Hip Anatomy

The hip joint is designed for both mobility and stability, allowing the entire lower extremity to move in three planes of motion. The hip provides an important shock absorption function to the torso and upper body as well as stability during standing and other weight-bearing activities.

Bones

The hip is actually a ball and socket joint, uniting tow separate bones, the femur (thigh bone) with the pelvis. The pelvis features tow cup-shaded depressions called the acetabulum, one on either side of the body. The femur is the longest bone in the body and connects to the pelvis at the hip joint. The head of the femur, shaped like a ball, fits tightly into the acetabulum, forming the ball and socket joint of the hip, allowing the leg to move forward and backward, side to side, and rotate right and left.

Cartilage

The acetabulum is lined with cartilage, which cushions the bones during weight-bearing activities and allows the joint to rotate smoothly and freely in all planes of movement with minimal friction.

Ligaments

The complex system of ligaments that connect the femur to the pelvis are essential for stability, keeping the hip from moving outside of its normal planes of movement.

Muscles

The muscles of the hip joint have dual responsibilities working synergistically to provide the power for the hip to move in all directions, as well as to stabilize the entire lower extremity during standing, walking, or other weight-bearing activities.