Saddle Joint
Saddle Joint: In a saddle joint (also called a sellar joint or articulation by reciprocal reception), the opposing surfaces are reciprocally concave-convex, allowing for motion in 2 planes. Motion is similar to how a horseback rider can move in a saddle. Examples include the trapeziometacarpal (TMC) joint of the thumb (1st carpometacarpal joint) and the sternoclavicular (SC) joint.
- Note: These joints allow movement primarily in two planes of motion , including flexion/extension and abduction/adduction of the thumb, and elevation/depression and protraction/retraction of the SC joint.
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Examples of Saddle Joints of the Human Body:
- Carpometacarpal joint of the thumb (CMC joint): This joint is located between the trapezium bone (carpal bone of the wrist) and the first metacarpal bone (1st long bone) of the thumb. It allows the thumb to perform opposition, which is the movement that enables the thumb to touch the tips of the other fingers, facilitating grasping and manipulating objects.
- Sternoclavicular joint: This is the joint between the sternum (breastbone) and the clavicle (collarbone). It is the only true bony attachment between the shoulder girdle and shoulder joint , and the upper body. It allows for elevation, depression, protraction, retraction, and some rotation, which is important for facilitating the motion of the scapula.
All Synovial Joint Types: