The biggest and most visable is Pectoralis major; that is the "pecks" in slang terms.
Trapezius Muscle!
trapezius
Triceps
triceps, coracobrachialis, and pecs
The brachialis is a muscle in the upper arm that flexes the elbow joint.
biceps & triceps?
Sternocleidomastoid
Pectoralis major
The biggest and most visable is Pectoralis major; that is the "pecks" in slang terms.
This is known as the bicep. The muscle that extends the lower arm is known as the tricep.
The subscapularis muscle medially rotates the scapula. The muscle is innervated by the upper and lower subscapular nerves.
If you cut through the middle of the muscle that flexes the upper wing on any animal, you render the wing useless. It will no longer flex, much like cutting a human Achilles heel.
The biceps muscle flexes and the triceps extends.
The teres major muscle rotates the upper arm medially, so the antagonists would be the external rotators: deltoid, infraspinatus, and teres minor.
the deltoid muscle is the muscle forming the rounded contour of the shoulder.the biceps brachii, or simply biceps in common parlance, is, as the name implies, a two-headed muscle located on the upper arm.The brachialis (brachialis anticus) is a muscle in the upper arm that flexes the elbow joint.The Coracobrachialis is the smallest of the three muscles that attach to the coracoid process of the scapula
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.