Hip Joint - Short Note

• Synovial, multiaxial ball-and-socket joint
• Articulation between the spherical head of the femur and the lunate surface of the acetabulum of the pelvic bone
• Designed for stability and weight-bearing at the expense of mobility

• Head of femur (covered by hyaline cartilage except at the fovea) fits into the acetabulum
• Rim is deepened by a fibrocartilaginous collar called the acetabular labrum
• Inferiorly, the labrum bridges the acetabular notch as the transverse acetabular ligament

• Iliofemoral (Y-shaped / "Y ligament of Bigelow") - anterior; strongest ligament in the body
• Pubofemoral - anteroinferior; limits abduction and extension
• Ischiofemoral - posterior; limits medial rotation and extension
• All three spiral around the joint and become taut in extension, aiding upright posture
• Intracapsular: Ligament of the head of femur (carries branch of obturator artery to femoral head)

• Medial and lateral circumflex femoral arteries (main supply)
• Branches of obturator, superior/inferior gluteal, and first perforating artery of profunda femoris

• Femoral, obturator, superior gluteal, and nerve to quadratus femoris (follows Hilton's law)

• Stability comes from: deep socket, strong capsule and ligaments, acetabular labrum, and surrounding muscles
• Vulnerable structures: sciatic nerve lies posteriorly (important in posterior dislocation)