In this article we cover nasal septum anatomy, providing a plain English explanation of what a septum is, how it becomes deviated, and other key questions.
We’ve also included lots of diagrams, so you can “see” what we’re talking about!
Where is the Septum?
A “septum” is a wall-like structure that divides cavities into smaller sections. It is found in different parts of our body.
For instance, a septum divides our heart into 4 chambers, and inter-muscular septum divides muscles in our hands and legs.
The septum acts as a barrier. In the case of your heart, the septum helps avoid intermixing of deoxygenated blood in the right chambers with the oxygenated blood in the left.
Similarly, the septum in our nose divides the nose into two halves, which open externally as nostrils.
The presence of a septum in the nasal cavity aids in the smooth transition of airflow from nostrils into the nasal cavity to the lungs. It also provides structural support to the nose.
Nasal Septum Bones: Which Bones Make Up the Nasal Septum?
The septum in your nose is composed of cartilage and bones. The movable and flexible part at the front of the nasal septum is made up of cartilage.
The nasal septum is supported by two bones, the ethmoid bone on top and the vomer bone sitting behind the cartilage and ethmoid bone. The tip of the maxillary bone, palatine bone, and other soft tissues support the nasal septum.
The mucosal lining (skin covering the septum) shelters and protects the septum, and also helps keep the nose moist from inside.1Drake, R., Vogl, W., Mitchell, A. and Gray, H., 2005. Gray's Anatomy For Students. Philadelphia: Elsevier/Churchill Livingstone.
What is a Deviated Nasal Septum (DNS)?
The nasal septum should ideally divide your nose into equal halves. But for most humans, the nasal septum tends to be placed toward the left or right, away from the center. This leads to a difference in the size of the nasal halves, and is commonly known as a deviated nasal septum.2Teixeira, Jeffrey et al. “Nasal Septal Deviations: A Systematic Review of Classification Systems.” Plastic surgery international vol. 2016 (2016): 7089123. doi:10.1155/2016/7089123
What Does a Deviated Septum Look Like?
A deviated nasal septum can develop during fetal development, birth, or later in life. Deviated nasal septum deformities can largely be classified into two types—cartilaginous and combined septal deformity:
C-shaped versus S-shaped deviated nasal septum
Septum Size: How Big is the Nasal Septum?
The cartilage part of the septum is ~3.3 cm in length and ~3.0 cm in height. Its thickness is ~2 mm.4Hwang K, Huan F, Kim DJ. Mapping thickness of nasal septal cartilage. J Craniofac Surg. 2010;21(1):243‐244
The surface area of the cartilaginous septum is ~32% of the total septum.5Kim, In-Sang et al. “Analysis of the Development of the Nasal Septum according to Age and Gender Using MRI.” Clinical and experimental otorhinolaryngology vol. 1,1 (2008): 29-34.
The dimensions of the septum vary for each individual and vary directly with the dimensions of the nose.
Deviated Septum & Genetics: Is a Deviated Septum Genetic?
It is commonly believed that deformities in the frontal region of the septum (cartilage area) are due to injury, including during pregnancy or birth. Meanwhile, deformities in the posterior region (involving the ethmoid and vomer bones) could be of a genetic origin.6Mladina R, Subarić M. Are some septal deformities inherited? Type 6 revisited. Int J Pediatr Otorhinolaryngol. 2003;67(12):1291‐1294
How Common is a Deviated Septum?
A straight nasal septum is present only in 7-20% of adults. This means more than 80 out of 100 people have some degree of deviated nasal septum! A few studies have found a prevalence of DNS up to ~90% in humans. However, not all DNS cases show symptoms.
Prevalence of Deviated Nasal Septum by age-group 7Reitzen SD, Chung W, Shah AR. Nasal septal deviation in the pediatric and adult populations. Ear Nose Throat J. 2011;90(3):112‐115.
Can a Deviated Septum Get Worse?
The cartilaginous septum reaches adult dimensions at the age of two years. With aging, the septal cartilage decreases in size and the bony part increases. This increases the chances of the septal deformity becoming more prominent, and even symptomatic.
A deviated septum can lead to nasal obstruction and congestion, which forces the patient to breath from their mouth, causing drying of mouth, pharynx, and larynx. This further promotes the incidence of cold, bronchitis, and sore throat. Other symptoms include:
In mild septal deviation cases, the presence of sinus infection or bronchitis may amplify the symptoms.
In infants, who tend to breathe through their nose, nasal obstruction leads to cyanosis (skin turning blue due to lack of oxygen), high lung resistance, and even respiratory failure. More commonly, nasal obstruction leads to difficulty in feeding and colic (pain in the abdomen).8Moorthy, P. , Kolloju, S. , Madhira, S. and Jowkar, A. (2014) Clinical Study on Deviated Nasal Septum and Its Associated Pathology. International Journal of Otolaryngology and Head & Neck Surgery, 3, 75-81.
- 1Drake, R., Vogl, W., Mitchell, A. and Gray, H., 2005. Gray's Anatomy For Students. Philadelphia: Elsevier/Churchill Livingstone.
- 2Teixeira, Jeffrey et al. “Nasal Septal Deviations: A Systematic Review of Classification Systems.” Plastic surgery international vol. 2016 (2016): 7089123. doi:10.1155/2016/7089123
- 3Gray LP. Deviated nasal septum. Incidence and etiology. Ann Otol Rhinol Laryngol Suppl. 1978;87(3 Pt 3 Suppl 50):3‐20
- 4Hwang K, Huan F, Kim DJ. Mapping thickness of nasal septal cartilage. J Craniofac Surg. 2010;21(1):243‐244
- 5Kim, In-Sang et al. “Analysis of the Development of the Nasal Septum according to Age and Gender Using MRI.” Clinical and experimental otorhinolaryngology vol. 1,1 (2008): 29-34.
- 6Mladina R, Subarić M. Are some septal deformities inherited? Type 6 revisited. Int J Pediatr Otorhinolaryngol. 2003;67(12):1291‐1294
- 7Reitzen SD, Chung W, Shah AR. Nasal septal deviation in the pediatric and adult populations. Ear Nose Throat J. 2011;90(3):112‐115.
- 8Moorthy, P. , Kolloju, S. , Madhira, S. and Jowkar, A. (2014) Clinical Study on Deviated Nasal Septum and Its Associated Pathology. International Journal of Otolaryngology and Head & Neck Surgery, 3, 75-81.
- 9Anatomical variation of the nasal septum: Analysis of 57 cadaver specimens:
- 10What, if any, is the value of septal surgery?
- 11Common site, Etiology, and Solutions of Persistent Septal Deviation in Revision Septoplasty.
- 12Relationship between the degree and direction of nasal septum deviation and nasal bone morphology
- 13Effectiveness of septoplasty versus non-surgical management for nasal obstruction due to a deviated nasal septum in adults: study protocol for a randomized controlled trial
- 14Olfaction and quality of life in patients with nasal septal deviation treated with septoplasty
- 15Techniques in Septoplasty: Traditional Versus Endoscopic Approaches.
- 16Septoplasty Versus Non-Surgical Management for Nasal Obstruction Due to a Deviated Nasal Septum in Adults: A Modelling Study of Cost-Effectiveness.
- 17Nasal Septum and External Nasal Deformity Similarities in Monozygotic Twins and Paranasal Computed Tomography Analysis
- 18Nasal crest - Crista nasalis
- 19Bones of the skull
- 20The Ethmoid Bone
- 21Caudal septum defect.
- 22The Clinical Analysis of the Nasal Septal Cartilage by Measurement Using Computed Tomography.
- 23The Dimensions of the Nasal Septal Cartilage: A Preliminary Study in Adult Filipino Malay Cadavers.
- 24Analysis of the Development of the Nasal Septum according to Age and Gender Using MRI.
- 25Relationship between the degree and direction of nasal septum deviation and nasal bone morphology.
- 26Nasal septal deviation in the pediatric and adult populations
- 27Are some septal deformities inherited?: Type 6 revisited.
- 28Septoplasty can Change the Shape of the Nose.
- 29Preliminary Deformational Studies on a Finite Element Model of the Nasal Septum Reveals Key Areas for Septal Realignment and Reconstruction.
- 30Cadaveric and Engineering Analysis of the Septal L‐Strut.
- 31The Incidence of Nasal Septal Deviation and Its Relation With Chronic Rhinosinusitis in Patients Undergoing Functional Endoscopic Sinus Surgery.
- 32Nasal Septum Deviation