Ischial Bursitis

Excerpt

Ischial bursitis involves inflammation of the ischial bursa situated between the ischial tuberosity and the gluteus maximus muscle. The gluteus maximus covers the bursa during hip extension and in the standing position. However, the bursa and the ischial tuberosity are more directly engaged during flexion. When seated, the bursa is wedged between the bony surface of the ischial tuberosity and the external surface, making it prone to inflammation due to continuous weight-bearing pressure. Ischial bursitis is also known as ischio-gluteal bursitis or "weaver's or tailor's bottom" due to the historical association of the condition with professions, where workers sat on hard surfaces for much of the day.

The human body contains 2 types of bursae—constant and adventitial. Constant bursae develop in utero and are present from birth, while adventitial bursae form due to frictional stress and pressure between structures, often through myxoid degeneration of fibrous tissue. Some adventitial bursae develop due to pathologies, such as those occurring between preexisting structures and new bony growth. The ischial bursa develops from the frequent rubbing of the ischial tuberosity against the gluteus maximus during movement, making it an adventitial bursa. This bursa reduces friction between the 2 structures during hip flexion and extension, significantly aiding the lateral slide of the gluteus maximus and surrounding fatty tissue during hip flexion.