The nasal septum () separates the left and right airways of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the human nose, nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. ...

, dividing the two

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

s. It is depressed by the

depressor septi nasi muscle The depressor septi nasi muscle (or depressor alae nasi muscle) is a muscle of the face. It connects the incisive fossa of the maxilla and the orbicularis oris muscle to the nasal septum of the nose. It draws the ala of the nose downwards, ...

Structure

The fleshy external end of the nasal septum is called the

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

or columella nasi, and is made up of cartilage and soft tissue. The nasal septum contains bone and hyaline cartilage. It is normally about 2 mm thick. The nasal septum is composed of four structures: *

Perpendicular plate of ethmoid bone The perpendicular plate of the ethmoid bone (vertical plate) is a thin, flattened lamina, polygonal in form, which descends from the under surface of the cribriform plate, and assists in forming the septum of the nose; it is generally deflected ...

* Vomer bone *

Septal nasal cartilage The septal nasal cartilage (cartilage of the septum or quadrangular cartilage) is composed of hyaline cartilage. It is somewhat quadrilateral in form, thicker at its margins than at its center, and completes the separation between the nasal cav ...

Maxillary bone The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

(the crest) The lowest part of the septum is a narrow strip of bone that projects from the maxilla and the palatine bones, and is the length of the septum. This strip of bone is called the maxillary crest; it articulates in front with the septal nasal cartilage, and at the back with the vomer. The maxillary crest is described in the anatomy of the nasal septum as having a maxillary component and a palatine component.

Development

At an early period, the septum of the nose consists of a plate of cartilage, known as the ''ethmovomerine cartilage''. The postero-superior part of this cartilage is

ossified Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

to form the perpendicular plate of the

ethmoid The ethmoid bone (; from grc, ἡθμός, hēthmós, sieve) is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a ...

; its antero-inferior portion persists as the septal cartilage, while the

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right max ...

is ossified in the membrane covering its postero-inferior part. Two

ossification center An ossification center is a point where ossification of the cartilage begins. The first step in ossification is that the cartilage cells at this point enlarge and arrange themselves in rows.Gray and Spitzka (1910), page 44. The matrix in which t ...

s, one on either side of the middle line, appear about the eighth week of fetal life in this part of the membrane, and hence the vomer consists primarily of two lamellae. About the third month these unite below, and thus a deep groove is formed in which the cartilage is lodged. As growth proceeds, the union of the lamellae extends upward and forward, and at the same time the intervening plate of cartilage undergoes absorption. By the onset of

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a bo ...

the lamellae are almost completely united to form a median plate, but evidence of the bilaminar origin of the bone is seen in the everted alae of its upper border and in the groove on its anterior margin.

Clinical significance

The nasal septum can depart from the centre line of the nose in a condition that is known as a

deviated septum Nasal septum deviation is a physical disorder of the nose, involving a displacement of the nasal septum. Some displacement is common, affecting 80% of people, mostly without their knowledge. Signs and symptoms The nasal septum is the bone and ...

caused by trauma. However, it is normal to have a slight deviation to one side. The septum generally stays in the midline until about the age of seven, at which point it will frequently deviate to the right. An

operation Operation or Operations may refer to: Arts, entertainment and media * ''Operation'' (game), a battery-operated board game that challenges dexterity * Operation (music), a term used in musical set theory * ''Operations'' (magazine), Multi-Ma ...

to straighten the nasal septum is known as a

septoplasty Septoplasty �sɛp.toˌplæ.sti(Etymology: L, saeptum, septum; Gk, πλάσσειν plassein – to shape), or alternatively submucous septal resection and septal reconstruction, is a corrective surgical procedure done to straighten a deviated ...

. A perforated nasal septum can be caused by an

ulcer An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...

, trauma due to an inserted object, long-term exposure to

welding fumes Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as brazi ...

, or

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

use. There is a procedure that can be of help to those suffering from perforated septum. A silicone button can be inserted in the hole to close the open sore. The nasal septum can be affected by both

benign tumor A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize (spread throughout the body). Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have re ...

s such as

fibroma Fibromas are benign tumors that are composed of fibrous or connective tissue. They can grow in all organs, arising from mesenchyme tissue. The term "fibroblastic" or "fibromatous" is used to describe tumors of the fibrous connective tissue. Whe ...

s, and

hemangioma A hemangioma or haemangioma is a usually benign vascular tumor derived from blood vessel cell types. The most common form, seen in infants, is an infantile hemangioma, known colloquially as a "strawberry mark", most commonly presenting on the ski ...

s, and

malignant tumor Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal ble ...

s such as squamous cell carcinoma.

Cosmetic procedures

A nasal septum piercing is usually carried out through the fleshy columella close to the end of the nasal septum.

References

External links

* – "Diagram of skeleton of medial (septal) nasal wall"
Diagram at evmsent.org
* () {{Authority control Nose