The serratus anterior free flap is based on blood supply from the serratus branch of the thoracodorsal artery and its corresponding venae comitantes. The long pedicle, freedom from the effects of peripheral vascular disease, and the ability to harvest multiple tissue types in various sizes as a single or chimeric flap make this a particularly versatile and useful flap. The knowledge of variants in branching patterns for the serratus and thoracodorsal system including distribution to individual slips of serratus muscle is necessary to safely and efficiently harvest this flap.