The triceps are the largest muscle group in the arm. So, if you want big upper arms, concentrate on working your triceps rather than working your biceps.
.
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.
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.
The brachialis is a muscle in the upper arm that flexes the elbow joint.
What are the tendon in your arm?
no
The muscle that raises and rotates the arm is the deltoid muscle. It is a large, triangular muscle located in the shoulder that is responsible for various movements of the arm, including abduction (raising the arm) and rotation.
The posterior deltoid is one extensor of the upper arm.
Deltoid
where you bored when you posted this question or have you pop you muscle in you left arm
Biceps or triceps
which shoulder muscle allows you to adduct your arm