Deltoid
Flex and medially rotate arm; abduct arm; extend and laterally rotate arm.
Pectoralis major
Whole muscle adducts and medially rotates arm, clavicular head only flexes arm, and sternocostal head only extends arm.
Subscapularis
Medially rotates arm.
Serratus anterior
Abducts scapula and rotates it upward. This occurs when throwing a punch and is often called the boxers muscle.
Pectoralis minor
Abducts scapula and rotates it downward; elevates 3rd through 5th ribs during forced inspiration.
Rectus abdominis
Flexes vertebral column and compresses abdomen.
External oblique
Bilateral contraction flexes vertebral column and compresses abdomen. Unilateral contraction laterally flexes and rotates vertebral column to the opposite side.
Internal oblique
Bilateral contraction flexes vertebral column and compresses abdomen. Unilateral contraction laterally flexes and rotates vertebral column to the same side.
Transversus Abdominal
Compresses abdomen and stabilizes trunk.