Final answer:
The bone associated with the only saddle joint in the human body is part of the carpometacarpal joint of the thumb, between the trapezium and the first metacarpal bone.
Step-by-step explanation:
The bone that is associated with the only saddle joint in the human body is found in the carpometacarpal joint of the thumb. This joint is unique because it includes a biaxial saddle joint between the trapezium, which is a carpal bone, and the first metacarpal bone that forms the base of the thumb. The special structure of the saddle joint gives the thumb the capacity to move away from the hand along two different planes, making it opposable and allowing a wide range of movements including gripping and manipulation. Other types of joints like the hip or shoulder, which are ball-and-socket joints, allow for even greater ranges of motion but are not classified as saddle joints.