Nose hole

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Nostrils and hairs of man

The nostrils (Latin nares , singular naris ; syn. Nasal opening , aperture nasi ) are the two rounded front openings of the nose , more precisely of the nasal vestibule ( vestibulum nasi ). They are bounded laterally by the nostrils ( alae nasi ) and in the middle by the nasal septum ( septum nasi ). The nostrils are supported by different types of cartilage and are therefore mobile. They allow air and fragrances to pass through to the olfactory mucosa .


In modern humans and also in Homo erectus , the nostrils point downwards. They can be narrowed and widened by the bilateral nasal muscle . Its pars transversa (transverse part) acts like a sphincter, the pars alaris (wing part) only moves the nostrils. The delicate levator labii superioris alaeque nasi muscle also widens the nostril, whereas the depressor septi nasi muscle pulls the nasal septum downwards and thus, like the depressor alae muscle (syn. M. myrtiformis ), narrows the nostril. The muscles only play a subordinate role in regulating the width of the nostril in humans, but they participate in facial expressions and thus in expressing feelings. The large horseshoe-shaped nasal cartilage ( cartilago alaris major ) frames the nasal opening and attaches itself to the nasal septum with its leg towards the middle. This creates a ledge-shaped elevation ( Limen nasi ). This point is also known as the “inner nostril”. In addition, three to four smaller alar cartilages ( cartilagines alares minores ) stabilize the nostrils on both sides . The nostril is protected from foreign bodies by protective hairs ( vibrissae ).

With a septal deviation , one nostril can be larger than the other. With septum piercing , the piercing is pierced through the nasal septum and protrudes from the nostrils.

Other mammals

In the other mammals, the nostrils are also supported by nasal cartilage ( cartilagines nasi externi ). The movable part of the nasal septum ( pars mobilis septi nasi ) continues above and below into the side wall cartilage ( cartilagines nasi laterales dorsales and ventrales ). In addition, there is an additional cartilage directed towards the middle ( cartilago nasalis medialis accessoria ), in sheep, predators and pigs there is also an additional lateral cartilage ( cartilago nasalis lateralis accessoria ). The nostrils are widened by the levator nasolabialis muscle , and also by the caninus muscle in horses . The musculus dilatator nasi apicalis and the musculus lateralis nasi are mainly developed in horses and ruminants and also serve to widen the nostril. The separate air currents through the two nostrils seem to play a role in spatial smelling .

In horses , the nostrils are also known as nostrils . The dorsal sidewall cartilage is only slightly developed, the ventral one is completely absent. As a result, the side edge of the nostril is without any cartilaginous support ("soft nose"). The comma-shaped alar cartilage ( cartilago alaris ) extends from the tip of the nasal septum and supports the nasal opening above, below and towards the middle. The inner nostril protrudes as a wing fold ( Plica alaris ) into the upper nostril angle, so that the nostril has a crescent moon shape during normal breathing. Only when breathing is forced does the nostril expand and assume a round shape. Above the wing fold, the nostril ends blindly ("false nostril") in the "nasal trumpet" ( diverticulum nasi ). This must be taken into account when inserting a nasogastric tube.

In dogs , the nostrils lie on the nasal mirror and are round. They run out to the side in a slit. Congenital narrowing of the nostrils is particularly common in brachycephalic dog breeds. This can severely hinder inhalation ( inspiratory dyspnea ), so that surgical nostril widening may be necessary.

In rodents and lagomorphs the nostrils are in the range of the tactile perception serving Narialkissen .

In whales , the nostril is called the blowhole because it creates a fountain of mist ( blow ) when you exhale . While toothed whales only have one blowhole, baleen whales have two.

Birds, reptiles and amphibians

Nose opening in a budgie: the conspicuously colored area is known as wax skin and is blue in males.

In birds , the nostrils are at the base of the beak , only in kiwis at the tip of the beak. In many ducks, the nasal septum is perforated in the area of ​​the nares ( nares perviae ), in the other birds it is not ( nares imperviae ).

In reptiles , the two nostrils are usually near the tip of the snout. In many aquatic reptiles, they can be locked and thus prevent water from entering when diving. In crocodiles , the nostril is surrounded by a closed ring of circular muscle fibers that form a sphincter muscle ( musculus constrictor naris ). This is traversed by a bundle of longitudinal muscle fibers, which represent the nostril widener ( Musculus dilatator naris ). When the nostril is as wide as possible, the nostril is round, while when it is narrowed, the rear wall is pulled forward so that the edges of the nostrils show a sloping sickle shape.

The nostrils of amphibians can also be closed. The closure also allows any sound bubbles that may be present to be inflated .

Individual evidence

  1. ^ A b Johannes W. Rohen, Elke Lütjen-Drecoll: Functional anatomy of humans: textbook of macroscopic anatomy according to functional aspects . Schattauer Verlag, 2006, ISBN 978-3-7945-2440-2 , pp. 176-177.
  2. ^ A b c Richard Nickel, August Schummer, Eugen Seiferle: Textbook of the anatomy of domestic animals , Volume 2: Guts . Georg Thieme Verlag, 2004, ISBN 978-3-8304-4152-6 , p. 227.
  3. ^ Jochen Fanghänel, Franz Pera, Friedrich Anderhuber, Robert Nitsch: Waldeyer - Anatomie des Menschen . Walter de Gruyter, 17th edition 2009, ISBN 978-3-11-022104-6 , p. 313.
  4. Bahman Guyuron: Soft Tissue Functional Anatomy of the Nose . In: Aesthetic Surgery Journal Volume 26, Issue 6, November 2006, pp. 733-735. ( Full text )
  5. ^ Salomon et al .: Anatomy for Veterinary Medicine. Enke Stuttgart. 3rd ext. Edition 2015, ISBN 978-3-8304-1288-5 , pp. 166-167.
  6. a b Salomon et al .: Anatomy for veterinary medicine. Enke Stuttgart. 3rd ext. Edition 2015, ISBN 978-3-8304-1288-5 , p. 328.
  7. Manfred Ade: Macroscopic investigations on the Rhinarium of the Glires (Rodentia and Lagomorpha) . Science and technology, Berlin 1998, ISBN 3-89685-463-1 , p. 68 .
  8. Wilfried Westheide, Gunde Rieger: Special Zoology. Part 2: vertebrates or skulls . 2nd Edition. Springer, Berlin 2009, ISBN 978-3-8274-2220-0 , pp. 665 .
  9. Bernd Vollmerhaus: Textbook of the anatomy of domestic animals , Volume 5: Anatomy of birds . Georg Thieme Verlag, 2004, ISBN 978-3-8304-4153-3 , p. 159.
  10. Konrad Herter: Chordatiere IV: Kriechtiere (Chordatiere) . Walter de Gruyter , 2019, ISBN 978-3-11-084364-4 , p. 64.
  11. ^ AD Bellairs and CC Shute: Observations on the narial musculature of Crocodilia and its innervation from the sympathetic system. In: Journal of anatomy. Volume 87, Number 4, October 1953, pp. 367-378, PMID 13117755 , PMC 1244620 (free full text).
  12. Dieter Glandt: Amphibians and Reptiles: Herpetology for Beginners . Springer-Verlag, 2016, ISBN 978-3-662-49727-2 , p. 68