A deviated septum can range from completely invisible on the outside to an obviously crooked nose, depending on severity. The septum is the thin wall of cartilage and bone running down the center of your nose, dividing it into two passages. When it shifts to one side, the internal passages become unequal in size, and in more pronounced cases, the external shape of the nose changes too. Most people have some degree of deviation, so what you see (or don’t see) varies widely.
What It Looks Like From the Outside
Mild deviations rarely change the outward appearance of your nose at all. You could have one and never know it just by looking in the mirror. But as the deviation becomes more significant, a few visible signs start to show up.
A severely deviated septum can make the nose look off-center or crooked, with the nasal bridge appearing to curve or lean to one side. The nostrils may look uneven or noticeably different in size. In some cases, the lower edge of the septum (the strip of tissue between your nostrils) sits visibly off the midline, pulling the nasal tip slightly in one direction. These external changes are more common after a nose injury than in people born with a deviation.
What It Looks Like Inside the Nose
The real story of a deviated septum is what’s happening inside, and it’s something you can’t fully see on your own. When a doctor looks into your nostrils using a small handheld instrument that gently spreads them open, they’re checking whether the septum shifts the available space between the two nasal passages. On the side where the septum bows outward, the passage narrows. In mild cases, the septum drifts less than halfway toward the outer wall. In moderate cases, it crosses that halfway point. In severe cases, the septum actually touches the outer wall of the nasal passage, effectively blocking it.
The deviation itself can take different shapes. Some septa have a smooth C-shaped curve to one side. Others have an S-shape, bowing in one direction near the top and the opposite direction lower down. Some have a sharp, angular bend at one specific point, almost like a ridge or spur of cartilage jutting into the airway. That spur can sometimes press directly against the inner wall of the nose, creating a visible point of contact that contributes to pain or obstruction.
What Happens on the Other Side
One of the less obvious visual features of a deviated septum is what happens in the wider nostril, on the opposite side of the deviation. The body compensates for the uneven airflow by enlarging a structure called the inferior turbinate, a curved shelf of bone and tissue along the outer wall of each nasal passage. On the side with more room, this turbinate gradually swells, sometimes substantially. This is the body’s way of preventing too much air from rushing through the open side, which would dry out the lining and disrupt normal airflow patterns.
This compensatory enlargement involves both the soft tissue covering the turbinate and, over time, the bone itself. The result is that even the “good” side of the nose can end up partially blocked. If a doctor looks inside both nostrils, they’ll often see a narrowed passage on one side from the deviated septum and a bulging turbinate on the other. This combination is a hallmark visual pattern of a significant deviation.
How Doctors Evaluate Severity
During an exam, a provider gently opens each nostril and visually inspects how far the septum has shifted. After using a nasal spray to shrink the tissue lining (so the underlying structure is easier to see), they gauge how much of the airway the deviation occupies. The key reference points are simple: how close the most deviated portion gets to the outer nasal wall.
- Mild: The septum drifts to one side but stays within the inner half of the passage.
- Moderate: The septum crosses the midpoint but doesn’t reach the outer wall.
- Severe: The septum touches or nearly touches the lateral wall, leaving little to no open airway on that side.
For a more detailed look, doctors sometimes use a thin, flexible camera (nasal endoscopy) or a CT scan. These tools reveal not just the deviation itself but related problems it causes. As the angle of deviation increases, the drainage pathways for the sinuses on that side are more likely to become blocked. This is why significant deviations often show up alongside chronic sinus issues on imaging, even if the patient came in for a different reason entirely.
What You Might Notice Without a Doctor
If you’re trying to check at home, there are a few things you can look for, though a self-exam has real limits. Stand in front of a well-lit mirror and look straight at your nose. If the bridge has a visible curve, or if one nostril opening looks clearly smaller than the other, those are external hints. You can also gently press one nostril closed and breathe through the other, then switch. A consistent, noticeable difference in airflow between sides suggests something is narrowing one passage, though swollen tissue from allergies or a cold can mimic this.
What you won’t be able to see on your own is how far the septum has shifted inside, whether a bone spur is pressing against the nasal wall, or whether your turbinates have enlarged in response. These internal features are what determine whether a deviation is causing real problems or is just an incidental finding. Up to 80% of people have some degree of septal deviation, and most never need treatment. The deviations that matter are the ones that visibly compress or block the airway when a provider looks inside.