Anatomy Lab: The Hip Joint

Introduction

• Focus on the hip joint structure and movements.
• Emphasis on hip flexion and muscles involved.
• Factors influencing hip flexion.

Structure of the Hip Joint

• Type: Ball and socket joint.
• Components:
  • Rounded head of the femur.
  • Cup-shaped socket of the pelvis (acetabulum).
• Function: Allows for a wide range of motion.

Movements of the Hip Joint

1. Flexion: Lifting the thigh towards the torso (knee towards chest).
2. Extension: Thigh moves back away from the torso (straightening leg from bent position).
3. Abduction: Moving the thigh away from the body's midline (spreading legs apart).
4. Adduction: Bringing the thigh back towards the body's midline (bringing legs together).
5. Internal Rotation: Rotating the thigh inward (toes towards each other).
6. External Rotation: Rotating the thigh outward (toes away from each other).
7. Circumduction: Combines all movements into a circular motion (drawing circle with knee).

Focus on Hip Flexion

• Primary Muscles Involved:
  • Iliacus
  • Psoas major and minor
• Function: Efficient force generation due to attachment from lower back and pelvis to thigh bone.

Helper Muscles

• Group A:
  • Anterior fibers of gluteus medius and minimus.
  • Tensor fasciae latae.
  • Sartorius.
  • Contribution: Flexion, internal rotation, abduction, stabilization.
• Group B:
  • Rectus femoris.
  • Pectineus.
  • Adductor longus.
  • Gracilis.
  • Contribution: Flexion, external rotation, adduction.

Complex Movement Patterns

• Group A's Role: Adds internal rotation and abduction to flexion (common in sports, dancing).
• Group B's Role: Adds external rotation and adduction.
• Factors Influencing Movement:
  • Muscle fibers may work selectively.
  • Individual differences like bone length, joint form, and strength.

Factors Influencing Hip Flexion

• Knee Position:
  • Straight knee limits flexion compared to a bent knee.
  • Bending the knee reduces muscle tension, increases range.
• Passive vs Active Flexion:
  • Passive flexion (using hands) is greater than active flexion.

Conclusion

• Understanding of muscles and movements enhances comprehension of complex patterns.
• Factors like knee position and individual biomechanics affect hip flexion.
• Preview of next episode on hip extension.

Prepare for next episode's focus on hip extension!