Hip Joint: Anatomy & How It Works

Where is my hip joint?

Your hip joint is where your thigh bone meets your hip bone. You have two hip joints, one at the top of each of your thigh bones. Your thigh bones are the top part of your legs (above your knees, just below your waist, where the top of your pants sit). The part of your thigh bone that’s closest to your waist fits into your hip bone (pelvis).

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What does the hip joint look like?

Your hip joint is made up of your hip bone (pelvis) and your thigh bone (femur). Your femur is a long bone that has an angle near the top of the bone and points toward your pelvis. At the end of the thigh bone is the rounded end (femur head). This bone looks like a microphone in a stand.

The femur head rests inside a cup-like socket in your pelvis.

How big is my hip joint?

Your hip joint is one of the largest joints in your body. The top of your thigh bone (femur head) that fits into your hip bone (pelvis) is approximately 48 millimeters to 55 millimeters in diameter on the average person. This is about the same size as a small apple.

What is the hip joint made of?

There are several components that make up your hip joint:

• Bones: Your hip joint connects your thigh and hip bones.
• Cartilage: Cartilage is a smooth substance that covers the top of your thigh bone (femoral head) and the acetabulum socket. This substance is a cushion that absorbs impact when you walk and move.
• Synovium: The synovium is a thin cover that wraps around the bones in your joint. It makes a fluid that provides lubrication so your bones can move easily without resistance.
• Bursa: The bursa is a fluid-filled sac that provides cushioning and a smooth surface for the bones, muscles and tendons in your joints to move on.
• Ligaments: Ligaments are fibrous bands of tissue that connect bones to bones, specifically the femoral head to the acetabulum.
• Tendons: Tendons are fibrous bands of tissue that connect your muscles to your bones.
• Muscle: Your hips have large muscles that support your joint and help you move. Muscles in your hips include your gluteals, adductor muscles, iliopsoas muscle, quadriceps and hamstrings.