A ganglion is a sack of jelly-like fluid, sometimes called a cyst. They most commonly occur on the wrist, but may occur on the ankle or top of the foot. Wearing improperly fitting shoes can put stress on the foot and lead to ganglions. Bone spurs, repeated injury, inadequate warm-up prior to physical activity and poor muscle conditioning are also potential causes of ganglions. They are typically pea sized, but may become as large as a golf ball.

Ganglions may be mistaken for tumors, therefore a medical diagnosis is important. In addition to a physical examination, a podiatrist may use x-ray, fluid analysis, or an MRI to diagnose and determine the proper treatment for a ganglion.

Sometimes ganglions spontaneously disappear, only to reappear later. Surgery is typically necessary to remove a painful ganglion. Patients can usually walk within hours after surgery and are fully recovered in as little as three weeks.