The nasal cavity consists of two channels separated by osteo-cartilage of the nasal septum. They communicate with the outside through the nostrils and open up to the back in the nasopharynx at the center of the choanae.
The side wall of the nasal cavities has an irregular surface: It actually has 3 sheets of bone (sometimes 4) covered with mucous membrane. Each nasal cavity will have a lower, center, and upper nostril and sometimes a top nostril.
The spaces under the nostrils are called meati, which are where the paranasal sinuses transmit signals.
The paranasal sinuses are pneumatic facial mass cavities that develop during the first few years of life and are consistent with the nasal drops. They include:
The nose has a number of functions:
Several hypotheses have been made on the function of paranasal sinuses: