Pain felt on the side of the hip or the outer buttock often points directly to the gluteus medius muscle (GMed). This discomfort is frequently misdiagnosed as “sciatica” or “hip arthritis.” The GMed is a fan-shaped muscle that plays a significant role in maintaining stability throughout the lower body. Injury to this muscle or its tendon is a leading cause of chronic lateral hip pain.
Locating the Gluteus Medius and Its Function
The gluteus medius is a thick, broad muscle situated on the outer surface of the pelvis, mostly beneath the larger gluteus maximus. Its fibers originate on the outer surface of the ilium, the upper part of the hip bone. The muscle converges into a strong, flattened tendon that inserts onto the lateral surface of the greater trochanter, the prominent bony knob on the femur.
The muscle’s primary action is hip abduction, moving the leg away from the midline of the body. The gluteus medius is a major stabilizer of the pelvis, especially during walking or running. When standing on one leg, the GMed contracts powerfully to prevent the pelvis from dropping down on the opposite, unsupported side.
This stabilizing function is required constantly, making the muscle and its tendon susceptible to overuse or imbalance. The anterior fibers also assist with hip flexion and internal rotation, while the posterior fibers contribute to extension and external rotation. The health of the gluteus medius is closely linked to proper gait and balance.
Primary Cause: Gluteal Tendinopathy and Tears
The most frequent source of localized pain in this area is gluteal tendinopathy, an injury to the muscle’s tendon. This condition involves the breakdown or deterioration of tendon tissue resulting from a failed healing response to repeated stress. The term “tendinopathy” is preferred over “tendinitis” because the pathology is degenerative, meaning the rate of wear and micro-damage exceeds the body’s repair capacity.
A significant mechanism of injury is repetitive compressive loading of the tendon against the underlying greater trochanter bone. This compression is increased by certain postures, such as sitting with legs crossed, sleeping on the affected side, or standing with the body weight shifted onto one hip. Excessive tensile loads, where the tendon is stretched excessively, also contribute to tissue breakdown.
Underlying muscle weakness in the gluteus medius is a major factor, as it destabilizes the hip joint and places greater strain on the tendon during functional movements. Activities requiring significant muscle force, such as climbing stairs or running, can exacerbate the pain. The pain is felt directly over the greater trochanter and is often worse at night, particularly when lying on the side.
If degeneration is severe or a sudden, high load is applied, the condition can progress to a partial or full-thickness tear of the gluteus medius tendon. Full-thickness tears cause pronounced hip abductor weakness, leading to noticeable gait abnormalities, such as the pelvis dropping on the opposite side during standing. Gluteal tendinopathy is a component of Greater Trochanteric Pain Syndrome (GTPS).
Conditions Often Confused with Gluteus Medius Pain
A differential diagnosis is important because other conditions can mimic the discomfort originating from the gluteus medius tendon. One such condition is trochanteric bursitis, which involves inflammation of the bursa, a fluid-filled sac providing cushioning over the greater trochanter. Since the bursa lies between the bone and the GMed tendon, bursitis often co-occurs with or is secondary to gluteal tendinopathy.
Bursitis represents a distinct anatomical issue; the underlying pathology involves inflammation of the sac rather than tendon degeneration, though symptoms overlap. Pain from bursitis is also localized to the outer hip and aggravated by lying on the affected side. Historically, many cases of lateral hip pain were incorrectly attributed solely to bursitis.
Pain can also be referred to the lateral hip and buttock area from the lower back, known as lumbar radiculopathy. This occurs when a nerve root in the lumbar spine (L4, L5, or S1) is compressed or irritated, often by a herniated disc. Since the nerves supplying the gluteal region originate in the lower spine, irritation can project pain down the nerve pathway.
Referred pain from the spine, sometimes called sciatica, includes neurological symptoms such as tingling, numbness, or weakness that radiates down the leg. In contrast, GMed pain is localized to the muscle and tendon insertion and is acutely tender when pressed. Pain referred from the lumbar spine can sometimes cause “pseudotrochanteric bursitis,” complicating the diagnosis and emphasizing the need for thorough evaluation.