Ischial bursitis is a common cause of posterior hip and buttocks pain. The ischial bursa lies between the gluteus maximus muscle and the ischial tuberosity (Fig. 121.1). The bursa serves to cushion and facilitate sliding of the musculotendinous unit of the gluteus maximus muscle over the bony ischial tuberosity. The bursa is subject to inflammation from a variety of causes with acute trauma to the buttocks and repetitive microtrauma being the most common. Acute injuries to the bursa can occur from direct trauma such as when falling on the ice onto the buttocks, from prolonged bicycle or horse riding, or being tackled when playing football or checked when playing ice hockey. Direct pressure forcing the ischial bursa against the ischial tuberosity from prolonged sitting on hard surfaces has also been implicated in the development of ischial bursitis. If the inflammation of the bursa is not treated and the condition becomes chronic, calcification of the bursa with further functional disability may occur. Gout and other crystal arthropathies may also precipitate acute ischial bursitis as may bacterial, tubercular, or fungal infections (Fig. 121.2).

The patient suffering from ischial bursitis, which is also known as weaver’s bottom (due to its prevalence in weavers that have to sit on the edge of their seat to operate their loom), most frequently presents with the complaint of severe pain with any pressure on the gluteus maximus muscle and ischial bursa (Fig. 121.3). Flexion of the spine to maintain a sitting position such as when riding a horse or sitting on a stool will exacerbate the pain. Physical examination of the patient suffering from ischial bursitis will reveal point tenderness over the ischial tuberosity (Fig. 121.4). The patient may also exhibit a positive hip extension test when the patient is asked to actively extend his or her hip against resistance while in the prone position (Fig. 121.5). If there is significant inflammation, rubor and color may be present and the entire area may feel boggy or edematous to palpation. Swelling, which at times can be quite dramatic, is often present. Passive flexion of the hip may exacerbate the pain of ischial bursitis. If calcification or gouty tophi of the bursa and surrounding tendons are present, the examiner may appreciate crepitus with active flexion of the trunk and/or hip, especially in the sitting position (see Fig. 121.2).

Plain radiographs are indicated in all patients who present with hip pain to rule out occult bony pathology (Fig. 121.6). Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging (MRI) or ultrasound imaging of the affected area may also help delineate the presence of other hip bursitis, calcific tendinitis, tendinopathy, triceps tendinitis, or other hip pathology. MRI or ultrasound imaging of the affected area may also help delineate the presence of calcific tendinitis or other hip pathology. Rarely, the inflamed bursa may become infected, and failure to diagnose and treat the acute infection can lead to dire consequences (Fig. 121.7).