The joint that is an example of a ball-and-socket joint that allows for extension, horizontal flexion, abduction, and rotation is the shoulder joint. The shoulder is a highly mobile joint that permits a wide range of motion in multiple directions.
In contrast:
- The knee is primarily a hinge joint.
- The wrist is a complex joint allowing limited rotation and flexion/extension but is not a ball-and-socket.
- The elbow is also a hinge joint.
Therefore, the correct answer is Shoulder.