The anatomy of the lower serratus anterior muscle: a fresh cadaver study.

Forty fresh cadaver dissections were studied to determine variations in the anatomy of the lower portion of the serratus anterior muscle. In all cases, the lower three to five slips of the serratus anterior muscle were supplied by one to three branches from the thoracodorsal artery, the so-called serratus branches. Three vascular patterns were identified: type I with one branch (40 percent), type II with two branches (50 percent), and type III with three branches (10 percent). The mean dimensions of the lower serratus anterior flap were 18.0 x 9.0 cm (range 12.0 x 8.0 cm to 21.0 x 15.0 cm). The mean pedicle length was 11.3 +/- 2.8 cm (range 7.3 to 13.3 cm). A crow's foot landmark has been identified to facilitate flap dissection. This landmark marks the juncture of the long thoracic nerve and the dominant serratus branch. This juncture can be found at the superior border of the sixth or seventh rib. The lower serratus anterior flap is ideal for reconstruction of small to moderate-sized defects because of its flat, broad dimensions and its long vascular pedicle.