The serratus anterior muscle is located along the sides of the ribs. It originates on the outer surface of the upper 8-9ribs, and inserts on the medial border of the scapula. This muscle acts on the scapula in several different ways. First it rotates the scapula to turn the glenoid fossa upward. It also protracted and elevates the scapula. And lastly it helps to prevent wining. This muscle is often shortened from prolonged sitting and work on a computer. Active trigger points in this muscle refer pain locally around the trigger point with spillover down the inside of the arm. Pain can also radiate into the inferior angle of the scapula.