Human Movement Science & Functional Anatomy of the:

Serratus Anterior

by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS


Serratus Anterior (Cadaver Dissection) -

What’s in a name


Attachments and Innervation:

Origin: Outer surfaces and superior borders of the upper eight or nine ribs (11, 22).

Insertion: Costal surface of the medial border of the scapula (11).

Nerve: Long thoracic nerve arising directly from the anterior rami of nerve roots of C5, C6, C7 and occasionally C8 (8, 11, 23).

  • The serratus anterior is a fan shaped muscle, which structurally may be divided into 3 sets of fibers. The first set of fibers (1st serration) insert into the superior angle of the scapula, originating on the first rib and occasionally the second (23). These fibers have a near horizontal fiber orientation, running parallel to the ribs they attach to. The second set of fibers ("2nd and 3rd serration") insert along the majority of the length of he medial border of the scapula, and course at a near 45º angle to the 2nd and 3rd rib. The third and largest set of fibers (the lower 5 or 6 serrations) insert into the inferior angle of the scapula and fan out to ribs 3 through 8 or 9. There is some evidence to suggest that the 1st set of fibers is innervated by C5, the second set C5 and C6, and the third by C6 and C7 (8); however, there