In the cat, the trapezius muscle is divided into three flat muscles that cover the upper back and the neck. The most anterior of these muscles is the clavotrapezius, named for its insertion into the clavicle.
The middle trapezius muscle is the acromiotrapezius, which covers the scapula and attaches to the acromion process of the scapula.
The most posterior of the three muscles is the spinotrapezius. It is triangular in shape and attaches to the spines of the thoracic vertebrae.