Biomech

7/9/99

Hip

• DJD
• Osteoarthritis
• More stabile compared to shoulder
• Angle of the joint—neck to shaft
• Coxa vara—angle <125°
• Normal—angle =125° +/-5°
• Coxa valga—angle >125° (valgus is lateral) (toe in)
• Antiversion angle—intersection of the long axis of the femoral head and the transverse axis of the femoral condyles-- 12°
• Angle develops
• At birth 40° back
• As we age goes to 15°

• ROM
• Forces
• Fig 7-12
• 100lb of body above hips, weight 150lbs
• force through R hip—50lbs
• 1/3 of body weight is in the legs
• gluteus medius balances
• 3x's the body weight in start of gait
• 9x's more force
• more force when the largest muscles are firing