In human anatomy, the trapezius is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula (shoulder blade).

The triceps brachii muscle (Latin for “three-headed arm muscle”) is the large muscle on the back of the upper limb of many vertebrates.

The Zygomaticus muscle is innervated by the facial nerve (the seventh cranial nerve). The Zygomaticus Major is a muscle of facial expression which draws the angle of the mouth superiorly and posteriorly (smile). However, the Zygomaticus Minor draws the upper lip backward, upward, and outward (used in making sad facial expressions).