Acetabulum (morphology)

Acetabulum refers to the cup-shaped socket on the pelvis that serves as the articulation point for the femur (thigh bone), forming the hip joint. This structure is crucial for supporting the weight of the upper body during both static postures, like standing, and dynamic movements, such as walking or running. The acetabulum is a key component in the skeletal system, contributing to the mobility and stability of the hip joint.

Structure

The acetabulum is formed by the fusion of three bones of the pelvis: the ilium, ischium, and pubis, which meet at the acetabulum. The socket is oriented laterally, inferiorly, and anteriorly, providing a deep receptacle for the head of the femur. The depth of the acetabulum is further enhanced by a fibrocartilaginous rim called the labrum, which extends the surface area for articulation and aids in joint stability.

Function

The primary function of the acetabulum is to support the weight of the upper body while allowing a wide range of movements at the hip joint, including flexion, extension, abduction, adduction, and rotational movements. The shape and orientation of the acetabulum play a crucial role in determining the range of motion and stability of the hip joint. The labrum and surrounding ligaments add to the stability by preventing dislocation of the femoral head from the socket.

Clinical Significance

Injuries and diseases affecting the acetabulum can significantly impair mobility and quality of life. Common conditions include acetabular fractures, which often result from traumatic events like falls or motor vehicle accidents, and osteoarthritis, a degenerative joint disease that can wear down the cartilage lining the acetabulum, leading to pain and stiffness. Treatment options vary depending on the condition and its severity but may include physical therapy, pain management, and surgical interventions such as total hip replacement.

Development

The acetabulum develops from three separate ossification centers, one in each of the contributing pelvic bones. These centers fuse during adolescence, creating a single, continuous socket. The development and growth of the acetabulum are crucial for proper hip joint function and alignment. Abnormalities in the development of the acetabulum, such as in developmental dysplasia of the hip, can lead to joint instability and increased risk of osteoarthritis later in life.

See Also

• Hip joint
• Pelvic bone
• Femur
• Osteoarthritis
• Developmental dysplasia of the hip