THE HIP JOINT
The hip joint is a ball and socket joint and the shape and congruency between the femoral head and the acetabulum makes it a very stable, yet mobile joint.
The hip is a highly nociceptive (perception or sensation of pain) joint and range of motion at the hip joint can vary between individuals. Just like the pelvis, the hip joint shape and depth can also vary which in turn changes the orientation of the femoral head. Some people may appear more open and more prone to external/lateral rotation of the hip whilst others may appear deeper and more internal/medially rotated. This can be due to an individual’s natural shape, a lifetime of patterns that have changed the migration of the femur, congenital conditions such as EDS or through degenerative change such as in Osteoarthritis. We must always work within ranges that are comfortable for our client and never force ranges that may result in pain. The hip capsule itself is well supported via the soft tissue and strong ligamentous structures. The labrum provides extra support around the rim of the acetabulum and with good movement adequate synovial fluid will keep the cartilage healthy and strong and the hip can happily withstand the forces from the ground up. The cartilage of the hip does not respond well to shearing forces. Deep hip stability is critical for a healthy joint followed with a balance of strength and flexibility via the superficial muscle system is key to a happy hip joint!
Normal ranges of motion are:
| Flexion | 0 – 130 degrees |
| Extension | 0 – 30 degrees |
| Internal Rotation | 0 – 35 degrees |
| External rotation | 0 – 45 degrees |
| Abduction | 0 – 45 degrees |
| Adduction | 0 – 25 degrees |
Hip motion or femoral gliding will also occur with pelvic motion/rotation and are illustrated in the table below.
| Pelvic motion/rotation | Right hip motion | Left hip motion |
|---|---|---|
| Anterior tilt | Flexion | Flexion |
| Posterior tilt | Extension | Extension |
| Left lateral shift | Abduction | Adduction |
| Right lateral shift | Adduction | Abduction |
| Left transverse rotation | External rotation | Internal rotation |
| Right transverse rotation | Internal rotation | External rotation |
