1) Extensor muscle 2) Finger-straightening muscle 3) Limb muscle 4) Skeletal muscle 5) Striated muscle 1) Quad 2) Quadriceps 
adjective from the noun extension. The muscles which cause extension of a part are its extensor muscles; the surface of a part where those muscles are found is sometimes called the extensor surface.
• (n.) A muscle which serves to extend or straighten any part of the body, as an arm or a finger; -- opposed to flexor.
A muscle that is involved in straightening (extending) a limb or part of the body.
Adjective from the noun 'extension'. The muscles which cause extension of a part are its extensor muscles; the surface of a part where those muscles are found is sometimes called the extensor surface.
(ek-sten´sor) a muscle that straightens a joint.
Ex·ten'sor noun [ Latin , one who stretches. See Extend .] (Anat.) A muscle which serves to extend or straighten any part of the body, as an arm or a finger; -- opposed to flexor . 
To stretch out.
Muscle responsible for opening the angle of a joint
Type: Term Pronunciation: eks-ten′sŏr, -sōr Definitions: 1. A muscle the contraction of which causes movement at a joint with the consequence that the limb or body assumes a more straight line, or so that the distance between the parts proximal and distal to the joint is increased or extended; the antagonist of a flexor. See: muscle...(muscle) Type: Term Synonyms: extensor digitorum muscle
A muscle that, upon contraction, increases the angle of a joint.
An extensor is a muscle which serves to extend or straighten any part of the body, such as an arm or a finger.
extensor Any of various muscles that extend or straighten some part of the body; especially, a flexed arm or leg.
A muscle that pulls one bone away from another bone.
involving extensor surfaces of limbs. Contrast with flexor surfaces.
A muscle that straightens a limb
a muscle that serves to extend or straighten a part of the body.
Any muscle that can contract and create movement at a joint that increases the angle between the parts of a limb. Exs