Anatomy and biomechanics

Hip joint is a very stable joint by virtue of bony structures reinforced by cartilage and fibrocartilage. The static stability is obtained by joint capsule reinforced by accessory ligaments, whereas dynamic stability is obtained by various muscles around the hip which are attached from the lumbar spine and pelvic bone so it may affect over the pelvis and lumbar spine with reverse origin, and insertion and shortening of these muscles results in deformity of the pelvis and lumbar spine.