Alar groove
Sulcus alaris
Definition
The alar fold is a bulb located inside the nostrils.When the dog inhales air, the bulb opens completely to allow a good circulation inside the nose (it contibutes to the olfaction).When exhaling, the bulb closes the upper part; it creates a vortex and directs the air downwards using the slits.This creates a suction system that allows dogs to inhale even more odorous air and thus stirs up the particles to take more odour information.
References
