It cannot disappear altogether, only atrophy; which means that it is not being supported by nutrients or encouraged to grow under healthy activity.
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.
Skeletal muscle is associated with the upper arm.
The brachialis is a muscle in the upper arm that flexes the elbow joint.
What are the tendon in your arm?
no
Biceps or triceps
where you bored when you posted this question or have you pop you muscle in you left arm
Deltoid
which shoulder muscle allows you to adduct your arm
It depends. But, the triceps are 2/3 of your upper arm.
The posterior deltoid is one extensor of the upper arm.
The muscle in your arm contracts. The muscle on the other side of your arm, opposite from the side that you are flexing, stretches.