Which of the following bones is located at the base of the thumb?

The bone located at the base of the thumb is the trapezium. This carpal bone is found in the wrist and plays a critical role in thumb movement and function, particularly at the carpometacarpal joint, where the thumb meets the wrist. The trapezium allows for a wide range of motion, making actions like grasping and pinching possible, which are essential for hand functionality.

In contrast, while the scaphoid also refers to a carpal bone located in the wrist, it is not directly involved at the base of the thumb but contributes to the overall structure of the wrist. Similarly, the trapezoid and hamate bones, while part of the carpal group, are situated more centrally or towards other fingers and do not play a significant role where the base of the thumb is concerned. Thus, the trapezium is specifically recognized for its unique position and function at the base of the thumb.