Origin: Nuchal ligament (or ligamentum nuchae) and the spinous processes of the vertebrae C7 through T3
Insertion: The upper borders of the 2nd through 5th ribs
Artery: Intercostal arteries
Nerve: 2nd through 5th intercostal nerves
Action: Elevate the ribs which aids in inspiration
The Serratus posterior superior (Serratus posticus superior) is a thin, quadrilateral muscle, situated at the upper and back part of the thorax. It arises by a thin and broad aponeurosis from the lower part of the ligamentum nuchae, from the spinous processes of the seventh cervical and upper two or three thoracic vertebrae and from the supraspinal ligament. Inclining downward and lateralward it becomes muscular, and is inserted, by four fleshy digitations, into the upper borders of the second, third, fourth, and fifth ribs, a little beyond their angles.