The feature commonly referred to as a “nose dimple” is a minor, natural variation that contributes to facial individuality. Although the term suggests an indentation on the nose, it actually refers to a distinct anatomical structure situated just below the nose and above the upper lip. This feature is universally present in humans, but its depth and prominence vary significantly. Understanding this structure requires exploring its physical location, its formation during early development, and the genetic factors that determine its final appearance.
Anatomical Identity of the Feature
The vertical groove identified as a nose dimple is formally known as the philtrum, or the infranasal depression. It is bordered by two raised vertical ridges, called the philtral columns, which descend from the nasal septum to the central curve of the upper lip, known as the Cupid’s bow. The philtrum is a remnant of facial segment fusion during embryonic growth and serves no known functional purpose in humans.
The philtrum should be distinguished from other, less common nasal indentations. These subtle creases on the tip or bridge of the nose are variations in the underlying cartilage or bone structure. The philtrum, however, is a standard, central landmark of the upper lip area, defined by its characteristic groove and columns. The philtral columns are formed by the underlying orbicularis oris muscle, which controls lip movement.
The Genetic Basis of Formation
The philtrum’s formation results from intricate embryological development occurring early in the first trimester of pregnancy. Between the fourth and seventh week of gestation, the face develops from five primitive tissue masses, or facial prominences, that grow and fuse around the primitive mouth. The philtrum forms specifically at the junction where the two medial nasal processes merge with the maxillary processes on either side.
The shape and length of the philtrum are highly influenced by genetics. Facial morphology is significantly heritable, meaning genetic factors account for a large proportion of the variation seen in the population. Features like the philtrum are polygenic; their final appearance is determined not by a single gene, but by the cumulative effect of many genes. This complex interaction controls the growth and fusion of the facial prominences, dictating the depth and length of the philtral groove.
Variations in this fusion process lead to differences in philtrum presentation, ranging from a deep, defined groove to a flat, smooth appearance. Failure of the facial processes to fuse completely results in conditions like cleft lip, characterized by the absence of a properly formed philtrum. A flattened or smooth philtrum can also be a physical characteristic associated with certain genetic or developmental syndromes, such as Fetal Alcohol Spectrum Disorder.
Aesthetic Perception and Modification
The philtrum plays a significant role in facial aesthetics, contributing to the perceived proportions of the lower face and the shape of the lips. A well-defined philtrum with distinct columns is associated with a youthful appearance and a balanced facial structure. Conversely, the absence of clear philtral contours can make the upper lip appear longer vertically, which is sometimes perceived as an older feature.
Many individuals seek methods to modify the philtrum’s appearance, focusing on its length and definition. For permanent change, surgical procedures like the bullhorn lip lift are available to shorten the distance between the base of the nose and the upper lip border. This procedure involves removing a precise strip of skin under the nose, which shortens the visible length of the philtrum and enhances the upper lip’s prominence.
Non-surgical approaches are also used to alter the philtrum’s visual impact. Dermal fillers can be injected into the philtral columns to accentuate the ridges and deepen the central groove, creating a more defined appearance. Temporary cosmetic methods, such as strategic makeup contouring and highlighting, can also be employed to create an optical illusion of a shorter, more structured philtrum. Since the ideal philtrum length is subjective and varies across different groups, a customized approach to modification is important.