The nose, while appearing as a single structure, is composed of several distinct anatomical areas known as nasal subunits. Understanding these components is fundamental to appreciating the nose’s complexity and its role in facial aesthetics and function. This concept, first described by Dr. Fernando Ortiz-Monasterio and Dr. Gustavo Gonzalez-Ulloa in the mid-20th century, allows for a more precise analysis and treatment of nasal deformities or defects in reconstructive and aesthetic nasal surgery.
The Distinct Areas of the Nose
The nose is divided into nine primary aesthetic subunits, each with unique characteristics of skin quality, contour, and underlying support. The dorsum, or bridge, extends from between the eyes down to the tip, forming the central ridge. Flanking the dorsum are the paired sidewalls, relatively flat surfaces that transition into the cheeks.
The nasal tip is a complex, convex area that defines the most projecting part of the nose. Below the tip, the columella forms the narrow strip of skin and cartilage separating the nostrils. On either side of the columella are the paired alar lobules, which create the rounded, flared appearance of the nostrils.
The paired soft triangles are small, concave areas located just above the alar lobules and below the nasal tip. These subtle depressions contribute to the natural contours of the lower nose. Skin thickness varies across these subunits; for example, the nasal tip and alae tend to have thicker skin, while the mid-lower dorsum and upper sidewalls have thinner skin.
Significance for Appearance and Breathing
The distinct nasal subunits are important because their harmonious relationship and proportionality contribute to the overall aesthetic balance of the nose and face. Each subunit possesses unique contours, curvatures, and light reflections that define the nose’s natural appearance. Even subtle changes or damage to one subunit can disrupt this balance, leading to noticeable asymmetry or an unnatural look. For instance, an improperly contoured alar lobule can alter the shape of the nostril, impacting facial symmetry.
Beyond aesthetics, the proper structure and relationship of these subunits are also directly tied to breathing function. The internal architecture of the nose, formed by these subunits, dictates the patency of the nasal airways. Issues like a deviated septum, where the wall between the nostrils is crooked, or nasal valve collapse, affecting the narrowest part of the airway, can significantly obstruct airflow.
Enlarged turbinates or nasal polyps can further reduce the ability to breathe clearly. When nasal airflow is compromised, individuals may resort to mouth breathing, experience increased snoring, or suffer from fragmented sleep. The integrity of each nasal subunit plays a role in ensuring open airways and efficient respiration.
Rebuilding the Nose
The concept of nasal subunits is fundamental in reconstructive and cosmetic nasal surgery, guiding surgeons to achieve more natural-looking results. This approach, often termed the “nasal subunit principle,” advocates for addressing each subunit individually rather than treating the nose as a continuous, undifferentiated surface. First described by Burget and Menick in 1985, this principle suggests that if more than 50% of a subunit is lost, the entire subunit should be replaced to better camouflage scars along natural boundaries.
This surgical philosophy helps surgeons place incisions along the borders of these subunits, allowing resulting scars to blend into the natural shadowed valleys and lighted ridges of the nasal surface. For example, when reconstructing a defect on the nasal tip, a surgeon might remove the remaining healthy skin of the tip subunit and replace the entire unit with a new flap of tissue. This technique helps to recreate the natural convex contour of the tip and prevent an unnatural “patchwork” appearance.
The application of this principle is beneficial in cases of trauma, cancer removal, or for aesthetic enhancement. For instance, a forehead flap is a common technique for reconstructing large defects involving the nasal tip, dorsum, or sidewalls, aiming to resurface an entire subunit or multiple subunits. Similarly, nasolabial flaps are often employed for reconstructing alar defects, ensuring the recreation of the alar lobule’s specific contour and maintaining the integrity of the nostril. While the subunit principle offers a strong framework, surgeons also consider other aesthetic factors like skin texture, color, and overall facial symmetry to achieve optimal outcomes.