Hip Joint Lecture Notes

Introduction

• Topic: Hip Joint
• Type: Ball and socket joint
• Classification: Synovial joint
• Function: Connects axial skeleton to lower extremities; supports standing (static) and walking, running, weight-bearing (dynamic)

Anatomy of the Hip Joint

• Components:
  • Ball: Head of the femur
  • Socket: Acetabulum in the pelvic bone

Joint Capsule

• Characteristics: Strong, fibrous, but loose enough for a wide range of movements
• Attachments:
  • Acetabular labrum
  • Transverse acetabular ligament
  • Intertrochanteric line of the femur

Ligaments of the Hip Joint

• Outer Ligaments:
  • Iliofemoral Ligament: Y-shaped; prevents excessive lateral rotation and hyperextension; strongest ligament
  • Ischiofemoral Ligament: Prevents medial rotation and extension of the thigh
  • Pubofemoral Ligament: Limits abduction and extension of the thigh
• Inner Ligaments:
  • Transverse Acetabular Ligament: Converts acetabular notch into acetabular foramen; allows vessels and nerves passage
  • Ligament of the Head of the Femur: Pathway for foveolar artery; extra-synovial

Hip Joint Movements and Biomechanics

• No direct muscle attachments to femoral head, but many muscles cross the joint
• Movements:
  • Flexion: Psoas major, iliacus, sartorius, rectus femoris, pectineus
  • Extension: Gluteus maximus, hamstring muscles
  • Abduction and Internal Rotation: Gluteus medius, minimus, tensor fasciae latae
  • Adduction: Adductor longus, brevis, magnus, gracilis, pectineus
  • External Rotation: Obturator muscles, gemellus, quadratus femoris, gluteus maximus, piriformis

Range of Movements (Degrees)

• Flexion: 140°
• Extension: 15°
• Abduction: 40°
• Adduction: 25°
• Internal Rotation: 35°
• External Rotation: 45°

Blood Supply

• Major Arteries: Medial and lateral circumflex arteries (from femoral artery)
• Minor Arteries: Artery of the head of the femur
• Femoral Head Blood Supply:
  • Lateral epiphyseal branch of medial circumflex
  • Ascending branch of lateral circumflex
  • Ligamentum teres artery

Nerve Supply

• Main Nerve: Femoral nerve
• Others: Obturator nerve, sciatic nerve, nerve to quadratus femoris, superior gluteal nerve

Clinical Anatomy: Hip Dislocation

• Definition: Disruption of joint between femur and pelvis
• Symptoms: Pain, inability to move hip
• Complications: Avascular necrosis, nerve injury, arthritis
• Types:
  • Posterior Dislocation: Common; affects sciatic nerve
  • Anterior Dislocation: Rare; affects femoral nerve
• Causes: High-force trauma, motor vehicle accidents, falls, sports injuries
• Diagnosis: X-rays, CT scan to assess dislocation and fracture pattern