Nasal concha

In anatomy, a nasal concha (/ˈkɒnkə/), plural conchae (/ˈkɒnki/), also called a turbinate or turbinal, is a long, narrow, curled shelf of bone that protrudes into the breathing passage of the nose in humans and various animals.The conchae are shaped like an elongated seashell, which gave them their name (Latin concha from Greek κόγχη). A turbinate bone is any of the scrolled spongy bones of the nasal passages in vertebrates.

In humans, the turbinates divide the nasal airway into 4 groove-like air passages, and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface area of nasal mucosa, which, as a ciliated mucous membrane with shallow blood supply, cleans and warms the inhaled air in preparation for the lungs.

A rapidly dilating arteriolar circulation to these bones may lead to a sharp increase in the pressure within, in response to acute cooling of the body core. The pain from this pressure is often referred to as "brain freeze", and is frequently associated with the rapid consumption of ice cream. The shallowness of the venous blood supply of the mucosa contributes to the ease with which nosebleed can occur.