The ischium is a U-shaped bone that is the lowest of the three major bones that make up each side of the pelvis. The ischium is fused with the ilium and the pubis in the hip socket; its lower edge meets the pubis. The main anatomical features of the ischium are the ischial tuberosity (the broadening of the bone in the front part of the ischium) and the ischial spine. The ischium is attached to various muscles and, in humans and other primates, supports the weight of the body when sitting. The ischial tuberosity is the point of origin of the adductor and hamstring muscles of the thigh, as well as the sacrotuberus ligaments.

 

Male pelvis

 

Ischium tuberosity pain

Ischial tuberosity pain may be experienced by many different kinds of athletes, including soccer players, cyclists, baseball players, figure skaters, cheerleaders, and others whose activities involve a lot of jumping or running. It is often misdiagnosed as ischial bursitis, an extremely painful condition. Ischial tuberosity pain manifests as pain on the bottom of the buttock, especially when sitting and running. The area may also be tender and sensitive to touch.