Upper body muscles

Deltoids

This is the shoulder muscle and it lies to the front (anterior), side (middle) and rear (posterior) of each shoulder joint. It helps to provide protection and stability to the shoulder joint and move the arms in all directions.

Pectoralis major

This is the chest muscle. It helps to lift or raise the arm at the shoulder (shoulder flexion), and pull them across the chest (shoulder horizontal flexion). It also helps to pull down the arms at the sides (shoulder adduction).

Biceps

This is located on the front of the upper arm. It bends the arm at the elbow (elbow flexion). The biceps are helped out by two smaller muscles – the brachialis and brachioradialis.