What is the obturator nerve and where does it originate?

The obturator nerve is the primary nerve of the medial (adductor) compartment of the thigh. It originates from the ventral divisions of the anterior rami of L2, L3, and L4 spinal nerves, making it a branch of the lumbar plexus.

How does the obturator nerve enter the thigh?

The obturator nerve enters the thigh through the obturator canal, where it then divides into its anterior and posterior divisions.

What muscles does the anterior division of the obturator nerve innervate?

The anterior division supplies muscles such as pectineus (partially), adductor longus, gracilis, and adductor brevis. It also provides an articular twig to the hip joint and a terminal twig to the femoral artery.

What muscles does the posterior division of the obturator nerve innervate?

The posterior division innervates obturator externus, adductor magnus (adductor part), and adductor brevis. Its terminal branch is a genicular branch to the knee joint.

What is the accessory obturator nerve?

Present in about 30% of individuals, the accessory obturator nerve arises from L3 and L4. It passes under pectineus to supply it, may give an articular twig to the hip joint, and can communicate with the anterior division of the obturator nerve.

What are some clinical conditions associated with the obturator nerve?

Clinically, the obturator nerve is involved in adductor spasm, often seen in spastic paraplegia and treatable with surgical division, and referred pain between the hip and knee joints due to shared innervation via L2–L4.

What is the role of the obturator nerve in joint innervation?

The obturator nerve provides articular branches to both the hip joint (via the anterior division) and the knee joint (via the posterior division's genicular branch), explaining why pain can refer between these joints.

Obturator Nerve (L2–L4) – Course, Divisions & Injury

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