This chapter reviews the anatomy and biomechanics of the human thumb, examining the structural components and their functional role in movement. The thumb is composed of bones, ligaments, tendons, and dynamic muscles that enable the thumb to perform a variety of prehensile movements such as grasp, pinch, and precision manipulation. Central to the thumb’s unique capabilities is the trapeziometacarpal joint (TMC) a biconcavoconvex universal saddle joint that enables a wide range of motion such as flexion, extension, abduction, and opposition. This chapter will highlight the interplay between the soft tissues and the osteology to provide a wide range of motion while also providing stability. Additionally, a small review on the consequences of altered thumb kinematics can be found at the end.