Deviated Septum: Aetiology, Classification, Symptoms, Diagnosis and Treatment

Afanasyeva D. Otorhinolaryngologist

November 13, 2025 · 9 min read

Nasal septum deviation may be a congenital or acquired condition. It occurs when the bony and/or cartilaginous structures of the nasal septum deviate from their median position and disturb the breathing function.

Etiology

Nasal septum deformities may be either congenital or acquired conditions.

The septum may become deformed due to nasal injuries associated with birth trauma, sports, or everyday activities.

The main reason for deformities in children and adolescents is the difference in growth rates of the cartilaginous and bony parts of the nasal septum.

Anatomy and classification of nasal septum deviations

Classification by shape and location

Depending on the shape and location, there are several main types of nasal septum deviation:

The crest of the nasal septum: a sloping thickening along the bony and/or cartilaginous parts of the septum covered with mucosa. It generally appears as a deformed quadrangular cartilage that overlaps the vomer.

Crest of nasal septum — The crest of the nasal septum: 3D-model

Nasal septum spur: a sharp, narrow bony protrusion directed towards the side wall of the nose. Sometimes it can be so large that it reaches the nasal conchae.
C-shaped deviation: the septum curves in an arc to one side of the nasal cavity.
S-shaped deviation: the septum curves in a wave-like manner to both sides.

Both types of deviations (C- and S-shaped) are associated with an excessively large quadrangular cartilage. Because of its size, it does not fit into the bony bed between the perpendicular plate of the ethmoid bone, maxilla, and palatine bone.

Mladina’s classification

The Mladina’s classification includes 7 types of nasal septal deformities that are widely used by rhinologists:

Type 1: a unilateral vertical ridge in the area of the nasal valve that does not reach it.
Type 2: a unilateral vertical ridge that reaches the nasal valve, reducing its angle.
Type 3: a unilateral ridge in the deeper parts of the nose, at the level of the middle part of the middle turbinates.
Type 4: bilateral deviation, in which type 2 deformity is observed on one side and type 3 deformity (S-shaped deformity in depth) on the other.
Type 5: a unilateral bony or bony-cartilaginous spur, with the opposite side of the septum being flat.
Type 6: a bony spur on one side, accompanied by a pronounced depression (cavity) in the septum on the other side.
Type 7: a combination of several types, known as a “crushed” septum.

Clinical presentation of nasal septum deviations

Clinical presentation depend on the degree of a deviation:

Nasal functions are not significantly affected if deviations from the midline are mild or crests are small.
However, pronounced deviations (types 3–7 according to Mladina’s classification) and large spurs and crests impair nasal breathing and lead to frequent sinusitis, chronic infections and snoring. Patients may also experience nosebleeds, headaches, and impaired sense of smell.

Diagnosis of nasal septum deviations

Diagnosis is based on rhinoscopy and nasal endoscopy results. A CT scan of the facial bones helps assess the deviation (both bony and cartilaginous tissues), its length, and evaluate the paranasal sinuses.

Treatment of nasal septum deviations

The condition may be corrected surgically via septoplasty.

FAQ

1. What are the causes of nasal septum deviation, including in children?

The causes may be congenital or acquired. Most often, this is a consequence of injuries to the nose — birth injuries, domestic injuries, or sports injuries. In children and adolescents, deviation also often occurs due to uneven growth of the bone and cartilage parts of the septum during the development of the facial skeleton.

2. What symptoms does a deviated septum cause and what does it affect?

The main symptom is persistent difficulty in nasal breathing on one or both sides. This, in turn, affects quality of life, leading to chronic sinusitis (maxillary sinusitis, frontal sinusitis), frequent nosebleeds, snoring, headaches, and a reduced sense of smell. With minor deviation, there may be no symptoms.

3. What are the risks of a deviated septum and what are its consequences?

The main risk lies in chronic disruption of the physiology of the nose. Long-term consequences include frequent recurrent inflammatory diseases of the sinuses (sinusitis), chronic infectious processes in the respiratory tract, and the development or worsening of snoring, which may be associated with obstructive sleep apnoea syndrome.

4. What does a deviated septum look like, and what types are known?

During a visual examination (rhinoscopy), the physician can see various types of deformities. This may be a crest (a slight thickening), a sharp spur directed towards the lateral wall of the nose, or a general deviation of the septum in the shape of letters “C” or “S.” There are also more detailed classifications, such as Mladina’s, which divides deformities into 7 types.

5. How is a deviated septum corrected?

Correction of the deformity is only possible through surgery. It is called septoplasty. During the procedure, the surgeon reshapes the cartilage and bone structures, placing the septum in a central position to restore full nasal breathing.

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