Answer
Synovial joints have six-fold functional classification based on the kinds of movements of which they are possible;
1. Plane joints. Biaxial diarthrosis: These permit primarily back and forth movements. Examples are sternocostal joints
2. Hinge joints. Uniaxial diarthrosis: Permit movements like an hinge, that is angular opening and closing movements--flexion and extension
3. Pivot joints. Uniaxial diarthrosis--rotation. In this kind of joint the rounded surface of one bone articulates with the ring formed by the surface of another bone and a ligament. An example is the atlanto-axial joint--between the atlas and axis vertebrae.
4. Condyloid joints; Biaxial diarthrosis: In these joints the oval surface of one bone fits into the depression of another.
5. Saddle joint> . In this case articular surface of one bone fits into the saddle shaped depression of another. Example carpometacarpal joint between trapezium and metacarpal of thumb.
6. Ball and socket. In these the ball-like surface of one bone fits into the cup-like surface of another . The classical ball and socket joints are the hip joint and the shoulder joint
Work Step by Step
Examples of synovial joints:
1. Plane joints : Examples are joints between the manubrium of the sternum and the clavicle; sternocostal joints, ; intercarpal joints.
2. Hinge joints: Examples are elbow joints; ankle ; interphalangeal
3. Pivot joints: Example, Atlanto-axial joint. Pivot motion demonstrated by the nonverbal gesture when the head is moved side to side to signal "No."
4. Condyloid joints: Biaxial diarthrosis. These permit flexion and extension , abduction and adduction. Examples are the wrist joint ( carpo-metacarpal) and the metacarpo-phalangeal.
joints.
5.Saddle joint: These joints are capable of flexion, extension, limited circumduction, abduction and adduction. Examples are the carpometacarpal between the trapezium and the metacarpal. They permit flexion and extension , abduction and adduction.
6.. Ball and socket. Examples are the shoulder joint and the hip joints which are triaxial joints and are the most flexible in the body. The permit flexion and extension; abduction and adduction, and rotation.
