Musculus serratus anterior
Last edit by Alaric Steinmetz on
Synonyms: vordere Sägemuskel
The musculus serratus anterior is a skeletal muscle of the shoulder girdle.
Figure
Origin
The musculus serratus anterior usually originates with nine digitations from the 1st–9th ribs, or in some cases from the 1st–8th ribs.
Insertion
The insertion of the musculus serratus anterior extends from the superior angle to the inferior angle along the medial border of the scapula. Based on its insertion area, the muscle is divided into 3 parts:
Pars superior: This part inserts at or near the superior angle of the scapula.
Pars intermedia: This part inserts along the medial border of the scapula.
Pars inferior: This part inserts near or directly at the inferior angle of the scapula.
Function
All three parts of the musculus serratus anterior pull the scapula forward. This movement is a prerequisite for anteversion of the arm. In this function, the musculus serratus anterior acts antagonistically to the rhomboid muscles. The pars superior and pars inferior jointly serve to press the scapula against the thoracic cage. The rhomboid muscles act synergistically in this function. The pars inferior rotates the scapula outward and pulls the inferior angle outward and forward. This movement enables elevation of the arm above the horizontal plane. With the shoulder girdle fixed, all three parts can act as rib elevators and thus assist with respiration.
Innervation
The musculus serratus anterior is innervated by the Long thoracic nerve (C5-C7)[^1].
