Final Answer:
The type of synovial joint found at the base of the thumb (the trapeziometacarpal joint) is a saddle joint.
Step-by-step explanation:
The trapeziometacarpal joint, located at the base of the thumb, is a unique synovial joint with a saddle-shaped articulation. This joint involves the trapezium bone of the wrist and the first metacarpal bone of the thumb. The saddle joint allows for a wide range of movements, including flexion, extension, abduction, adduction, and opposition. The opposing surfaces of the trapezium and the first metacarpal create a highly mobile joint that is crucial for the intricate movements of the thumb. The saddle joint's design facilitates the thumb's ability to perform grasping and fine motor activities, contributing to the precision and dexterity of the human hand.