Serratus posterior superior muscle

The serratus posterior superior is a thin, quadrilateral muscle, situated at the upper and back part of the thorax, deep to the rhomboid muscles.

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.