plexus to superior

hypogastric plexus- uterus, vagina

with Pelvic splanchnics to S2-4 - bladder,

ductus deferens, prostate, rectum