Nasal plane
Planum nasale
Definition
The nasal plane is the most rostral surface of the external nose in domestic carnivores, sheep, and goats. It is hairless, pigmented, and divided by the philtrum, which extends along the midline. Its surface is subdivided into small polygonal areas by grooves, the arrangement of which remains unchanged throughout life and is characteristic of each individual.
In cats and dogs, the nasal planum is protruding around the nostrils, especially dorsally. In sheep and goats, it forms an extended band dorsally to the nostrils.
In cattle, the top of the nose is called the nasolabial plane or muzzle. In pigs, it is the rostral plane or snout.
References
Barone R. Anatomie comparée des mammifères domestiques, Tome 3, Splanchnologie I, 4th edition, Vigot, Paris, 2017.
