What Is the Obturator Nerve?

Obturator nerve, one of the spinal nerves. It originates from the lumbar plexus and enters the small pelvis after exiting from the inner edge of the psoas major muscle. Pass the pelvis along the side wall of the small pelvis to the obturator canal and divide into two branches: the anterior branch between the long and short adductors; the posterior branch between the short adductor and adductor. The obturator nerve innervates the adductor muscle group and the obturator external muscle of the thigh, and is distributed on the skin on the inner side of the thigh. When this nerve is damaged, there is a movement and sensory disturbance in the area it governs.

Obturator nerve, one of the spinal nerves. It originates from the lumbar plexus and enters the small pelvis after exiting from the inner edge of the psoas major muscle. Pass the pelvis along the side wall of the small pelvis to the obturator canal and divide into two branches: the anterior branch between the long and short adductors; the posterior branch between the short adductor and the adductor. The obturator nerve innervates the adductor muscle group and the obturator external muscle of the thigh, and is distributed on the skin on the inner side of the thigh. When this nerve is damaged, there is a movement and sensory disturbance in the area it governs.

Chinese name

Obturator nerve

Foreign name

obturator nerve

From

From lumbar plexus

Perforation

With obturator artery

Dominate

Dominate the medial femoral muscle

Obturator nerve anatomy

Obturator nerve: It consists of the anterior thigh of the anterior branch of the 2nd to 4th lumbar nerves. After exiting the medial edge of the psoas major muscle, it enters the small pelvis. Go forward along the side wall of the small pelvis, pass through the obturator tube to the small pelvis to the femur, and divide it into two branches, anterior and posterior, and enter the adductor muscles of the thigh through the anterior and posterior short adductors, respectively. The muscle branches innervate the obturator external muscles and the thigh adductor muscles. The dermal branch is distributed on the skin on the inner side of the thigh. In addition, they branch out to the hip and knee joints.

Obturator nerve injury, weak thigh adduction, difficulty in crossing the lower limbs, thigh weakness and other symptoms; the symptoms are not significant. The obturator nerve is composed of the anterior branches of L2 to L4, which is oval at the beginning and flat in the pelvic cavity. It is divided into anterior and posterior branches through the obturator tube. The anterior branch follows the pubic branch and long adductor muscles, and the obturator external and short adductor muscles travel down and dominate it. The posterior branch is between the large adductor and the short adductor, and is dominated concurrently. In addition, the obturator nerve sends joints to innervate the hip and knee joints, so clinically, hip joint lesions are sometimes manifested as knee pain, or there is knee pain at the same time. This is a type of neurodiffusion pain, which is more common in children. Common, should be paid attention to clinically. Cerebral palsy patients often have hip adduction deformities, which are mainly caused by adductor muscle spasm. Femoral head necrosis patients often have adductor spasm and deep tenderness under the pubic branch. This may be caused by inflammation of the hip joint and obturator nerve hip branch during femoral head necrosis. Sometimes patients also show knee pain. If the obturator nerve is blocked or the nerve is blocked locally, the symptoms can be relieved. Massage the adductor muscles at the starting point can also reduce the symptoms. Simple adductor spasm or injury is rare, and generally manifests as adductor tenderness, aggravated pain when abducting the hip joint, and local massage or block anesthesia can relieve symptoms.

The branch of obturator nerve and its variation

The obturator nerve (lumbar 2-4) is a branch of the lumbar plexus, which exits from the medial edge of the psoas major muscle, descends into the pelvis, and reaches behind the common iliac artery. , Through the closed tube into the thigh, divided into two branches before and after. Anterior branch: the joint branch is sent to the hip joint; the other branch is to the obturator external muscle, long adductor and gracilis, and often branches to the pubis and short adductor. The terminal branch of the anterior branch is a cutaneous nerve that travels between the long adductor and gracilis muscle, and is distributed on the lower third of the skin of the medial thigh. Posterior branch: It passes through and dominates the obturator external muscle, and the secondary branches are distributed in a part of the large adductor muscle and the short adductor muscle. Nerves continue down to the knee joint, this branch often communicates with the saphenous nerve.

Variation: Some of the fibers of the obturator nerve do not enter the pelvis, but accompany the extrasacral blood vessels, pass through the deep surface of the inguinal ligament to the pubic muscle, and these fibers constitute the paraocclusal nerve. The prevalence in China is about 2.9%.

Obturator and obturator-related diseases

1. Obturator nerve block: Obturator nerve block is suitable for the treatment of hip and inner thigh pain, medial knee pain, femoral head ischemic necrosis, and differential diagnosis of hip pain.

Operation method:

Posture: The patient is supine with the thigh slightly abducted.

Puncture method; mark 1.3 ~ 2.0cm below the pubic tubercle, routine skin disinfection, use a 7mm 8cm long needle to insert the skin vertically into the inferior branch of the pubic bone, and the depth of the needle is 3.5 ~ 6.3cm. set. Withdraw the needle to the skin and adjust the direction of the needle so that the needle point is upward (head end) and outward, so that the needle body and the skin are at an angle of 80 °, and continue to insert the needle. Repeat this procedure, adjust the angle of the needle until you feel the needle slip into the closed hole, and then insert the needle 1 ~ 1.5cm, inject anti-inflammatory analgesic solution or 1% lidocaine, or 0.375% bupivacaine 8 ~ 10ml ( May contain 1: 1000 epinephrine), inject the medicine while withdrawing the needle.

Note: Do not insert the needle too deep, so as not to damage the bladder and other organs, withdraw before injection to avoid accidental entry into the blood vessels.

2. Obturator nerve injury:

The obturator nerve starts from the anterior thigh of the anterior branch of the lumbar 2-4 nerve, descends from the inner edge of the lumbar muscle through the outer wall of the true pelvis, passes through the internal iliac artery and the outer side of the ureter, passes through the obturator tube to the inner thigh. This nerve is divided into two branches in the anterior and posterior canal. The anterior branch enters the thigh above the obturator external muscle. The anterior branch is the pubis and long adductors, and the short adductor is behind. The branches innervate the hip joint, gracilis, long adductors, and short adductors, as well as two-thirds of the skin below and below the thighs. The posterior branch passes through the upper obturator external muscle and is located between the short adductor and the adductor. It branches to the obturator adductor, the adductor, and sometimes to the adductor, and has a joint branch to the knee joint.

Individual injuries are rare and can be caused by pelvic fractures, anterior hip dislocations, obturator hernias, pregnancy uterine compression, or dystocia. When the obturator nerve is injured, most of the adductor muscle function is lost, thigh adduction or external rotation is impaired, and the affected leg cannot actively rest on the healthy leg, and the sensory disturbance is not obvious. Because it has little effect on function, no special treatment is generally required.