Synovial Joints

Synovial Joints permit…..

the most movement

_______ ________ lining the bony interfaces

articular cartilage

Synovial Joints defined by their…

joint capsule lined with a synovial membrane and filled with synovial fluid

Plane

• gliding movement

• ex: intercarpal joints

• they do facilitate translation

Hinge

• flexion/extension

• ex: humeroulnar joint

• has 1 rotational axis

Pivot

• axial rotation and pronation/supination

• ex: radioulnar

• has 1 rotational axis

Condyloid

• flexion/extension and abduction/adduction

• ex: MCPs 2-5 and facet joints

• has 2 rotational axes

• not circular

Saddle

• flexion/extension, abduction/adduction, and circumduction

• ex: first MCP (thumb), SC joint

• has 2 rotational axes

Ball and Socket

• flexion/extension, abduction/adduction, rotation, circumduction

• ex: gelnohumeral and femoroacetabular

• has 3 rotational axes

• circular

Floating

• variable actions permitted

• ex: scapulothoracic joint

• has 3 rotational axes

Joints with larger ROM are….

naturally unstable

The unstable joints require…

muscles to prevent dislocation (active stability)

Hip Joint

• higher passive support (stability)

• lower ROM (flexibility)

• deeper socket

• taut ligaments

Shoulder Joint

• low passive support (stability)

• higher ROM

• shallow socket

• loose ligaments

• need muscles to provide stability