Your hip joint is one of the largest and most stable joints in your body. A joint is a connection between two or more bones. Your hip is a ball and socket joint formed by the acetabulum of your pelvis-–the socket portion-–and the head of your femur (thigh bone), the ball part. This arrangement of your hip joint allows you to do certain degrees of movement of your lower limb in any direction.
Knowing your hip anatomy and its functions is important to better understand the conditions that affect your hip joint.
Bone Structures of the Hip
The bones comprising your hip joint are your femur and pelvis.
Your femur is the largest, heaviest and longest bone in your body. It has two bone ends: the head of the femur that connects with your pelvis forming the hip joint and the distal end – called the femoral condyles – that connects with your leg bones forming your knee joint.
The head of the femur, also called femoral head, is shaped like a sphere that fits almost perfectly on its corresponding socket formed by your pelvis.
- Pelvis (Pelvic bones)
You have two pelvic bones connected by the symphysis pubis in the front and the sacrum at the back. There are three bones comprising each of your pelvises: the ilium, ischium and pubis. These three bones fuse to form a deep depression called the acetabulum where your femoral head fits to form a joint.
Role of the Joint Cartilage
A joint cartilage is a smooth and slippery tissue covering bone ends of all your moving joints. Also called articular cartilage, joint cartilages allow smooth movements of your joints and prevent friction between the two bone ends.
As you age, this smooth joint cartilage may become damaged resulting from normal wear and tear of everyday use. Once damaged, your bone ends can rub against each other, causing osteoarthritis. The condition can cause pain, swelling and stiffness in your hip joint. Over time, constant rubbing of your bones can lead to permanent damage and cause disability.
Physical therapy can help with most cases of hip osteoarthritis. In some, hip replacement surgery may be necessary.
Supporting Structures of the Hip
The strength of your hip also depends on the supporting structures surrounding your joint. These surrounding hip joint structures contribute to the stability of the joint.
Your hip is supported by a capsule, ligaments and muscles.
Hip Joint Capsule
The hip joint capsule is a strong fibrous tissue that surrounds your hip joint. Along with the surrounding ligaments, the capsule provides added stability to your joint.
A ligament is a strong cord of tissue that connects a bone to another at a joint. The ligaments surrounding your hip joint work to keep your hip stable; limit certain hip movements; and prevent dislocation of your joint.
Your hip ligaments can become irritated, stretched or torn resulting in sprain. Hip ligament sprain can cause pain and swelling in your joint.
Your hip muscles are one of the strongest muscles of your body. This is especially true because of its functions of: maintaining stability in your hip joint, moving your lower limbs and keeping your posture.
More on the Hip Joint
Tortora, G. and Grabowski, S.: PRINCIPLES OF ANATOMY AND PHYSIOLOGY. 10th ed. John Wiley and Sons, Inc., 2003.
Seeley, R. et al: ESSENTIALS OF ANATOMY AND PHYSIOLOGY. 5th ed. McGraw – Hill, 2005.