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Title: Philtrum  
Author: World Heritage Encyclopedia
Language: English
Subject: Philtrum piercing, Cupid's bow, Upper lip, Williams syndrome, Toothbrush moustache
Collection: Dog Anatomy, Facial Features, Horse Anatomy, Lips, Mammal Anatomy, Primate Anatomy, Rodent Anatomy
Publisher: World Heritage Encyclopedia


Philtrum visible at centre
Dog philtrum
Precursor medial nasal prominence[1]
Anatomical terminology

The philtrum (Latin: philtrum, Greek: φίλτρον philtron), or medial cleft, is a vertical groove in the middle area of the upper lip, common to many mammals, extending from the nose to the upper lip. Together with a glandular rhinarium and slit-like nostrils, it is believed to constitute the primitive condition for mammals in general.[2]


  • Function 1
    • Development 1.1
    • Variation 1.2
  • Culture traditions about the philtrum 2
  • See also 3
  • References 4


In most mammals, the philtrum is a narrow groove that may carry moisture from the mouth to the rhinarium or nose pad through capillary action, to keep the nose wet. A wet nose pad is able to trap odor particles better than a dry one, thus it greatly enhances the function of the olfactory system.

For humans and most primates, the philtrum survives only as a vestigial medial depression between the nose and upper lip.[3]

The human philtrum, bordered by ridges, also is known as the infranasal depression, but has no apparent function. That may be because most higher primates rely more on vision than on smell, and so no longer need a wet nose pad or a philtrum to keep the nose pad wet. Strepsirrhine primates, such as lemurs, still retain the philtrum and the rhinarium, unlike monkeys and apes.[4]



In humans, the philtrum is formed where the nasomedial and maxillary processes meet during embryonic development (colloquially known as Hulse lines). When these processes fail to fuse fully in humans, a cleft lip (sometimes called a "hare lip") may result.

A flattened or smooth philtrum may be a symptom of fetal alcohol syndrome or Prader–Willi syndrome.[5]


A study of boys diagnosed with autism spectrum disorders found that a broader than average philtrum is one of a cluster of physical abnormalities associated with autism.[6]

Culture traditions about the philtrum

In Torah she has taught it.[7] Some believers of the myth speculate that this is the cause of the philtrum, but it does not have a basis in traditional Jewish texts.[8]

See also


  1. ^ hednk-032—Embryo Images at University of North Carolina
  3. ^ , University of Chicago Press, 1977, Vol. I, p. 16Living New World monkeys (Platyrrhini): with an introduction to PrimatesPhilip Hershkovitz,
  4. ^ Ankel-Simons, F. (2007). Primate Anatomy (3rd ed.). Academic Press. p. 394.  
  5. ^ FAS Clinical
  6. ^ Aldridge, Kristina; George, Ian D; Cole, Kimberly K; Austin, Jordan R; Takahashi, T Nicole; Duan, Ye; Miles, Judith H (2011). "Facial phenotypes in subgroups of prepubertal boys with autism spectrum disorders are correlated with clinical phenotypes". Molecular Autism 2 (1): 15.  
  7. ^ Gabriel's Palace: Jewish Mystical Tales, p57
  8. ^ Babylonian Talmud; Niddah 30b
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