Synovial Joints

Plane (arthrodial) joints

These joints have a relatively flat articular surfaces that permit gliding movements in any plane. Some intercarpal joints, some intertarsal joints, and the acromioclavicular joint are examples of plane joints

Six Types of Synovial Joints

Plane/arthrodial joints. Hinge/ginglymus joints. Pivot/trochoid joints. Condyloid/ellipsoid joints. Saddle/sellar joints. Ball and socket/enarthrodial joints.

Synovial Joints

Have a joint space which may or may not be divided by interarticular discs or meniscus. A synovial membrane lining the joint cavity which produces synovial fluid for joint lubrication and nutrition. A fibrous joint capsule which may be reinforced by joint ligaments. A thin layer of articular cartilage, usually hyaline, without perichondrium covering the articular surfaces of the mating ones.

saddle (sellar) joints

In this joint, each articular sufrace has a concave and convex surface. The position of the convex and concave surfaces on one articular surface is reveresed on the opposing articular surface. This joint may permit biaxial or triaxial movement. The carpometacarpal joint of the thumb is a saddle joint. It permits biaxial movement in the saggital and frontal planes, but rotation is restricted by interlocking configuration of the opposing articular surfaces. The sternoclavicular joint is also a saddle joint. It allows triaxial movement because it has and interarticular disc that allows rotation.

Close Packed Position

The one geometric position in which opposing joint surfaces articulate perfectly. The joint is very stable in this position, and the joint capsule itself and ligaments are mostly tight. The joint is in the most efficient position for load bearing.

Loose Packed Position

The opposite of close packed position. In this position, the joint capsule is most slack and the ligaments are most lax. The joint is considered to be unlocked and inefficient for load bearing. Joint mobilization and distinguishing joint mobility are best assessed in the loose packed position.

condyloid (ellipsoid) joints

These joints have an oval concave articular surface and an opposing oval convex articular surface. They allow biaxial movement in sagittal and frontal planes. Rotation is restricted by the curvature of the opposing joint surfaces. The radiocarpal joint of the wrist, the metacarpophalangeal joints of the fingers, and the metatarsophalangeal joints of the foot are condyloid joints.

Ball and socket (enarthrodial) joints

These joints have one concave articular surface and one convex articular surface. The curvature of each articular surface is similar in all planes. These joints permit movement in all three planes (triaxial). the hip and glenohumeral joint are examples of ball and socket joints.

Hinge (ginglymus) Joints

These joints have one concave articular surface and one opposing convex articular surface. They allow mainly uniaxial movement in the saggital plane. The interphalangeal joints of the fingers and toes and the humeroulnar joint of the elbow are hinge joints.

pivot (trochoid) joints

These joints have one concave articular surface, one convex surface. They allow mainly uniaxial joint rotation in the transverse plane. The proximal radioulnar joint and the median alantoxial joints are classified as pivot joints.