Serratus Anterior
The Serratus Anterior forms the lateral aspect of the upper torso musculature. It originates on the ribcage, attached to all but the lowest of the full ribs (numbers 1-9), and inserts at the medial anterior edge of the scapula. The tendon attachments on each rib, give the muscle an appearance similar to the edge of a serrated knife, which is where the name SERRATUS comes from. The “fingers” of the serratus anterior interlace with the “fingers” of the external oblique muscles and share fascial attachments on the ribs. Only a portion of the muscle can be seen. The pectoralis major lays over the upper portion of the SA, but the inferior four or five heads can be visible on lean people. Shown here, it looks like a row of bumps on the torso wall, just below the armpit. The actions of the serratus anterior are to pull the scapula away from the midline and to pull it closer into the ribs, hugging the body. It also functions to stabilize the scapula during contractions of the pectoralis major....