Obturator nerve is the nerve that supplies muscles to thigh’s medial side and rises from lumbar plexus with root value ± and ventral segmentation belonging to L2 3 4. It travels deep into medial margin of psoas major and then goes further deep into external iliac vessels. The obturator nerve originates from the third and fourth lumbar nerves and is also at various juncture associated with L2. It is placed deep inside the obturator canal and as it leaves this canal it gets classified into posterior and anterior branches. The anterior branch of obturator nerve provides articular branch to hip along with anterior adductor muscles. It also provides to the lower medial thigh variable cutaneous branch. The deep abductor muscles are innervated by the posterior branch which also sends its articular branch up to the knee.
In pelvis the obturator nerve passes via medial border of psoas major and then goes behind iliac vessels so as to run laterally into the internal iliac vessels. Further it travels along side the pelvis lateral wall and gets attached to obturator internus along with the obturator vessels. Finally it reaches the obturator canal and gets divided into anterior and posterior branches.
In the anterior division of thigh, the obturator externus is placed above whereas the adductor brevis is located below. The posterior branch is placed in the back side of adductor brevis and comes down running vertically.
Mostly the obturator nerve damage occurs during surgery of pelvic or abdomen. Rarely though, this nerve at times gets trapped spontaneously at the point where it leaves pelvis. People suffering from obturator nerve injury complain of numbness and sparking pain coming out from thigh. Owing to this injury, the patient can suffer from adduction thigh weakness due to which he is unable to move both the thighs at the same time thereby resulting in instability in gait as well as posture. So as to confirm this injury electrical tests are conducted.
In case of nerve cut during surgery, the recovery can take around a year because the nerve regenerates very slowly (one inch every month). So as to encourage quick healing, physiotherapy is advised. Sometimes when the severity of injury or damage is unfathomable physiotherapy is advised for the first initial three months and if the nerve damage does not recover during this period surgical option is opted. In serious conditions, nerve transfer option is adopted in which the branch from neighboring femoral nerve from the groin is joined to obturator nerve. In case of obturator nerve entrapment or nerve blocks, steroid injections are prescribed for limited period. Even the obturator nerve decompression is performed at the point where it leaves the pelvis but this procedure does not warrant full success. In refractory cases, there is an indication of spinal cord stimulation.