The Obturator nerve is a major peripheral nerve of the lower lumbar plexus and the nerve is formed by the spinal branches of L2-L4. The obturator nerve supplies the skin of the inner leg and muscles that provide inward motion (adduction) of the leg. The articular branches of the obturator and femoral nerves are responsible for most pain that occurs in the front and inner portion of the upper leg.
The obturator nerve is located just medial (midline) to the psoas and travels with this large muscle until it reaches the obturator foramen. Once the nerve is the obturator foramen it exits the pelvis and travels deep within the adductor muscles in a fascial sheet until it reaches and the back of the knee. These terminal branches of the obturator nerve innervates the posterior capsule of the knee joint.