Lip groove

The labial or trays groove ( Latin philtrum ) is a vertical depression in the skin between the base of the nasal septum and the upper lip in humans and other mammals .

External Images
	The face of a child with fetal alcohol syndrome

For humans and most primates (with the exception of wet-nosed ones ), the labial groove is a vestigial medial cavity between the nose and upper lip. It is in this place that the parts of the person’s face are connected during the development of his embryo in the second or third month of pregnancy. When this process occurs abnormally, a person has the so-called " cleft lip ". ^[1] A flattened (flattened) labial groove is one of the symptoms of fetal alcohol syndrome and Prader – Willi syndrome .

In most mammals, Filtrum is a narrow gap through which moisture, due to capillarity of the surface, enters , thereby keeping it moist. This helps determine the position of the sources of odors.

• 

  Filtrum in humans

• 

  Filtrum in a dog

Some cultures have legends and myths ^{[ what? ]} , telling about the appearance of this cavity in humans, in particular in the Jewish and Carpatho-Ruthenian. One of these legends says that when a child is born, a guardian angel descends to him and, putting his index finger on the baby’s lips, says, “Forget all your past lives so that they do not become a barrier to you in the new.” After that, the newborn has a dent under the nose from the tip of the finger of an angel.