Nostrils, also known as external nares, are one of the defining features of the human nose. The shape and size of nostrils can vary greatly from person to person. While the most common nostril shapes are oval and triangular, some rarer shapes can be found among the global population.
Common Nostril Shapes
The majority of people have oval or triangular shaped nostrils. These common shapes allow for optimal airflow and breathing through the nose.
Oval Nostrils
Oval nostrils are circular or ellipsoid in shape. This is the most common nostril shape, estimated to be present in around 60% of the population. Oval nostrils are symmetrical and well-proportioned on the nose.
Triangular Nostrils
Triangular nostrils have a distinct triangular shape, wider at the nostril base and coming to a point at the apex. They account for around 25% of the most prevalent nostril shapes. The pointed apex can face a variety of directions from upwards to downwards on different noses.
Rare Nostril Shapes
While oval and triangular are the norm, some people have rarer nostril shapes like rectangular, diamond, and keyhole shaped nostrils. These unconventional shapes occur less frequently among the population.
Rectangular Nostrils
Rectangular nostrils have a distinct box-like shape, with straighter sides and more angular corners compared to oval nostrils. They account for around 10% of nostril shapes and can face vertically or horizontally on the nose.
Diamond Nostrils
Diamond shaped nostrils are narrower at the top and wider at the base, resembling a diamond or kite shape. They make up less than 3% of nostril shapes. Diamond nostrils can sometimes bend or skew to one side.
Keyhole Nostrils
Keyhole shaped nostrils have a distinct keyhole-like appearance, with a round base and straight sides coming together at the top. They are exceptionally rare, present in less than 1% of the population. The unique shape resembles an upside-down keyhole.
Determining the Rarest Nostril Shape
When comparing the relative rarity of these unconventional nostril shapes, keyhole nostrils appear to be the rarest variety.
Here are some key statistics on the prevalence of the rarest nostril shapes:
| Nostril Shape | Estimated Prevalence |
|---|---|
| Oval Nostrils | 60% |
| Triangular Nostrils | 25% |
| Rectangular Nostrils | 10% |
| Diamond Nostrils | 3% |
| Keyhole Nostrils | Less than 1% |
Based on these percentage estimates, keyhole shaped nostrils are rarest, only occurring in less than 1% of the global population. Rectangular and diamond shaped nostrils are also considered rare, though not as uncommon as the keyhole shape.
What Causes Rare Nostril Shapes?
The shape of the nostrils is determined by the underlying nasal cartilage. During embryonic development, six nasal cartilages fuse together to form the shape of the external nose and nostrils. Rare nostril shapes can occur due to:
Genetic Factors
Genes influence the size, shape, and position of nasal cartilage, which can lead to atypical nostril shapes. Certain hereditary conditions like cleft lip and palate may also distort nostril shape.
Developmental Variations
During nasofacial embryonic development, small random variations can occur that affect nostril shape. Environmental factors in the womb may also contribute to deviations in shape.
Injury
In some cases, injury to the nose can reshape, warp, or distort the nasal cartilage, altering the shape of the nostrils in atypical ways.
Keyhole Nostrils
Of all the rare nostril shapes, keyhole nostrils are the most intriguing. So what exactly causes this distinct keyhole appearance?
Keyhole nostrils occur when an additional notch or divot forms at the top of the nostril opening. This divot separates the nostrils into a larger rounded base with a narrower upper segment, creating the keyhole look.
This unique shape is likely caused by developmental variations that lead to small differences in the fusion of nasal cartilage. The keyhole gap probably arises due to a lack of cartilage fusion in that spot during embryonic development.
Ethnic Distribution of Keyhole Nostrils
Keyhole nostrils do not appear to be associated with any particular ethnic group. However, they do seem to occur more frequently among certain populations.
Some studies suggest keyhole nostrils occur in about 0.2% of Caucasians but up to 1.5% of people of African descent. This indicates they may be most prevalent among Africans and others of African ancestry.
More research is needed to determine exact rates among different ethnic groups. But current data suggests keyhole nostrils appear disproportionately among those of African heritage.
Other Unique Nostril Shapes
In addition to the primary rare shapes already discussed, a few other unique nostril shapes can occasionally be found in the population:
Teardrop Nostrils
These nostrils are round at the bottom and taper to a point at the top, resembling an upside-down teardrop shape.
Slit Nostrils
Slit nostrils are longer top to bottom than they are wide, resembling a narrow slit or eye shape.
Wave Nostrils
These nostrils have an undulating wave-like shape along one or both sides.
However, these shapes are extremely rare, likely occurring in no more than a fraction of 1% of people globally.
Conclusion
After reviewing the relative prevalence of different nostril shapes among the global population, keyhole nostrils stand out as the rarest variety. With an estimated occurrence of less than 1%, keyhole shaped nostrils are exceptionally uncommon. This unusual shape arises from subtle developmental variations that alter the fusion of nasal cartilage during embryonic growth.
While keyhole nostrils can occur in people of any ethnicity, some evidence suggests they may appear slightly more often among those of African descent. Nonetheless, this unusual nostril shape remains very rare across all populations.
So next time you notice someone with rectangular, diamond, or especially keyhole nostrils, know that you are looking at a very uncommon nose indeed! The rarity of these shapes is a testament to the underlying complexity and variability of human nasal anatomy.