Muscle on upper chest that adducts upper arm?

The biggest and most visable is Pectoralis major; that is the "pecks" in slang terms.

There are two main ones, the tricep and the biscep. The tricep bicep is on the inside angle as defined by your elbow, the tricep is on the outside.

On the anterior: Biceps Brachii, Brachialis, Coracobrachialis. Posterior: The Triceps brachii mucle.

Those muscles are called the triceps.

Bisceps and triceps.