The obturator nerve is the largest nerve in the anterior lumbar plexus. The lumbar plexus is a nerve network or grouping of nerves of the low back area. This series of nerves serves as a pathway for electrochemical signals connecting the brain to the back, abdomen, groin and knees. These nerves are considered part of the peripheral nervous system. The peripheral nervous system connects the body to the brain and spinal cord, also known as the central nervous system.
This nerve stems from the second through the fourth lumbar, or low back, nerves and runs into the anterior or front portion of hip area through the psoas major. The psoas major muscle, responsible for flexion of the hip, starts at the last thoracic or trunk spinal or vertebral bones, attaches to all the lumbar vertebral bones, and runs to the lesser trochanter of the femur. The lesser trochanter of the femur, also known as the long thigh bone, is a raised area on the top of the bone in the inner thigh where the muscle connects to the bone. The nerve then runs through the pelvis and thigh to supply sensory input to the front of the upper leg and knee area.
Problems and nerve damage of the obturator nerve can result from an injury to the nerve or to the surrounding musculature, causing an impingement or restriction. Pelvic injuries, including fractures, are a common factor in obturator nerve pain syndromes. Symptoms include pain in the groin which can radiate into the middle of the thigh down to the knee, and weakness or instability of the leg, especially with physical activities. Since nerve healing is a slow process, symptoms of nerve problems can last up to several months.
Utilizing methods to decrease inflammation around the obturator nerve may help ease pain. Inflammation is swelling, the body’s defense against further injury. NSAIDs, or non-steroidal anti-inflammatory drugs, often help control inflammation.
Conservative methods to treat problems with the obturator nerve include physical therapy for stretching to the area and a general exercise program, massage therapy to release muscle tightness and the use of modalities such as ultrasound and electrical stimulation for pain management. When symptoms of obturator nerve problems are severe, the injection of steroids may be necessary. This procedure is called an obturator nerve block. This technique is an effective means to ease inflammation and manage pain in most cases of nerve impingement or entrapment.