Obturator Nerve

Origin

The obturator nerve is a branch of the lumbar plexus, which is formed within the psoas major muscle, by the union of the anterior divisions of the anterior rami of the second to fourth lumbar nerves (L2—L4).

Course

Following its origin, the obturator nerve descends through the substance of psoas major muscle. It emerges from the medial side of the muscle, near the pelvic brim, and enters the pelvic cavity.

The obturator nerve descends posterior to the common iliac vessels and continues to move across the lateral wall of the pelvic cavity until it reaches the obturator canal. Here it divides into anterior and posterior branches. The anterior and posterior branches gain access to the medial compartment of the thigh through the obturator canal (Jankovic and Peng, 2015).

Branches

The posterior branch descends posterior to adductor brevis and anterior surface of adductor magnus. The anterior branch descends on the anterior surface of the adductor brevis, posterior to the pectineus and adductor longus.

Supplied Structures

The posterior branch gives off muscular branches to obturator externus (L3-L4), adductor brevis (L2-L3), and part of adductor magnus (L2-L4). In addition, articular branches are given to the knee joint.

The anterior branch gives off muscular branches to the adductor longus (L2—L4), gracilis (L2-L3), adductor brevis (L2-L3), and pectineus (L2-L3) muscles. Cutaneous branches provide sensory innervation to the skin on the medial side of the thigh. In addition, articular branches are given off to the hip joint (Hanna, 2015).

References

Hanna, A. S. (2015) Anatomy and Exposures of Spinal Nerves. Springer International Publishing.

Jankovic, D. and Peng, P. (2015) Regional Nerve Blocks in Anesthesia and Pain Therapy: Traditional and Ultrasound-Guided Techniques. Springer International Publishing.