The philtrum: anatomical observations from a new perspective

The anatomy of the upper lip has previously been studied with a focus on muscular components. The authors' group has recently demonstrated that the superficial fat of the face is partitioned into compartments by membranes and associated vessels. The authors implement this concept to evaluate the philtrum and gain a better understanding of upper lip anatomy, embryologic development, clefting, and surgical techniques.

Five fresh cadaver heads were used for gross anatomical dissection. Colored, latex-based paint was injected through the carotid arteries to define the arterial system. Dye was then injected subdermally into the philtral hollow, which was then dissected. Histologic specimens were stained with hematoxylin and eosin.

On gross dissection and histology, it was noted that dye did not stain the overlying skin or underlying orbicularis muscle. Furthermore, the dye did not progress laterally beyond the philtral columns. These lateral borders coincided with small ascending arteries and associated membranes branching off the superior labial artery, which the authors name the left and right ascending philtral arteries.

The vascular anatomy of the philtrum is directly related to compartmentalization of superficial fat of the upper lip. A consistent vascular arcade originating from the superior labial arteries includes the ascending philtral arteries and associated membranes that divide the philtral from the lateral lip compartments. These arteries coincide with the location of the philtral columns and clefting in the cleft lip. Understanding this anatomy of the lip will improve surgical techniques and give insight into mechanisms of development and clefting.