I think you are referring to the triceps. This is the muscle that attaches at the elbow and the shoulder. The one that you use when extending your arm. biceps; up triceps; under
Triceps brachii
The triceps
triceps brachii
triceps
There is not a single muscle that rotates the upper arm. The name of the muscle that contributes in rotation of the upper arm is deltoid muscle.
Biceps brachii muscle, is a muscle located on the inside of the upper arm Biceps femoris muscle, is one of the hamstring muscles at the back of each thigh
biceps brachii
Latissimus dorsi - this is the largest back muscle that runs from the lower back to the upper arm bone. It pulls the upper arm towards the body and acts as an internal rotator of the upper arm.
deltroid
Skeletal muscle is associated with the upper arm.
The triceps is the muscle at the back of your upper arm. It works to straighten your arm at the elbow.Yes, the tricep is located on the back of your arm in between your elbow and shoulder, closer to your shoulder though.
The biceps is the muscle on the front of the upper arm; it bulges when you bend your arm at the elbow. The triceps is the muscle on the back of the upper arm. Note that "biceps" and "triceps" can be either singular or plural. It is incorrect to say "bicep" or "tricep."
Triceps
The triceps are the the large muscle at the back of the upper arm.
The posterior deltoid is one extensor of the upper arm.
bicep is the muscle on the front upper arm used to bend arm. Tricep is on the back of the upper arm, used to straighten arm, so, I guess they could be considered partners.