What does a flexor do?

Flexors are muscles whose main action is to bend a joint. This can include bending a limb at the elbow, knee, or ankle, as well as bending, flexing, or rotating the fingers and toes. Flexor muscles are typically located on the front side of the body, in the opposing muscle pair to extensor muscles, which straighten a joint.

For example, the biceps brachii is a flexor muscle of the elbow joint. When you bend your elbow to put your hand to your mouth, your biceps brachii muscle contracts, pulling the forearm bone towards the upper arm bone.

The quadriceps femoris muscles are flexors of the knee, allowing you to bend your knee to sit or walk.

The gastrocnemius, or calf, muscle is a flexor of the foot, allowing you to rise up on your toes or walk.

Many other flexors are located in the hand, forearm, and foot for the precise control and movement of these areas.