Hip Anatomy and Function
The hip is one of the main weight-bearing joints in your body
The hip consists of two main parts:
- A ball (femoral head) at the top of your thigh bone (femur)
- A rounded socket (acetabulum) in your pelvis
Ligaments, which are bands of tissue, connect the ball to the socket and help keep the ball and socket steady. A smooth, tough material called articular cartilage, which cushions the bones and lets them move easily, covers the surfaces of the ball and socket.
All the rest of the surfaces of the hip joint are covered by a thin, smooth tissue liner called synovial membrane, which makes a small amount of fluid that acts as a lubricant so that the bones in the hip joint will not rub against each other.
What causes hip pain?
Pain in your hip can be debilitating, making it difficult for you to walk, climb stairs, or even pick up an object from the floor. It can limit your freedom of movement and ability to function independently.
While hip pain can be caused by deformity or by direct injury, like trauma or a sports injury, the most common cause of hip pain is osteoarthritis (OA) also known as degenerative joint disease (DJD). Depending on factors like age, weight, joint function, and activity, people with arthritis find their hip’s cartilage lining wears away over time. At that point, your bones begin to rub against each other, resulting in friction, swelling, pain, stiffness, and instability.
Experiencing joint pain day after day without relief can lead to “staying off” the joint -- which often weakens the muscles around it so it becomes even more difficult to move.