Anatomy and Variations of the Lip

  • Koichi Watanabe
  • Tsuyoshi Saga


The lips are two flaps surrounding the oral orifice. As they are located at the entrance to the digestive tract, the external surface is covered with skin and the internal surface with mucosa. Externally, the appearance of the lip can vary because of syndromes affecting the face. Lip shape is usually defined by the shape of the philtrum. The lateral border of the lip and the nasolabial fold differ among individuals in shape and length. Internally, the labial salivary glands can be affected by disease and aging. The muscles in the lips can also be altered by certain diseases. In this chapter, we describe the anatomy and variations of the lip.


  1. Berman P, Desjardins C, Fraser FC (1975) The inheritance of the Aarskog facial-digital-genital syndrome. J Pediatr 86:885–891CrossRefGoogle Scholar
  2. Caksen H, Odabas D, Tuncer O (2004) A review of 35 cases of asymmetric crying facies. Genet Couns 15:159–165PubMedGoogle Scholar
  3. Chandler KE, Kidd A, Al-Gazali L et al (2003) Diagnostic criteria, clinical characteristics, and natural history of Cohen syndrome. J Med Genet 40:233–241CrossRefGoogle Scholar
  4. Chi AC, Lambert PR, Richardson MS et al (2011) Oral mucoceles: a clinicopathologic review of 1,824 cases, including unusual variants. J Oral Maxillofac Surg 69:1086–1093CrossRefGoogle Scholar
  5. Daniels JSM (2010) Congenital double upper lip: a case report and review of the literature. Saudi Dent J 22:101–106CrossRefGoogle Scholar
  6. Drummond JR, Chisholm DM (1984) A qualitative and quantitative study of the ageing human labial salivary glands. Arch Oral Biol 29:151–155CrossRefGoogle Scholar
  7. Ethunandan MG (2016) Chapter 9: Oral cavity. In: Brennan PA, Mahadevan V, Evans BT (eds) Clinical head and neck anatomy for surgeons. CRC Press, Boca Raton, pp 77–80Google Scholar
  8. Fara M (1990) Chapter 51. The musculature of cleft lip and palate. In: JG MC (ed) Plastic surgery general principles, vol 1. WB Saunders Co, Philadelphia, pp 2598–2612Google Scholar
  9. Gleeson M (2016) Chapter 31. Oral cavity. In: Standring S (ed) Gray’s anatomy, 41st edn. Elsevier, Amsterdam, pp 507–508Google Scholar
  10. Gupta R, Prasad P (2009) Congenital hypoplasia of depressor angularis oris muscle. Med J Armed Forces India 65:188–189CrossRefGoogle Scholar
  11. Hood RL, Lines MA, Nikkel SM et al (2012) Mutations in SRCAP, encoding SNF2-related CREBBP activator protein, cause Floating-Harbor syndrome. Am J Hum Genet 90:308–313CrossRefGoogle Scholar
  12. Horn D, Majewski F, Hildebrandt B et al (1995) Pallister-Killian syndrome: normal karyotype in prenatal chorionic villi, in postnatal lymphocytes, and in slowly growing epidermal cells, but mosaic tetrasomy 12p in skin fibroblasts. J Med Genet 32:68–71CrossRefGoogle Scholar
  13. Iwanaga J, Watanabe K, Schmidt CK et al (2017a) Anatomical study and comprehensive review of the incisivus labii superioris muscle: application to lip and cosmetic surgery. Cureus 15:e1689Google Scholar
  14. Iwanaga J, He P, Watanabe K et al (2017b) Intraoral observation of the mentalis and incisivus labii inferioris muscles. J Craniofac Surg 28:2159–2161CrossRefGoogle Scholar
  15. Kassan SS, Moutsopoulos HM (2004) Clinical manifestations and early diagnosis of Sjögren syndrome. Arch Intern Med 164:1275–1284CrossRefGoogle Scholar
  16. Koh KS, Kim DY, Oh TS (2016) Clinical features and management of a median cleft lip. Arch Plast Surg 43:242–247CrossRefGoogle Scholar
  17. Lin DS, Huang FY, Lin SP (1997) Frequency of associated anomalies in congenital hypoplasia of depressor anguli oris muscle: a study of 50 patients. Am J Med Genet 71:215–218CrossRefGoogle Scholar
  18. Majewski F, Ranke M, Kemperdick H, Schmidt E (1981) The Weaver syndrome: a rare type of primordial overgrowth. Eur J Pediatr 137:277–282CrossRefGoogle Scholar
  19. Martins WD, Westphalen FH, Sandrin R et al (2004) Congenital maxillary double lip: review of the literature and report of a case. J Can Dent Assoc 70:466–468PubMedGoogle Scholar
  20. Meinecke P, Schaefer E, Engelbrecht R (1983) The Weaver syndrome in a girl. Eur J Pediatr 141:58–59CrossRefGoogle Scholar
  21. Momeni P, Glöckner G, Schmidt O et al (2000) Mutations in a new gene, encoding a zinc-finger protein, cause tricho-rhino-phalangeal syndrome type I. Nat Genet 24:71–74CrossRefGoogle Scholar
  22. Pessa JE, Zadoo VP, Adrian EK Jr et al (1998) Variability of the midfacial muscles: analysis of 50 hemifacial cadaver dissections. Plast Reconstr Surg 102:1888–1893CrossRefGoogle Scholar
  23. Rodríguez-Vázquez M, Carrascosa-Romero MC et al (2007) Congenital gingival hyperplasia in a neonate with foetal valproate syndrome. Neuropediatrics 38:251–252CrossRefGoogle Scholar
  24. Rogers GF, Mulliken JB (2007) Repair of transverse facial cleft in hemifacial microsomia: long-term anthropometric evaluation of commissural symmetry. Plast Reconstr Surg 120:728–737CrossRefGoogle Scholar
  25. Rubin LR, Mishriki Y, Lee G (1989) Anatomy of the nasolabial fold: the keystone of the smiling mechanism. Plast Reconstr Surg 83:1–8CrossRefGoogle Scholar
  26. Schinzel A (1991) Tetrasomy 12p (Pallister-Killian syndrome). J Med Genet 28:122CrossRefGoogle Scholar
  27. Schwartz CE, Gillessen-Kaesbach G, May M et al (2000) Two novel mutations confirm FGD1 is responsible for the Aarskog syndrome. Eur J Hum Genet 8:869CrossRefGoogle Scholar
  28. Scott J (1980) Qualitative and quantitative observations on the histology of human labial salivary glands obtained post mortem. J Biol Buccale 8:187–200PubMedGoogle Scholar
  29. Sokol RJ, Delaney-Black V, Nordstrom B (2003) Fetal alcohol spectrum disorder. JAMA 290:2996–2999CrossRefGoogle Scholar
  30. Stretch JR, Poole MD (1990) Nasolacrimal abnormalities in oblique facial clefts. Br J Plast Surg 43:463–467CrossRefGoogle Scholar
  31. Sumi M, Yamada T, Takagi Y, Nakamura T (2007) MR imaging of labial glands. AJNR Am J Neuroradiol 28:1552–1556CrossRefGoogle Scholar
  32. Tessier P (1976) Anatomical classification of facial, cranio-facial and latero-facial clefts. J Maxillofac Surg 4:69–92CrossRefGoogle Scholar
  33. William R (2015) Chapter 2.13. Abnormalities of the Philtrum. In: The bedside dysmorphologist. Oxford University Press, Oxford, pp 48–51Google Scholar
  34. Wilson DI, Burn J, Scambler P et al (1993) DiGeorge syndrome: part of CATCH 22. J Med Genet 30:852–856CrossRefGoogle Scholar
  35. Zufferey J (1992) Anatomic variations of the nasolabial fold. Plast Reconstr Surg 89:225–231CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Koichi Watanabe
    • 1
  • Tsuyoshi Saga
    • 1
  1. 1.Kurume University School of MedicineKurumeJapan

Personalised recommendations