A flexor is when a bone and a joint are attached by a flexible joint. It is a flexor if the center of the bones that are connected are brought closer when the muscle contracts. The movement that is being made is called a flexion.

A muscle is an extensor if the bones move away from each other when the muscle contracts.

The interaction of flexors and extensors.

Examples: Wrists: controls supination and pronation, Hamstring/ Quadriceps, controls straightening and bending your leg,

Bicep/ Triceps and controls bending your arm,Ankles and controls bending your foot,