The pelvis is the sturdy ring of bones located at the base of the spine. It helps anchor the muscles and protect the organs in the lower abdomen. Each hip bone contains three bones—the ilium, ischium, and pubis—that are separate during childhood but fuse together as we grow older. These three bones meet to form the acetabulum—the hollow cup that serves as the socket for the ball-and-socket hip joint. Bands of strong connective tissues called ligaments join the pelvis to the sacrum, creating a bowl-like cavity below the rib cage. Major nerves, blood vessels, and portions of the bowel, bladder, and reproductive organs all pass through the pelvic ring. The pelvis protects these important structures from injury. It also serves as an anchor for the muscles of the hip, thigh, and abdomen.
Most pelvic fractures are caused by some type of traumatic, high-energy event, such as a car collision. Treatment for a pelvic fracture varies depending on the severity of the injury. While lower-energy fractures can often be managed with conservative care, treatment for high-energy pelvic fractures usually involves surgery to reconstruct the pelvis and restore stability so that patients can resume their daily activities.
Because the pelvis is a ring-like structure, a fracture in one part of the structure is often accompanied by a fracture or damage to ligaments at another point in the structure. Doctors have identified several common pelvic fracture patterns. The specific pattern of the fracture depends upon the direction in which it was broken and the amount of force that caused the injury. In addition to being described by the specific fracture pattern, pelvic fractures are often described as "stable" or "unstable," based on how much damage has occurred to the structural integrity of the pelvic ring.