To perform a thumb opposition, the thumb must do what?

To perform thumb opposition successfully, the key movement involves the thumb touching the fingertips of the same hand. This action allows the thumb to move across the palm, demonstrating its unique range of motion. Thumb opposition is crucial for grasping and manipulating objects, making it an essential function for activities requiring dexterity.

The movement involves the abduction of the thumb followed by flexion, allowing it to reach across the hand. This motion is not just about movement away from the hand or rotating around; it specifically requires the thumb to engage with the other fingers, highlighting the opposability that is a hallmark of human hand function. Therefore, touching the fingertips exemplifies the complete action of opposition, which is what distinguishes this movement from others.