Which muscle straightens a joint?

Answer 1

A muscle that straightens a joint is called an extensor.

Extensors are the muscles whose contraction extends or straightens a limb or other part of the body.
Extensor muscle

Answer 2

Flexor muscles will decrease the angle of the joint that they cross. Examples are biceps brachii (that bend your elbow) or the posterior thigh muscles, semitendinosus, semimembranosus and biceps femoris (also known as the hamstrings; that bend your knee).

Answer 3

The muscles that cause joints to straighten are called extensor muscles. These muscles include the muscles located at the knees and elbow that help to straighten these body parts. Flexor muscles help joints bend or contract joints.

Answer 4

Extension means straightening a joint.
Generally straightening a joint is to extend it.

For examples, if you hold you arm out straight, then bend it at the elbow, you have "flexed" the joint. Now when you return it to it's straight position, you have extended the joint.
The muscle is called the extensors. This is from a veterinary book so it is reliable Veterinary medical Terminology

Answer 5

An extensor is a muscle that straightens a joint. The opposite, a flexor, is a muscle that bends a joint.

Answer 6

Muscles that straighten the joints are extensors. Muscles the bend the joints are flexors.