Joints
Sternoclavicular joint
The only true bony connection between the arm and the axial skeleton. The disc turns two poorly matching surfaces into a functional ball and socket joint and absorbs the load arriving at the sternum from the arm.
- Joint type
- Saddle joint with a disc (art. sellaris), functionally three degrees of freedom
- Body region
- Shoulder
- Latin name
- Articulatio sternoclavicularis
Movements, axes and normal values
| Movement | Plane | Axis | Normal range | End feel |
|---|---|---|---|---|
| Elevation | frontal | sagittal | 0-45 degrees | elastic |
| Depression | frontal | sagittal | 0-10 degrees | hard |
| Protraction | transverse | vertical | 0-15 to 30 degrees | elastic |
| Retraction | transverse | vertical | 0-15 to 30 degrees | elastic |
| Axial rotation | along the long axis | longitudinal (clavicle) | 30-50 degrees, only during arm elevation | elastic |
- Close-packed position
- Maximal arm elevation
- Resting (loose-packed) position
- Arm resting by the side
- Capsular pattern
- Pain at the extremes of movement, especially on elevation
- Arthrokinematics
- The clavicular surface is convex craniocaudally and concave ventrodorsally. During elevation the clavicle rolls cranially and glides caudally; during protraction roll and glide both go forward.
- Stability
- Disc, anterior and posterior sternoclavicular ligaments, interclavicular ligament and the costoclavicular ligament, which ties the first rib to the clavicle and limits elevation.
- Palpation
- Right beside the jugular notch, medial to the head of the clavicle; have the patient shrug and you feel the head move.
- Clinical
- Dislocation is rare. A posterior dislocation is an emergency, because the trachea and great vessels lie directly behind it. Osteoarthritis causes a visible swelling that is easily mistaken for a subluxation.
- Source
- Kapandji, Physiologie articulaire deel 1; Neumann, Kinesiology of the Musculoskeletal System