Trapezius (Part 3)

Origin = Spinous process of the seventh cervical and first three thoracic vertebrae.

Insertion = Spine of the scapula.

Action = Adduction (Retraction) of the scapula.

Trapezius (Part 4)

Origin = Spinous process of the fourth through twelfth thoracic vertebrae.

Insertion = Root of the scapula spine.

Action = Depression, adduction (retraction), and upward rotation of the scapula.