The nose is composed of bones, cartilage, mucous membranes and skin. It has the physiological functions of sense of smell and conditioning inhaled air before it reaches the lungs. The nose is essentially a complex set of passages and openings between the nares (nose holes) and throat. The bony structure of the nose is complex and supports this network of openings and passageways that aid its physiological function.
External Portions of the Nose
The nose that is visible is supported by the septum and the surrounding bones of the face. The septum is made of cartilage at the tip of the nose, while the bridge of the nose is formed from two nasal bones joined to the frontal bone at the top. The sides and root of the nose are portions of the maxillary bone.
Upper and Deep Nasal Cavity
The roof of the nasal cavity is composed of the nasal, frontal, ethmoid and sphenoid bones. The deep internal wall of the nose is formed by the ethmoid, sphenoid and pterygoid bones. Deep in the nose and behind the nasal cavity are the ethmoid and sphenoid sinuses. The frontal sinus is located above the eyes in the frontal bone. The ethmoid sinus is located between the eyes and the spenoid sinus is located deep above the throat.
Lower and Lateral Nasal Cavity
The floor of the nasal cavity is composed of portions of the maxilla and the palitine bone. The sides of the nose are bordered by the maxilla. There are maxillary sinuses on either side of the nose, located below the eyes, called maxillary sinuses.
Central Nasal Cavity
The septum separates the left and right sides of the nose. This structure is composed of the nasal, ethmoid and vomer bones as well as the septal cartilage and maxilla at the root. The ethmoid sinuses are centrally located just behind the septum.
There are structures called conchae which form shelves within each side of the nose. The upper two conchae are projections of the maxillary bone and the lower is a separate bane called the inferior concha. These structures increase the surface area of the internal nasal cavity, improving the air conditioning function of the nose.
References
- "Gray's Anatomy: The Anatomical Basis of Clinical Practice;" Susan Standring (Editor); 2008
- University of California San Diego: Anatomy of the nasal cavity
