Expansion
Arises from the outer surface of the upper eight or nine ribs, supplied by the long thoracic nerve
Expansion
- Origin - outer surfaces of the upper eight or nine ribs
- Insertion - medial border of the scapula, on its costal surface
- Nerve - long thoracic nerve, roots C5, C6, C7
- Action - protracts and rotates the scapula, holding it against the chest wall
Because the nerve descends on the outer surface of the muscle in the mid-axillary line, it lies directly in the surgical field of an axillary node clearance and in the path of a lateral chest wall injury.
Denervation produces a winged scapula that becomes obvious when the patient pushes against a wall, the medial border lifts away from the thoracic cage.