BIOANATOMY AND BIOMECHANICS
Together with the eyes the nose forms the centerpiece for initial impression. It has a complex three-dimensional structure, and its skin is nonuniform. With its many distinct forms, the nose is among the most challenging sights for surgical reconstruction, and one of the most rewarding.
The takeoff point of the nose is from the nasion. From this point, the nasal bone extends inferiorly and anteriorly. The majority of the nose is composed of cartilage, fascia, muscle, and skin. The structure of the upper nose rests on the upper lateral alar cartilages. The lower nose is supported by the columella and the lower lateral alar cartilages. Biomechanically, the nasal tissues are relatively inelastic. The upper nose tends to have thin, nonsebaceous skin. The lower nose is more sebaceous. The very tip of the nose and the columella are often thinner and less sebaceous as well. These three zones of nasal skin are identified as type I, II, and III1 (Fig. 7.1). They do not exist in a predictable location and transition variably. Some individuals have thin, mobile type I skin on the majority of the nose, while others—particularly older men—have a thick sebaceous quality of almost all of the nasal skin. In these individuals, reconstruction with local flaps can be particularly challenging due to the inherent visibility of complex surgical scars. The bony/cartilaginous structure of the nose is lined internally by a loose, thin, subcutaneous tissue and mucosa. The external surface of the upper and mid nose is lined by epidermis, dermis, a thin loose superficial fascia, a layer of nasals muscle, and a thicker multilayer inframuscular fascia.
Three types of skin are present on the nose. The type 1 skin of the nasal bridge and upper nose is less sebaceous and more mobile. Type 2 skin is present on the alae and distal nose. It is thicker and sebaceous in nature. Type 3 skin lines the nares, columella, and soft triangle. It is thin, less sebaceous, and relatively immobile
The shape of the nose varies dramatically (Fig. 7.2). Hooked or so-called Roman or Aquiline noses have a very prominent convex shape with a shaper nasal spine. The hawk nose is an accentuated hooked nose, with a very thin side-to-side profile. The Greek or straight nose has no curve to it, proceeding straight from the nasal spine to the tip. The Nubian nose starts thin at the upper bridge and widens and enlarges in thickness toward the wide open nares. This nose type is common in African Americans. The pug nose is a short slightly concave nose, with a flattened tip. The upturned or celestial nose is a long, thin nose with an upwardly projected tip, often with large, prominent lower lateral alar cartilages. Each such nasal subtype presents a different challenge to the ...