Obturator Nerve

Original Editor - Jin Yoo

Top Contributors - Jin Yoo, Lucinda hampton, Leana Louw, Mariam Hashem and Kim Jackson

Introduction

1. femoral nerve. 2. obturator nerve. 3. saphenous nerve

The obturator nerve arises from the lumbar plexus and provides sensory and motor innervation to the thigh. The obturator nerve :

• Provides motor innervation to the medial compartment of the thigh
• Is essential to the adduction of the thigh.
• Provides sensory innervation to the medial upper thigh and provides articular branches to the hip and knee.
• The obturator nerve can become entrapped at the exit of the obturator canal or more distally by fascia, causing exercise-induced medial thigh pain, typically in athletes.

Anatomy

The obturator nerve arises from the lumbar plexus on the posterior abdominal wall. Root L2-L4

Hip adductors (and others)

Pelvis: The nerve descends medial to psoas major to the obturator canal where it divides into anterior and posterior divisions. The anterior division exits from the obturator canal to enter the medial compartment of the thigh. The posterior division exits through obturator externus.

Obturator nerve, anterior division marked

Medial compartment of thigh: Here the nerve divides into the anterior and posterior branch which are separated by the adductor brevis muscle.

• The posterior branch travels underneath the adductor muscle along the anterior surface of the adductor magnus muscle, innervating the obturator externus, adductor brevis, as well as part of the adductor magnus muscle that is attached to the linea aspera.
• On the anterior surface of the adductor brevis muscle the anterior branch travels underneath the pectineus and adductor longus muscles to innervate the adductor longus, gracilis, and adductor brevis muscles. This branch also often contribute to the pectineus muscle. The cutaneous branches innervate the skin on the medial thigh.

Function

The Anterior branch provides

• Motor innervation to the adductor brevis, adductor longus, gracilis, and in rare circumstances, the pectineus.
• In terms of cutaneous innervation, the anterior branch of the obturator nerve supplies the medial thigh, and just above the medial knee

The posterior branch of the obturator nerve

• Provides innervation to the adductor magnus, adductor brevis, and occasionally the adductor longus and obturator externus.
• Furthermore, the obturator nerve provides articular branches to the hip and knee joints.

Viewing

An under 5 minute video on the anatomy of the Obturator nerve

Physiotherapy

Hurdles, one of the sports that may cause obturator entrapment

Injury to the nerve is rare as it lies deep within the pelvis and medial thigh. It can be damaged through direct injury to the nerve or to surrounding muscle tissue. Mild damage to the obturator nerve can be treated with physiotherapy. More severe cases may require surgery.

Injury may be caused by:

• Nerve being stretched during surgery
• The nerve can become entrapped at the exit of the obturator canal or more distally by fascia. Entrapment of the obturator nerve causes exercise-induced medial thigh pain, typically in athletes. Athletes may present with pain that may be brought on by exercise, often sports involving a lot or running and twisting.Hip abduction and extension aggravate the pain, and resisted adduction does not elicit pain. Conservative treatment includes stretching and strengthening exercises, cognitive behavioral education, neural gliding, and manual therapy. Neurolysis or neurectomy may merit consideration if symptoms are refractory to treatment
• Compression during pregnancy
• Car or household accident
• Abdominal surgery

Obturator Neuropathy

Obturator canal highlighted red

Symptoms

• Pain & paresthesias may extend from hip to knee along the medial aspect of the thigh
• Extension or lateral leg movement can increase pain
• May have trouble walking or experience leg weakness due to problems adducting the ipsilateral hip

Signs

• Weak hip adductors on affected side
• Wasting of medial thigh
• Abnormal abduction of hip during ambulation resulting in a circumduction, wide-based gait
• Area of sensory loss or alteration in the mid and lower third of the medial thigh which sometimes may extend below the knee
• Ipsilateral loss of the hip adductor tendon reflex (test against asymptomatic leg as is not always present in healthy population)

Assessment

1. Needle EMG to confirm acute/chronic denervation of hip adductors excluding other lower extremity muscles such as iliopsoas or quadriceps
2. CT, MRI, or ultrasound imaging when intra-pelvic mass lesions are suspected of entrapping the nerve

Treatment

Tipton JS, 2008	Pharmacologic management of pain: NSAIDs Physiotherapy to improve strength and preserve mobility as well as ambulation Surgery considered if conservative treatments are non-effective
Sorenson EJ. Chen JJ. Daube JR. 2002	Patients with acute onset of obturator neuropathy had good recovery with conservative management Patients with chronic neuropathy have poorer outcome
Bradshaw C. McCrory P. Bell S. Brukner P. 1997	Good outcomes from surgical release Physiotherapy should be part of the rehabilitation plan Expected time for return to activity is 3 - 6 weeks

Copenhagen ex

Techniques

1. Copenhagen Adductor Exercise

A simple adductor strengthening exercise (Copenhagen Adductor Exercise ) with three progression levels, three times per week during the preseason (6-8 weeks), and once per week during the competitive season (28 weeks). For elaboration see Groin Strain

2. This 6 minute video is on Obturator Nerve Flossing