Obturator Nerve

Obturator nerve is a branch of the lumbar plexus that emerges from the medial border of the psoas muscle in the abdomen. The fibers of obturator nerve arise from ventral divisions of 2nd, 3rd and 4th lumbar nerves. The “obturator nerve” should not be confused with the “nerve to obturator internus”.

Course:

After emerging from the medial border of the psoas major muscle in the abdomen, the nerve accompanies the lumbosacral trunk down into the pelvis. There, passes behind the common iliac arteries and runs along the lateral wall of the false pelvis, in the angle between the internal and external iliac vessels. The nerve then reaches the obturator canal, which is the upper part of the obturator foramen devoid of obturator membrane. Here the nerve splits into anterior and posterior divisions, both of which pass through the canal and enter the adductor region of thigh through the adductor canal. In some subjects, the division of obturator nerve into anterior and posterior divisions takes place in the obturator canal.

Innervation:

In summary, the obturator nerve is responsible for the following:

  • Sensory innervation of the peritoneum of lateral pelvic walls
  • Sensory innervation of the skin of the medial aspect of thigh
  • Motor innervation of the adductor muscles of lower limb

Branches:

Anterior division of obturator nerve:

  • Course: It passes downward in front of the obturator externus and the adductor brevis and behind the pectineus and adductor longus muscles.
  • Muscular branches: To the following muscles;
    Gracilis
    Adductor brevis
    Adductor longus
    Pectineus (variable)
  • Articular branches: To hip joint
  • Sensory branches: To medial aspect of thigh

Posterior division of obturator nerve:

  • Course: It pierces the obturator externus and passes downward behind the adductor brevis and in front of the adductor magnus muscle.
  • Muscular branches: To the following muscles;
    Obturator externus
    Adductor part of adductor magnus
    Adductor brevis (variable)
  • Articular branch: To knee joint