The anatomy of the human nose is made up of bones, cartilage and fibrous fatty tissues. The structure of the upper part of the nose consists of bones; the uppermost portion of the nose near the eye sockets is made up of two nasal bones, which are connected to the frontal bone of the skull (forehead). These two nasal bones join to form the stem of the nose, linked on both sides to a process of the maxilla (upper jaw bone) by a hard, fibrous membrane. At the base, the nasal bones are linked with septal and lateral nasal cartilage. The lower part of the nose is made up of cartilage, which gives the nose its external shape.
Bones and cartilage of the human nose
The nasal bones can be felt between the eyes, while cartilage extends from the middle portion of the nose to its tip. The bridge of the nose extends to form the septum with septal cartilage. The septum separates the two nostrils and extends up into the nasal cavity, where there are three horizontal bones called the nasal conchae which separate the nasal cavity into three dent-like air passages.
These three turbinates are called the inferior, middle and superior based on their position and functions. The play a role in regulating the temperature and humidity (up to 98% water) of the air as well as filtration of the air as it travels through the nasal cavity. On the side of the septal cartilage is the lateral nasal cartilage. Just beneath that is the greater alar cartilage, which is a thin, flexible plate that shapes the medial and lateral walls of the nostrils. In addition to the greater alar cartilage, there are also three or four lesser alar cartilages, which together make up the overall shape of the nostrils.
Inside the human nose
Hairs line the inside of the nostrils, which is important for filtration and humidification of the air we breathe as it passes through them. Indirectly, nose hair plays a role as a defense mechanism against harmful pathogens and solid particulate matter in the air. Both the nostrils and the nasal cavity are lined with mucus membranes and cilia.
The membranes release the sticky substance known as mucus, which along with the cilia help filter the air and prevent any foreign particles such as dust or microorganisms from entering the respiratory system. The mucus also helps humidify the air as it enters the body. Below the mucus membrane are blood capillaries which help to warm the air so that it reaches body temperature by the time it reaches the lungs.