Obturator Nerve Anatomy, Function & Diagram

Obturator Nerve: The obturator nerve begins at the average border of the psoas major muscle. It visits through the obturator foramen (an opportunity in the pelvic bone) before entering the thigh, where it branches into two parts, an anterior branch and a behind branch. The obturator nerve is part of the group of nerves called the introducing lumbar plexus.

It descends through the fibers of the psoas major, and materializes from its medial entrance near the brim of the pelvis; it then passes behind the universal iliac arteries, and on the oblique side of the constitutional iliac artery and vein, and runs along the lateral wall of the lesser pelvis, above and in façade of the obturator ocean liners, to the upper part of the obturator foramen.

Obturator Nerve Cadaver

The obturator nerve is mixed nerve that comes from from the lumbar plexus and innervates the tendons and skin in the medial region of the thigh.

The obturator nerve emerges from the ventral rami of the second, third and fourth lumbar nerves. The obturator nerve emerges from the between side of the psoas major, then it crosses the linea terminalis and passes by the lateral wall of the lesser pelvis. The obturator determination enters the obturator canal and divides into two incurable members the anterior and the posterior branch.

The anterior branch of the obturator nerve is larger than the backside, it runs between the adductor brevis and adductor longus tendons, then penetrates the fascia lata at the middle third of the medial surface of the thigh and continues as the cutaneous branch. The antecedent branch of the obturator nerve innervates the adductor brevis, adductor longus, pectineus and gracilis, also the skin at the medial part of the thigh as far as the knee joint.

The backside branch of the obturator nerve runs posterior to the adductor brevis. The posterior branch of the obturator nerve innervates the adductor magnus and extraneous obturator muscles, and the hip joint.

Obturator Nerve Block

Obturator nerve square is useful in the interpretation and administration of hip pain and spasm of the hip adductors thought to be subserved by the obturator nerve. The technique is also useful to provide surgical unconsciousness for the lower terminus when combined with lateral femoral cutaneous, femoral, and sciatic nerve block. Obturator nerve block with local anesthetic can be used as a diagnostic tool during differential neural restriction on an anatomic basis in the interpretation of hip pain.

If destruction of the obturator nerve is being scrutinized, this capacity is useful as a forebody indicator of the degree of motor and sensory impairment that the patient may experience. Obturator nerve block with local anesthetic may be used to palliate acute pain necessities, receiving postoperative pain relief, while waiting for pharmacologic plannings to become effective. Obturator nerve block with local anesthetic is also useful in the administration of hip adductor spasm, which may make perineal care or urinary catheterization difficult. This technique is also useful to aid in visceral therapy following hip incision.

Obturator nerve block with local opiate and steroid is also useful in the medication of stubborn hip pain when the pain is thought to be secondary to inflammation or entrapment of the obturator nerve. Massacre of the obturator nerve is occasionally pointed out for the palliation of persistent hip pain after upheaval to the hip that is mediated by the obturator nerve.

Obturator Nerve Innervation

Obturator nerve block is useful in the evaluation and management of hip pain and spasm of the hip adductors thought to be subserved by the obturator nerve. The technique is also useful to provide surgical anesthesia for the lower extremity when combined with lateral femoral cutaneous, femoral, and sciatic nerve block. Obturator nerve block with local anesthetic can be used as a diagnostic tool during differential neural blockade on an anatomic basis in the evaluation of hip pain.

If destruction of the obturator nerve is being considered, this technique is useful as a prognostic indicator of the degree of motor and sensory impairment that the patient may experience. Obturator nerve block with local anesthetic may be used to palliate acute pain emergencies, including postoperative pain relief, while waiting for pharmacologic methods to become effective. Obturator nerve block with local anesthetic is also useful in the management of hip adductor spasm, which may make perineal care or urinary catheterization difficult.

This technique is also useful to aid in physical therapy following hip surgery. Obturator nerve block with local anesthetic and steroid is also useful in the treatment of persistent hip pain when the pain is thought to be secondary to inflammation or entrapment of the obturator nerve. Destruction of the obturator nerve is occasionally indicated for the palliation of persistent hip pain after trauma to the hip that is mediated by the obturator nerve.

Obturator Nerve Entrapment

The obturator nerve arises from the lumbar plexus on the posterior abdominal wall and descends within the psoas muscle, emerging from the medial margin of the muscle to enter the pelvis. The nerve path continues by following along the lateral wall of the pelvis, passing through the obturator canal, to enter the medial compartment of the thigh. From 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.

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 physical therapy. More severe cases may require surgery.

Injury may be caused by:

• Nerve being stretched during surgery
• Entrapment within the obturator canal
• Compression during pregnancy
• Car or household accident
• Abdominal surgery.
• Athletes may present with pain that may be brought on by exercise, often sports involving a lot or running and twisting. They may have been predisposed to this injury by previous pelvic trauma or surgery.

Obturator Nerve Function

Obturator nerve block (ONB) is commonly performed to prevent sudden thigh adduction during transurethral resection of bladder tumor (TURBT), to provide optimal analgesia for knee surgery, to treat chronic hip pain, and to improve persistent hip adductor spasticity in patients with paraplegia, multiple sclerosis, or cerebral palsy. Labat first described an ONB technique based on surface landmarks in 1922. Since then, several ONB approaches using surface landmarks with or without nerve stimulation to localize the nerve have been reported. During the last decade, ultrasound-guided ONB techniques have gained immense popularity, as have other types of peripheral nerve block. In this review, we describe the anatomy of the obturator nerve, illustrate the ultrasound-guided ONB techniques reported thus far, and identify issues that need to be addressed in the future.

The obturator nerve arises from the anterior rami of the second, third, and fourth lumbar nerves. The nerve descends through psoas major and emerges from the medial border of this muscle. The obturator nerve then runs along the lateral wall of the lesser pelvis and extends to the anterior thigh after passing through the obturator canal. During its course, the obturator nerve divides into anterior and posterior branches. In a cadaveric study, bifurcation of these two main branches of the obturator nerve was determined to be intrapelvic (23.22%), within the obturator canal (51.78%), or in the medial thigh (25%).

The anterior and posterior branches of the obturator nerve, or the common obturator nerve, run between the pectineus and obturator externus muscles immediately after the nerve emerges from the obturator canal. Beyond this point, the two branches are usually separated by some of the fibers of the obturator externus muscle. The anterior obturator nerve branch initially passes through the interfascial plane between the pectineus and adductor brevis muscles. Further caudad, it runs between the adductor longus and adductor brevis muscles, innervating the adductor longus, adductor brevis, and gracilis muscles. The anterior branch rarely innervates the pectineus muscle. The posterior obturator nerve branch travels in the fascia between the adductor brevis and adductor magnus muscles. Throughout its course, the nerve usually supplies multiple branches to the adductor magnus and adductor brevis muscles and occasionally innervates the obturator externus and adductor longus muscles as well. The obturator nerve also provides articular branches for the hip and knee joints.

The articular branch supplying the hip joint is derived from the common obturator nerve or its branches at different levels in conjunction with the obturator. The posterior branch of the obturator nerve supplies terminal branches to the capsule of the knee joint in some individual . The typical cutaneous distribution of the obturator nerve is described in most textbooks to be the medial side of the thigh and above the medial side of the knee. However, the obturator nerve provides no cutaneous innervation in more than 50% of cases.