The only saddle joint of the body is found in the ________________?

The saddle joint is a unique type of joint that allows for a range of motion, including flexion, extension, and some degree of rotation. The only saddle joint in the human body is located in the thumb at the carpometacarpal (CMC) joint, specifically between the trapezium bone of the wrist and the first metacarpal bone of the thumb. This structure allows for the thumb's distinctive ability to oppose, which means it can touch the other fingers—a crucial movement for grasping and manipulating objects.

In contrast, other joints mentioned, such as those found in the mandible, wrist, and hand, do not exhibit the same saddle joint characteristics. The mandible primarily utilizes hinge and gliding movements, while the wrist comprises several different types of joints, including condyloid and plane joints. The joints within the hand, aside from the thumb, also include metacarpophalangeal joints and interphalangeal joints, which are classified differently and do not have the same saddle shape. Thus, the thumb is the only anatomical structure that exemplifies a saddle joint in the human body.