The subtle indent positioned centrally above the upper lip is a universally recognized human facial feature. This small vertical groove, present in almost everyone, often goes unnoticed despite its prominent location. Many people are curious about the name and origin of this distinct anatomical marking.
The Philtrum Defined
The indent above the lip is known as the philtrum. It is a vertical groove located in the midline of the upper lip, extending from the base of the nose to the vermilion border. It is bordered by two raised ridges, often called philtral columns, descending towards the central portion of the Cupid’s bow. The term “philtrum” originates from the Ancient Greek word “philtron,” meaning “love charm” or “a mark to kiss,” reflecting an older cultural association.
How the Philtrum Forms
The philtrum’s formation occurs early in fetal development, during the sixth and seventh weeks. During this period, several facial structures grow and fuse to create the upper lip and philtrum. Specifically, the medial nasal prominences, forming the central part of the nose, and the maxillary prominences, contributing to the upper jaw and sides of the upper lip, merge. The philtrum is a direct result of the successful fusion of these prominences in the midline. This fusion process is a developmental milestone, indicating the proper formation of the mid-facial region.
Variations and Medical Significance
The appearance of the philtrum can vary significantly among individuals, displaying differences in length, width, and depth. Some people have a deep and well-defined philtrum with prominent ridges, while others may have a shallower or smoother appearance. These variations are often genetically determined and represent a range of typical human facial diversity.
The philtrum also holds medical significance as an indicator of proper facial development. Its absence or an unusual formation can signal underlying developmental issues. For instance, an incomplete fusion of facial prominences during embryonic development can lead to conditions such as a cleft lip, where the philtrum is imperfectly formed or entirely absent. A smooth or flattened philtrum is also a characteristic feature associated with Fetal Alcohol Syndrome (FAS), a condition resulting from prenatal alcohol exposure. In these cases, the philtrum’s altered appearance can serve as a diagnostic marker.