Hip Anatomy

• Structures Of The Hip Joint
• Movements of the Hip

Bones

The hip joint connects the femur (thigh bone) to the pelvis. This type of joint is known as a ball-and-socket joint. The femoral head forms the ball, fitting into the acetabulum, a cup-shaped socket in the pelvis. This arrangement provides stability and allows for a wide range of movements.

Articular Cartilage

The femoral head and the acetabulum are covered with a layer of articular cartilage. Articular cartilage is a smooth, resilient tissue covering the hip joint's bony surfaces. It reduces friction and absorbs shock during movement, ensuring smooth articulation and protecting the joint from wear and tear.

Ligaments

The hip joint relies on a complex network of ligaments to maintain stability and regulate movement. These include the Iliofemoral, pubofemoral, and ischiofemoral ligaments. The ligaments of the hip joint form a sophisticated mechanism that preserves the hip joint's integrity and facilitates controlled motion.

Muscles & Tendons

The hip joint is surrounded by muscles and tendons that work together to facilitate movement, stability, and strength. The hip flexors enable hip flexion, lifting the leg forward and upward. The hip extensors facilitate moving the leg backward or straightening it from a flexed position. The hip abductors allow for moving the leg away from the body's midline. Meanwhile, the adductor muscles bring the leg back toward the midline in hip adduction. Additionally, the hip rotators, including deep external and internal rotators, allow for rotational movements of the hip joint.

Tendons are strong connective tissues and attach these muscles to the bones. They play a vital role in transmitting forces during movements, providing stability, and enabling essential actions like walking, running, and jumping.

Synovium

The synovium is a specialized tissue that lines the inner surface of the hip joint capsule. It plays a crucial role in the smooth functioning of the joint. The primary function of the synovium is to secrete synovial fluid, a clear and viscous lubricating fluid that fills the joint cavity.

Nerves & Arteries

The nerves of the hip transfer signals from the brain to the muscles that aid in hip movement. They also carry sensory signals such as touch, pain, and temperature back to the brain. The main nerves in the hip include the femoral nerve in the front of the femur and the sciatic nerve at the back. The hip is also supplied by a smaller nerve known as the obturator nerve.

In addition to these nerves, there are blood vessels that supply blood to the lower limbs. The femoral artery, one of the largest arteries in the body, begins deep in the pelvis and can be felt in front of the upper thigh.

As a ball-and-socket joint, the hip joint facilitates several types of movement: flexion, extension, abduction and adduction, and external and internal rotation.

Flexion

Flexion of the hip joint allows the thigh to move towards the chest. When the knee is flexed, the hip joint can be fully flexed with the thigh coming in contact with the abdomen.

Extension

Extension of the hip joint moves the thigh away from the trunk. It occurs when you extend your hip joint so that the angle between your thigh and pelvis increases.

Abduction & Adduction

Adduction and abduction of the hip joint are movements that involve pushing resistance towards or away from the body. Abduction refers to moving a limb away from the midline of the body, while adduction refers to moving a limb toward the midline.

Internal & External Rotation

Internal and external rotation of the hip joint is possible due to the unique shape of the bones and the surrounding structures that stabilize and support the joint. Internal rotation of the hip joint involves the rotation of the femur inward toward the midline of the body, while external rotation of the hip joint involves the femur rotating outward, away from the midline of the body. These rotations allow us to perform everyday activities like walking, as well as sports movements that require changes in direction.