What Is A Extensor?

Answer 1

In general: any muscle that moves a limb away from your trunk/body or increases the angle in a joint. The opposite - muscles that pull your limbs back towards your body and/or decrease the angle in a joint - are generally called "flexors." Some of the trickier ones:

-Bending your back "backwards" is extension of the spine.
-Pushing your thigh backwards (as in, the opposite of pulling your knee up towards your chest) is extension.
-Kicking your leg out at the knee is extension (increases the angle between thigh and lower leg).
-Standing up on your toes is considered extension at the ankle, and also goes by another name - plantar flexion.

Answer 2

extensor is a muscle that is involved in extension. such as extensor carpi radialis