Joints
Hip joint
The opposite of the shoulder: a deep socket that encloses more than half the head, reinforced by the labrum and by the strongest ligaments in the body. Here stability wins over mobility, because in single leg stance the joint carries about three times body weight.
- Joint type
- Ball and socket joint with a deep socket (art. cotylica), three degrees of freedom
- Body region
- Hip
- Latin name
- Articulatio coxae
Movements, axes and normal values
| Movement | Plane | Axis | Normal range | End feel |
|---|---|---|---|---|
| Flexion | sagittal | transverse | 0-120 degrees with the knee bent, 0-90 with the knee straight | soft (soft tissue) |
| Extension | sagittal | transverse | 0-20 to 30 degrees | elastic |
| Abduction | frontal | sagittal | 0-45 degrees | elastic |
| Adduction | frontal | sagittal | 0-30 degrees | soft to elastic |
| External rotation | transverse | longitudinal through the femoral head | 0-45 degrees | elastic |
| Internal rotation | transverse | longitudinal through the femoral head | 0-45 degrees | elastic |
- Close-packed position
- Extension with internal rotation and abduction
- Resting (loose-packed) position
- 30 degrees of flexion, 30 degrees of abduction, slight external rotation
- Capsular pattern
- Internal rotation most limited, then flexion and abduction; extension relatively least limited
- Arthrokinematics
- A convex femoral head in a concave acetabulum: roll and glide run in opposite directions. During flexion the head rolls forward and glides backward. Without that posterior glide anterior impingement and groin pain follow.
- Stability
- The iliofemoral ligament (Y ligament of Bigelow, which limits extension and holds the upright human up with virtually no muscle activity), the pubofemoral ligament (limits abduction and external rotation) and the ischiofemoral ligament (limits internal rotation). The labrum deepens the socket and keeps the joint under negative pressure.
- Palpation
- Greater trochanter laterally, anterior superior iliac spine and ischial tuberosity as landmarks; the joint itself lies too deep to palpate directly.
- Clinical
- Hip osteoarthritis with the classic capsular pattern; femoroacetabular impingement (cam and pincer) in young athletes; labral injury; trochanteric bursitis and gluteal tendinopathy, which cause lateral pain without a joint restriction.
- Source
- Kapandji, Physiologie articulaire deel 2; Neumann, Kinesiology of the Musculoskeletal System; Magee, Orthopedic Physical Assessment