Frontal branch of the superficial temporal artery: anatomical study and clinical implications regarding injectable treatments

BACKGROUND: The frontal branch of the superficial temporal artery (Fbr) is vulnerable to damage triggered by iatrogenic manipulation by both dermal filler and BoNT-A injection. The purpose of this study was to elucidate the branching pattern of Fbr and to determine its location and course on the lateral border of the frontal belly of the occipitofrontalis muscle (FB). METHODS: Sixty-four hemifaces from 38 Korean cadavers (26 males and 12 females; mean age 71.9 years) were dissected, and the location and course of the Fbr were identified with reference to the lateral border of the FB. RESULTS: The ramification of the frontal branch from the superficial temporal artery (STA) occurred 36.9 ± 14.24 mm (mean ± SD) superior and 17.2 ± 8.2 mm anterior to the posterior-most point of the tragus [i.e., tragion (Tg)]. The Fbr was observed as a single branch in 96.9% of cases and reached its destination at a single point in 71.9%. It reached the Fbr 14.8 ± 7.7 mm superior to the uppermost point of the eyebrow and 15.8 ± 9.1 mm from the lateral epicanthus. The Fbr bifurcated into superior and inferior branches before reaching the FB in 25.0% of cases. In two cases (3%), the Fbr ramified from the STA within 1 mm of the Tg. The diameter of the superior division of Fbr was 1.6 ± 0.5 mm at the lateral border of the FB and 1.8 ± 0.6 mm at other locations. CONCLUSION: Physicians performing injection treatments such as botulinum toxin type A and dermal filler injection to the posterior frontal area should be aware of the various distributions of the Fbr.ope