Upper limb

Serratus Anterior

Musculus serratus anterior

Origin

Outer surface of the first nine ribs, in a serrated pattern

Insertion

Medial border of the scapula, on the anterior (costal) surface

Function

Protracts the scapula and rotates it upward; holds the scapula against the thoracic wall

Innervation

Long thoracic nerve (C5-C7)

Movement & chain

Essential for pushing the arm forward (e.g. punching, pushing) and for raising the arm above shoulder height, where it works with the trapezius to upwardly rotate the scapula.

Palpation

Palpable in the axilla, along the lateral chest wall, well felt when the arm is pushed forward against resistance (e.g. against a wall).

Clinical

Loss of function of the long thoracic nerve produces a winged scapula, most visible when reaching forward or pushing against a wall.

Segmental innervation

Long thoracic nerve, C5-C7.

In clinical practice

An important focus point in scapular stability training (e.g. push-up plus) and in assessing scapular dyskinesis during physical examination.

Region in the model

Upper limb