Bursitis is caused by inflammation of a bursa, a small fluid-filled sac that functions as a gliding surface to reduce friction between muscles, tendons, and joints during movement. There are 160 bursae located throughout the body. The major bursae are adjacent to the tendons near the large joints, such as the shoulders, elbows, hips, knees, and heels.
The bony point of the hip is called the greater trochanter. It is an attachment point for muscles that move the hip joint. The trochanter has a fairly large bursa overlying it that occasionally becomes irritated, resulting in hip bursitis (trochanteric bursitis). Bursitis can also result in pain in the groin area, when the iliopsoas bursa on the inside of the hip is irritated, but this is much less common. The main symptom of hip bursitis is pain at the point of the hip. The pain usually extends to the outside of the thigh area. In the early stages, the pain is usually described as sharp and intense. Later, it may feel achier and spread out.
Typically, the pain is worse at night, when lying on the affected hip, and when getting up from a chair after being seated for a while. It also may get worse with prolonged walking, stair climbing, or squatting.
The following risk factors have been associated with the development of hip bursitis:
- Repetitive stress (overuse) injury. This can occur when running, stair climbing, bicycling, or standing for long periods of time.
- Hip injury. An injury to the point of your hip can occur when you fall onto your hip, bump your hip on the edge of a table, or lie on one side of your body for an extended period of time.
- Spine disease. This includes scoliosis, arthritis of the lumbar (lower) spine, and other spine problems.
- Leg-length inequality. When one leg is shorter than the other by more than an inch or so, it affects the way you walk and can lead to irritation of a hip bursa.
- Rheumatoid arthritis. This makes the bursae more likely to become inflamed.
- Previous surgery. Surgery around the hip or prosthetic implants in the hip can irritate bursae and cause bursitis.
- Bone spurs or calcium deposits. These can develop within the tendons that attach to the trochanter. They can irritate the bursa and cause inflammation.
Sacroiliac joint dysfunction is often described as pain that is focused in the lower portion of the back and hip, although it may also radiate out to the buttocks and lower back. In some cases the pain may travel down the legs or around to the front, into the groin area. SI joint dysfunction may be caused by displacement of the SI joint or inflammation in the joint from trauma, chronic overuse, illness or infection.
The sacroiliac joint connects the sacrum (the lower part of the spine) and the pelvis (at the ilium). The bones are held together by strong ligaments that stabilize the joint allowing for little movement. The motion that does occur is a combination of sliding, tilting and rotation. The most the joint moves in sliding is only about a couple of millimeters, and may tilt and rotate two or three degrees.
SI joint dysfunction may result from injuries or disease processes. Traumatic injuries can result from car accidents, falls, or collisions during contact sports that lead to sprains or strains of the SI joint. Repetitive stress injuries can result from improper biomechanics that lead to abnormal alignment of the SI joint (such as when one leg is shorter than the other), or when engaging in activities that require repeated bending or twisting.
Piriformis Syndrome is an impingement syndrome that occurs when the piriformis muscle compresses the sciatic nerve. This causes pain in the buttocks region and may even result in referred pain in the lower back and thigh or leg. In addition to pain, weakness and even numbness or tingling may be felt in the same regions.
The piriformis muscle is a small muscle deep in the buttocks that rotates the leg outwards. It runs from the sacrum (the base of the spine) and attaches to the top of the femur (thigh bone). The sciatic nerve runs under this muscle and down the leg, although in about 10% of the population it actually runs through the muscle fibers.
Piriformis syndrome is predominantly caused by a shortening or tightening of the piriformis muscle. This can occur when the piriformis muscle is overloaded from activities such as exercising on hard surfaces or uneven ground, increasing exercise intensity too quickly, or sitting for long periods of time. Biomechanical inefficiencies can also lead to piriformis syndrome. This can include faulty foot and body mechanics, gait disturbances and poor posture or sitting habits.
