Introduction
The nose is a multifarious structure with critical mechanical and functional roles, which by virtue of its position, serves as the central and salient component of the face. Its relationship to surrounding structures is in part responsible for a harmonious, pleasing form as a whole. Functionally, the nose provides an airway and acts to warm, filter, and humidify air passing through it. Noses that deviate from ideal structural proportions – whether subtle variations of normal or more dramatic posttraumatic or neoplastic deformities – have motivated rhinoplasty surgeons since ancient India 800 BCE.
Anatomy
A thorough appreciation and understanding of relevant anatomy is crucial for all surgery. Obviously, recognition of the nuances and subtle variations of nasal anatomy is absolutely vital for execution of a successful rhinoplasty.
Skin
A thorough rhinoplasty evaluation must assess skin type and thickness. The surgeon must anticipate the advantages and limitations afforded by a particular skin type. In general, thin skin is unlikely to camouflage even minor irregularities in the underlying cartilaginous and osseous structures, particularly with grafting. In contrast, thick skin conceals imperfections in the nasal skeleton and may hide surgical flaws or reduce the desired definition intended from alteration of underlying cartilage and bone. 1Sebaceous skin can give the tip a bulbous appearance. The skin is thickest at the nasion. More caudally, the remaining upper half of nose tends to have skin that is thinner and more mobile than the lower half. In the tip area, there tend to be more sebaceous glands. However, in the infratip region, the columella and ala again are usually covered with thinner skin.2,3.
Cartilaginous and Bony Support
An understanding of the bony and cartilaginous structural components of the nose should be complemented by correlation with landmarks of the surface anatomy (Fig. 68.1). Caudal to the glabellar protrusion, the deepest point of the surface of the nose is referred to as the radix. The root of the nose, just caudal to the nasofrontal suture line, is referred to as the nasion, minor adjustments of which can change the overall character of the nose. The rhinion describes the position along the dorsum where the nasal bones articulate with the upper lateral cartilages and the pronasale refers to the region extending from the supratip break, including the tip and infratip lobule, to the anterior-most aspect of the columella. The tip-defining points are the anterior-most points of the nose corresponding to the intermediate crura of the lower lateral cartilages.
Nasal Bones
The bony vault is pyramidal in shape and comprises the paired nasal bones that articulate with the frontal bone superiorly and the ascending maxillary processes laterally. The bony pyramid is narrowest at the level of the intercanthal line and widens inferiorly. 2The nasal bones are thickest cephalically and become thinner caudally. 2,4The nasal bones are supported superiorly at the nasofrontal suture line, laterally at their articulation with the ascending process of the maxilla, and dorsally at their fusion with the perpendicular plate of the ethmoid. The junction between the upper third and lower two-thirds of the nose where the cartilaginous septum meets the nasal bones is referred to as the “keystone area,” as this area is essential for structural support, and stabilizing the nasal dorsum for height and projection.