AN17.1-3 | Hip Joint — Glossary

A ball-and-socket synovial joint between the femoral head and acetabulum, designed for stability over mobility

The C-shaped articular surface of the acetabulum covered by hyaline cartilage that articulates with the femoral head

A fibrocartilaginous ring deepening the acetabulum by approximately 20%, increasing hip joint stability

The Y-ligament of Bigelow, the strongest ligament in the body, resisting hip extension and lateral rotation

An anteroinferior capsular ligament resisting excessive abduction and extension of the hip

A posterior capsular ligament resisting extension and medial rotation of the hip

An intracapsular ligament from the fovea capitis to the acetabular notch, carrying the foveal artery to the femoral head

Branches of the medial circumflex femoral artery running in synovial folds along the femoral neck, providing the principal blood supply to the femoral head

A branch of profunda femoris providing the principal blood supply to the femoral head via retinacular branches

Death of bone due to interrupted blood supply, commonly affecting the femoral head after intracapsular neck fractures

A fracture within the hip joint capsule that disrupts the retinacular blood supply, risking avascular necrosis of the femoral head

Surgical replacement of the femoral head only, preferred for displaced intracapsular fractures in the elderly

Replacement of both the femoral head/neck and acetabular socket, indicated for osteoarthritis, AVN, and rheumatoid arthritis

The most common type (90%), from dashboard injury, presenting with limb in flexion, adduction, and internal rotation

Less common (10%), from forced abduction and external rotation, presenting with limb in extension and external rotation

The tightening of hip ligaments in extension that stabilises the joint in standing without muscular effort

A nerve supplying a joint also supplies the muscles moving the joint and the skin over those muscles

The angle between the femoral neck and shaft, normally about 126 degrees

A reduced neck-shaft angle below 120 degrees, causing shortened limb and abductor weakness

An increased neck-shaft angle above 135 degrees, reducing the mechanical advantage of hip abductors

A fracture where the femoral head is driven medially through the acetabular floor into the pelvic cavity

A branch of the obturator artery travelling through the ligamentum teres to supply the femoral head, minor in adults