According to the Spine Universe website, sciatica is a mild to severe pain in the back of the leg that is caused by compression or impingement of lumbar-spine or lower-back nerve roots or the sciatic nerve itself. Sciatica-related pain in the lower extremity follows the course of the sciatic nerve as it travels down the back of the thigh and into the calf. A number of conditions can cause sciatic pain in the hip.
Herniated Lumbar Disk
A herniated lumbar intervertebral disk is a common cause of sciatic pain in the hip. According to the Spine Health website, a herniated lumbar disk occurs when the disk's nucleus pulposus—the soft inner core—protrudes through the disk's fibrous outer ring and irritates a spinal nerve root, an offshoot of the spinal cord, where it leaves the spinal column. Herniations that compress or irritate one or more of the nerve roots that form the sciatic nerve cause sciatica symptoms. The Spine Health website notes that common mechanisms or causes of herniated lumbar disks include sudden, unguarded low-back twisting movements or traumatic injury, although most lumbar disk herniations occur from repetitive stress injuries. A herniated disk is also known by the following names: slipped disk, bulging disk, protruding disk or pinched nerve. Herniated lumbar disks often respond well to conservative care treatment methods, such as low back traction, joint manipulation, manual soft tissue therapies and certain rehabilitative exercises.
Lumbar Spinal Stenosis
Lumbar spinal stenosis can cause sciatic pain in the hip. The Family Doctor website states that the lumbar spinal canal—the space inside the lower spinal column that contains offshoots of the spinal cord—is very narrow and that bone and tissue around the canal grow over the span of many years, which can further narrow the canal. Narrowing of the lumbar spinal canal is called lumbar spinal stenosis, and compression or irritation of the nerves contained within can lead to sciatica symptoms, including back and leg pain. The Family Doctor website notes that lumbar stenosis can be caused by arthritis, falls, accidents, and wear and tear on the lumbar vertebrae and spinal joints. Sciatica due to lumbar spinal stenosis is more common in the elderly, and people with lumbar spinal stenosis possess a characteristic gait or walking pattern that involves a slight forward stoop and a wide stance.
Piriformis Syndrome
Piriformis syndrome can cause sciatic pain in the hip. According to the National Institute of Neurological Disorders and Stroke, or NINDS—a division of the National Institutes of Health—piriformis syndrome is a neuromuscular disorder that involves compression or irritation of the sciatic nerve by the piriformis muscle—a pear-shaped muscle in the gluteal region that runs between the sacrum and the top of the thigh. In most people, the sciatic nerve runs directly underneath the piriformis muscle, so if the muscle is tight or hypertonic, the sciatic nerve may be compressed and cause sciatica symptoms. In some people, however, the sciatic nerve actually pierces the piriformis muscle, running directly through its center. Because of the anatomical proximity of the sciatic nerve and the piriformis muscle, these individuals may be more likely to experience sciatica symptoms. NINDS notes that the prognosis for people with piriformis syndrome is good.
