Lecture Notes: The Hip Joint

Overview

• The hip joint is a large, strong synovial ball and socket joint.
• Connects the pelvis to the lower limb.

Structure

Femoral Head

• Forms approximately two-thirds of a sphere.
• Articulates with the acetabulum of the hip bone.
• Not entirely round; has a depression called the fovea for the ligament of the head of the femur.
• Covered entirely in articular cartilage, except for the fovea.

Acetabulum

• Bowl-like structure on the lateral aspect of the hip bone.
• Formed by the fusion of the ilium, ischium, and pubis.
• Acetabular notch is an incomplete inferior margin.
• Surrounded by acetabular labrum (lip) and transverse acetabular ligament.
• Contains acetabular fossa and lunate surface for femoral head articulation.

Joint Capsule

Fibrous Layer

• Attaches to acetabulum, transverse acetabular ligament, femoral neck.
• Contains spiral and circular fibers (orbicular zone).
  • Three intrinsic ligaments:
    • Iliofemoral Ligament: Strong, Y-shaped, prevents hyperextension.
    • Pubofemoral Ligament: Prevents over-abduction.
    • Ischiofemoral Ligament: Limits internal rotation.

Synovial Membrane

• Lines internal surfaces of fibrous layer and other non-articular surfaces.
• Covers femoral neck and area of acetabulum.
• Contains subsynovial retinacular arteries.
• Gives off the ligamentum teres for the artery to the femur head.

Movements

• Flexion: Iliopsoas, Sartorius, Rectus femoris, Pectineus.
• Extension: Gluteus maximus, Hamstrings (limited by iliofemoral ligament).
• Abduction: Gluteus minimus and medius, Tensor fasciae latae, Sartorius.
• Adduction: Adductor longus, brevis, magnus, Pectineus, Gracilis.
• Medial Rotation: Gluteus minimus and medius, Tensor fasciae latae.
• Lateral Rotation: Short lateral rotators, primarily Gluteus maximus.
• Circumduction: Combination of all movements.

Blood Supply

Arteries

• Medial Circumflex Femoral Artery: Supplies head and neck of femur, branches include transverse and ascending.
  • Cruciate and trochanteric anastomoses involvement.
• Lateral Circumflex Femoral Artery: Largest branch, supplies vastus lateralis, partakes in anastomoses.
• Retinacular Arteries: Supply femoral head and neck.
• Artery to the Head of the Femur: Branch of the obturator artery.

Nerve Supply

• Follows Hilton's law.
• Femoral Nerve: Innervates anterior aspect of the hip joint.
• Other Nerves: Sciatic, Obturator, Superior gluteal nerves.

Summary

• The hip joint is a complex, stable structure with a variety of movements.
• Supported by strong ligaments and a rich blood and nerve supply.
• Understanding these components is essential for clinical application.