What is triradiate cartilage?

Triradiate cartilage, also known as alar cartilage, is a piece of cartilage that is at the tip of the human nose between the two nasal passages of the nostrils. It is named from its three-forked structure, with the medial crus extending medially to meet the nasal septum, the intermediate crus extending forward between the lateral and medial crura, and the lateral crus forming the lateral portion of the alar (nostril) margin.

Together with nasal septum, major alar cartilage contributes to the definition of the nose tip structure and function of the nostril. There are also two or three minor cartilages (alar cartilage minor), sesamoid in arrangement which lie on the internal side of the major cartilage.