Corpus: Serratus posterior superior muscle

The serratus posterior superior muscle is part of the deep layer of the secondary migratory back muscles. These muscles initially develop from the limb buds and later migrate into the back, and they are typically innervated by the anterior branch of the spinal nerves.

2.1. Origin

The serratus posterior superior muscle originates with a thin aponeurosis from the spinous processes of the two lowest cervical vertebrae (C6 and C7) and the two uppermost thoracic vertebrae (T1 and T2).

2.2. Appendix

The 3 to 4 descending muscle prongs of the serratus posterior superior muscle insert on the 2nd or 3rd to 5th ribs, lateral to the costal angle.

The serratus posterior superior muscle is innervated by the anterior branches of the spinal nerves, specifically from segments Th2 to Th5.

The serratus posterior superior muscle functions to lift the ribs, thereby supporting inspiration. This function is facilitated by the muscle's favorable leverage, due to its course relative to the axis of the costovertebral joints, allowing it to effectively assist in the process of inhalation.