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