The nasal septum is the thin, dividing wall that separates the right and left nasal passages. This structure is intended to run straight down the center, creating two equally sized airways. A deviated septum occurs when this wall is displaced or crooked. Most people live with some degree of septal misalignment, but only a fraction experience problems that require attention.
Anatomy of the Nasal Septum
The septum is a complex structure composed of both bone and cartilage, which provides both rigidity and flexibility. The anterior portion, located near the tip of the nose, is formed by the septal cartilage, often called the quadrangular cartilage. This cartilaginous section is resilient and gives the septum its ability to flex slightly.
The deeper, posterior part of the septum is constructed from bone, primarily the perpendicular plate of the ethmoid bone and the vomer bone. The vomer forms the lower-back section, connecting to the floor of the nasal cavity. The perpendicular plate forms the upper-back section, extending toward the skull base.
Prevalence of Deviation
A perfectly straight nasal septum is anatomically uncommon; some degree of deviation is present in the majority of the population. Studies suggest that up to 80% of individuals have a septum that is at least slightly off-center. This high prevalence indicates that a minor misalignment is often considered a normal anatomical variation rather than a medical condition.
The displacement often develops naturally during growth, as the bony and cartilaginous components expand at different rates. Many people are unaware they have a deviation because the misalignment is too minor to block airflow or cause noticeable symptoms. Only a small percentage of people experience a severe bend or obstruction that interferes with breathing, which is considered a functionally significant deviation.
When a Deviated Septum Requires Attention
A deviated septum becomes a medical concern when the displacement is severe enough to cause functional consequences. The most common symptom is chronic nasal obstruction, where one or both nostrils feel persistently blocked, making it difficult to breathe through the nose. This is often worse on the side toward which the septum is deflected.
The altered airflow can also lead to frequent nosebleeds, known medically as epistaxis. The turbulence caused by the obstruction dries out the mucosal lining on the narrower side, making the tissue more fragile and prone to bleeding. Severe deviations can also impair the drainage of the sinuses, contributing to recurrent or chronic sinus infections. The constant struggle for airflow can manifest as facial pain, headaches, noisy breathing during sleep, or the development of obstructive sleep apnea. When these symptoms significantly affect a person’s quality of life, the condition may warrant medical evaluation. Surgical correction, called septoplasty, is reserved for these functionally significant cases, where the goal is to physically straighten the septum by trimming or reshaping the bone and cartilage.