The long, narrow and curled bone shelf that protrudes into the breathing passage of the nose are called the nasal concha. The nasal concha, or also called turbinates divides the nasal airway into 4 passages. One of the passages is where the inhaled air passes through to the nasal mucosa which cleans the air in preparation for the lungs. It is the function of the nasal concha to regulate the pattern of breathing of humans and animals. The defining characteristic of the turbinates are the spongy bones in the nose.