To flex your thumb, bend it across your palm towards the base of your little finger, moving all joints of the thumb.
Essentially, thumb flexion involves bending your thumb inward, toward your palm. This action is crucial for grasping and manipulating objects. You are flexing your thumb when you:
- Make a fist (partially).
- Pinch something between your thumb and fingers.
- Hold a pen or utensil.
The movement involves multiple joints in the thumb, contributing to its overall flexibility and range of motion. The provided video excerpt describes flexing the thumb as bending the thumb across the palm so it touches the base of the little finger. This maximizes the flexion range of the thumb.
