Accessory obturator nerve

The Accessory Obturator Nerve is present in about 29 per cent. of cases.

It is of small size, and arises from the ventral divisions of the third and fourth lumbar nerves.

It descends along the medial border of the Psoas major, crosses the superior ramus of the pubis, and passes under the Pectineus, where it divides into numerous branches.

One of these supplies the Pectineus, penetrating its deep surface, another is distributed to the hip-joint; while a third communicates with the anterior branch of the obturator nerve.

Occasionally the accessory obturator nerve is very small and is lost in the capsule of the hip-joint.

When it is absent, the hip-joint receives two branches from the obturator nerve.