The ischium is one of the three main bones that make up the pelvis, along with the ilium and pubis. It is located at the lower and back part of the pelvis and provides support when sitting. The ischium has a distinctive shape, resembling a curved bone, and features a bony prominence known as the ischial tuberosity, which bears weight when a person is seated. In addition to its structural role, the ischium serves as an attachment point for various muscles and ligaments. These include muscles involved in movement and stability of the hip joint. The ischium also contributes to the formation of the acetabulum, the socket that holds the head of the femur in the hip joint.