CHAPTER 12 Spinal Cord and Spinal Nerves

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Obturator Nerve

Origin

Lumbosacral plexus, L2–L4

Movements/Muscles Innervated Rotates thigh laterally

Obturator externus

Obturator nerve

Adducts thigh

Adductor magnus (adductor part)Adductor longusAdductor brevis

Adducts thigh and flexes knee

Gracilis

Cutaneous (Sensory) Innervation Superior medial side of thigh

FIGURE 12.24 Obturator Nerve

The route of the obturator nerve and the muscles it inner-vates. The inset depicts the cutaneous (sensory) distributionof the nerve ( blue area ).

Medial view

Anterior view

cutaneous distribution of the common fibular nerve and itsbranches is the lateral and anterior leg and the dorsum of the foot(figure 12.27).

Other Lumbosacral Plexus Nerves

In addition to the nerves just described, the lumbosacral plexusgives rise to gluteal nerves, which supply the hip muscles that acton the femur, and the pudendal (p ū -den′d ă l) nerve, which sup-plies the muscles of the abdominal floor (see figure 12.23).

The  iliohypogastric (il′ ē - ō -h ī -p ō -gas′trik), ilioinguinal (il′ ē - ō -ing′gwi-n ă l), genitofemoral (jen′i-t ō -fem′ ŏ -r ă l), cutane-ous femoral, and pudendal nerves innervate the skin of the supra-pubic area, the external genitalia, the superior medial thigh, andthe posterior thigh. The pudendal nerve plays a vital role in sexualstimulation and response. Branches of the pudendal nerve areanesthetized during childbirth before a doctor performs an episiotomy (e-piz- ē -ot′ ō -m ē , epis- ē -ot′ ō -m ē ), a cut in the perineumthat enlarges the opening of the birth canal.