Hip Anatomy

Pelvis

The pelvis is a basin-shaped structure that supports the spinal column and protects abdominal organs. It includes several parts, but the area most relevant to sports injuries is the hip socket, or acetabulum, where the head of your femur sits in.

Femur

This is your thigh bone, and it’s the longest bone in your body. The femur’s upper end is called the femoral head, which is shaped like a ball and fits into the acetabulum, forming the hip joint. This ball-and-socket structure allows a wide range of movement in different directions. It normally fits well and moves smoothly in the socket, but if it becomes misshapen such as in femoroacetabular impingement it can cause pain.

Articular Cartilage

This smooth, white tissue covers the surface of the ball and socket. It allows the bones to glide over each other with very little friction. It can get small focal injuries that can be treated arthroscopically, or if the damage is more diffuse such as in hip arthritis, may require a hip replacement.

Labrum

This is a ring of strong, flexible cartilage around the rim of the socket. It makes the hip socket deeper and adds stability to the joint. When it gets torn, it can cause a pain or pinching feeling deep in the groin.

Ligaments are like strong ropes that help connect bones and keep joints stable. The hip has several important ligaments:

Capsule

This is a strong band of tissue that circles the hip joint. It’s lined with a thin membrane called the synovium, which produces synovial fluid to lubricate the joint.

Ligamentum Teres

This small ligament connects the tip of the femoral head to the acetabulum. It also has a small artery within it that can supply a small amount of blood to the femoral head.

Several key muscles and their tendons provide movement and stability to the hip joint:

Gluteals

These are the muscles in your buttocks. They control hip movement in different directions and provide stability to the hip joint. In some cases, the gluteus medius and minimus can tear from their attachment on the femur, which may need to be repaired.

Hip Flexors

These muscles, including the psoas muscle, are in your lower belly. They help with lifting your knee and increasing the angle between your thigh and belly. In some cases they can become tight and get irritated.

Quadriceps

These are the strong muscles at the front of your thigh that allow you to straighten your leg from a bent position.

Hamstrings

These muscles at the back of your thigh help you to bend your knee. They start at the back of your pelvis in an area called the ischial tuberosity, sometimes called the sit bone. They can be injured and torn off their attachment there which may need surgical repair. The hamstring muscle itself can also be torn, which usually does not require surgery.

Each muscle has a tendon, a tough band of tissue that connects the muscle to your bone. Tendons help muscles move the bones.