Nose is the most prominent feature located in the middle of the face of humans. An organ of the upper respiratory tract, it is actively involved in inhalation. The most important functions of nose are to filter the atmospheric air before passing it further into the respiratory system and to provide the sense of smell. In fact, it acts as an interface between the air of the body's respiratory passage and the atmospheric air. At the time of breathing, air entering through the nostrils is led to the nasal cavity, which further passes to the pharynx, trachea, bronchi, and finally, to the lungs.
The Human Nose: Anatomy and Structure
The structure of a human nose is composed of bones, cartilage, and fibrofatty tissues. And the external feature of a nose or the type of nose depends upon the bone and cartilage. According to the shapes and sizes of human nose, they can be classified into different types such as the Roman or aquiline, the Greek or straight, the Nubian, the hawk, the snub, and the turn up types. Human races can be identified by the type of nose; for example, the Europeans have long, narrow, large elevation (height of the nose tip above the lip), and vertically set nostrils.
Supporting structure of the upper part of nose is mostly made up of bones. The topmost portion near the eye sockets consists of two nasal bones, which is linked to the frontal bone of the forehead. These nasal bones are joined to form the nose bridge. On the sides, they are connected with the lateral process of the maxilla by a tough fibrous membrane. At the base, nasal bones are connected with septal and lateral nasal cartilage. The lower part of the nose is made up of cartilages. These cartilages give shape to the external feature of the nose.
To speak in simple words, the nasal bone can be felt in between the eyelids, while the cartilage extends from the nose tip to the middle portion. Coming to the nasal septum, the nose bridge continues with the septal cartilage to form the septum. As we all know, the nasal septum separates the nostrils, which in turn, continue with the nasal cavity. Again, there are three horizontal outgrowths of bones, called turbinate or conchae that divide the nasal cavity into three groove-like air passages. Main purpose of conchae is to increase the surface area of the nasal cavity.
The three turbinates are named as inferior, middlen and superior turbinates, according to their position and functions. They are also important for maintaining the temperature, humidification (up to 98% water saturation), and filtration of the air when it travels the nasal cavity. On either side of the septal cartilage, there lies the lateral nasal cartilage.
Just below the lateral nasal cartilages, the greater alar cartilage is present, which is a thin, flexible plate that forms the medial and lateral wall of the nostril. In addition to greater alar cartilages, there are three or four small cartilages that are called lesser alar cartilages. Both the greater and lesser alar cartilages give the overall shape of the nostrils.
Hair are present inside the nostrils, which play a major role in filtration and humidification of atmospheric air as it passes them. Indirectly, nose hair serve as a defense mechanism against the harmful pathogens and solid particulate matter present in the air. Both the nostrils and nasal cavity are lined by mucous membrane and cilia. The membrane secretes a sticky substance called mucus.
Together, this mucus and cilia filter the air and prevent entry of foreign particles such as microorganisms, dust, and particulate matter inside the respiratory system. The mucus also helps in moistening the air. Underneath the mucous membrane, there are blood capillaries that warm the air so that it matches the body temperature.
You might have already heard about the sinuses and sinus infections. The bones of the face around the nose region contain the sinuses. Anatomically, sinuses are hollow air cavities that are lined by mucous membrane (similar to the nasal cavity), and they are also known as paranasal sinuses. There are four subgroups of sinus, classified based on the bones to which the sinuses are present. They are frontal, maxillary, ethmoid, and sphenoid sinus. Among these four sinuses, ethmoid sinus is located around the area of nose bridge. An abnormality in any of these paranasal sinuses cause sinus problems.
To sum up, nose is responsible for respiration and olfactory perception. At present, nose surgery or rhinoplasty is performed to improve the appearance, and also, to correct medical problems related to the bone, which impair the respiration process. People with deviated septum frequently participate the procedure. This septum condition may be present at birth or may be resulted due to an accident. Giving satisfactory results in terms of improved appearance and function, nose surgery has become an important procedure in the field of cosmetic or plastic surgery.