ANATOMICAL VARIATION OF THE LATERAL THORACIC ARTERY: WHAT THE TEXTBOOKS AREN'T TELLING YOU

The lateral thoracic artery is the blood supply to the serratus anterior muscle and is typically described as arising directly from the second part of the axillary artery. Students expect to find this “normal” branching pattern, as variations are seldom mentioned. Variations are, however, relatively common, suggesting that they merit inclusion in regular anatomical instruction. Students at the Texas College of Osteopathic Medicine completed a standardized data sheet on the axillary artery branches during axillary dissection. All cadavers used in this study were acquired through the Willed Body Program at the University of North Texas Health Science Center (n=80; 20 males, 20 females). An observable lateral thoracic artery directly branching from the second part of the axillary artery was found in only 48% of the axillae observed. In 46% of axillae, an artery was observed traveling to the serratus anterior muscle branching from the thoracodorsal artery. In 25% of axillae, the lateral thoracic artery from the axillary artery was doubled by an artery branching from the thoracodorsal artery. In approximately half of all axillae, the lateral thoracic artery was observed to branch from the thoracodorsal artery rather than branching directly from the axillary artery, as “normally” expected. These results support previous work on variations of the lateral thoracic artery. Given the high frequency of anatomical variations, we also propose that information on variations ought to be incorporated into anatomical education.