Obturator Nerve

There are reports of several variations in the formation, course, and distribution of this nerve. The contribution to the nerve from the second lumbar nerve may be absent. Branches from the obturator to the following structures have been reported: mm. obturator internus, and pectineus, the obturator artery, the periosteum of the pelvic surface of os pubis. Both the anterior and posterior branches of the nerve may pass posterior to adductor brevis.

The branch from the main trunk of the nerve to obturator externus may pass to the lateral (instead of medial) side of the obturator nerve.

The obturator nerve may have additional roots from the first or fifth lumbar nerves. The cutaneous branch is frequently absent.

An accessory obturator nerve has a reported incidence of 29%, 13%, or 8% according to different authors. It arises from the third or more commonly the third and fourth lumbar nerves between the roots of the femoral and obturator nerves. The accessory nerve may also arise from L2,L3 and L4; L2,L3; or L3; or it may arise from the obturator nerve. Although it may be closely related to the femoral nerve, it usually courses with the obturator to the level of the pelvic brim, but instead of passing through the obturator foramen, it descends along the medial border of the psoas muscle, crosses the anterior brim of the pelvis, passes beneath m. pectineus, and terminates in three branches, which are also variable. These branches supply the pectineus, the hip joint, and, by rejoining the obturator, the adductor muscles. The terminal branches, individually, usually replace the femoral branch to pectineus and usually supply the hip joint. They may, however, only supply m. pectineus or they may make a significant contribution to the innervation of the adductor muscles.

Riferimenti dell’opera originale

Elenco riportato come compare nella fonte, senza normalizzazione dei formati bibliografici.

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