The radix

The nasion refers to the deepest point of the nasofrontal angle (ideally 134 degrees) and typically lies 4–5 mm cephalad to a horizontal plane drawn through the lateral canthus. This usually corresponds to a point between the lash line and the upper eyelid crease. The ideal nasion point lies about 4–6 mm posterior to the vertical glabellar tangent and about 10–11 mm anterior to the vertical corneal tangent. Establishing the correct nasion point is critical, since it will determine the nasal start point and subsequently help to establish nasal length. The radix is not a point, but instead is an area centered at the nasion that extends from the intercanthal plane to the nasion point and then for a comparable distance cephalad. The most cephalad aspect of the radix roughly corresponds to the level of the naso-frontal suture line.

The dorsum

The three most important factors relating to the dorsum are height, straightness and integration. The osseocartilaginous vault that comprises the dorsum is formed embryologically by cephalic ossification of the cartilaginous nasal placode. This explains the great overlap of the nasal bones over the upper lateral cartilages, which measures 11 mm in the midline and 4 mm out laterally. Thus the bone and cartilage do not simply join together in a seam, but rather overlap in a bayonet-type configuration. The inclination of the lateral walls from the maxilla is roughly 57 degrees. The cartilaginous vault is a single anatomical entity; not a septum with two juxtaposed upper lateral cartilages. The overlying soft tissue envelope is thickest at the radix area, where the procerus muscle rises from the bony vault to insert into the forehead. The envelope is thinnest over the rhinion. On anterior view, the parallel dorsal lines are a continuation of the supraorbital ridge lines which narrow at the radix and then run down to the tip defining points. The ideal width of the lines frequently corresponds to the width of the tip defining points and is 6–8 mm in females; 8–10 mm in males. The base bony width is the widest point of the nose at the level of the maxilla. The ideal final aesthetic line is concave for females and straight for males.

The tip

The usual concerns in the tip are volume, definition, width, rotation and projection. In secondary cases, distortion, deformity and deficiency must also be considered. The tip is composed of the paired lower lateral (alar) cartilages, each of which is composed of three crura; medial, middle and lateral (Fig. 39.1). The medial crus is comprised of the lower footplate segment and the superior columellar segment. The columellar–lobular junction marks the transition from the nasal base to the tip lobule and usually corresponds to the nostril apex (1–2 mm). The middle crus extends from the columellar–lobular junction to the lateral crus. The middle crus consists of the medial lobular segment and the more lateral domal segment. It is the domal segment that normally contains both the medial genu (the transition with the infralobular segment) and the lateral genu (the transition to the lateral crus). It is these two genu that bracket, and therefore create the anatomy of the “domal notch”. The lateral crura are made up of the lateral crus and accessory cartilages. The lateral crus is the main component of the nasal lobule. Medially, the lateral crus–domal junction line determines tip definition. Cephalically, the lateral crus has a scroll formation adjacent to the upper lateral cartilages. Caudally, the inferior border of the lateral crus diverges away from the nostril rim. Laterally, the crus passes away from the nostril rim and tapers in size. Configuration, axis of orientation and axis of curvature of the lateral crus all affect its aesthetic fabric.

Fig. 39.1 A&B, Anatomy of the tip.

With kind permission from Springer Science & Business Media: Daniel R. Rhinoplasty: An atlas of Surgical Techniques. 2002.

The nasal base

The nasal base is not a distinct anatomical entity; its aesthetic is frequently impacted by adjacent tip structures. The nasal base is subdivided into eight separate components (Fig. 39.2). The columella base consists of soft tissue, depressor septi nasalis muscle centrally, the nasalis muscles laterally and the medial crural footplates. The transverse width of the columella base is related to the separation of the footplates and the quantity of intervening soft tissue. The central columellar pillar is created by medial crura apposition; its length determined by the medial crura termination at the columellar lobular junction. The infralobular triangle and soft triangle are the capstone of the basilar pyramid and are determined by the configuration of the middle crura. The soft triangle is a reflection of the width of the domal notch and is comprised of a web of opposed skin and vestibular mucosa, which is devoid of cartilage. The lateral wall reflects the support and proximity of the lateral crura to the alar rim. The alar base is composed of subcutaneous tissue and muscle and serves as an external baffle for the nose, which determines the amount of alar flare and width. The nostril sill varies widely on its vestibular and cutaneous surfaces, and is intimately affected by the configuration of the adjacent alar base. The nostril is the central void that is determined only by its surrounding structures and is highly variable between individuals.

Fig. 39.2 A–D, Nasal base components.

With kind permission from Springer Science & Business Media: Daniel R. Rhinoplasty: An atlas of Surgical Techniques. 2002.

Assessing the septum and turbinates

The importance of accurate evaluation of the septum in the secondary nose cannot be overstated. Septal surgery can consist of septoplasty (resection and relocation) for treating deviations, or septal harvest for graft materials. While it is crucial to establish the dorsal line before harvesting the septum, in secondary noses the septum frequently has been partially (and possibly maximally) harvested during the prior operation(s). Assessing the septum early is essential for three reasons. First, it clarifies any questions about the presence or absence of support. Second, it defines the existence of persistent septal deviations or prior surgical misadventures. Third, it allows the surgeon to establish the availability of septal cartilage to be harvested for graft material at the outset.

Following Betadine preparation and subperichondrial injection with 1% Xylocaine with epinephrine, a right vestibular hemi-transfixion incision is performed and the caudal septum is identified. Sharp dissection with a Converse–Daniel scissor is performed down to the perichondrium. In order to facilitate the dissection and guarantee that you are in fact in the subperichondrial plane, cross-hatches are made on the caudal septum and then a Cottle elevator is used to elevate the mucoperichondrium and reveal the Robin’s-egg blue color beneath. The elevator is inserted dorsally parallel to the septum and a vertical sweep is done back and over the perpendicular plate of the ethmoid, and then down onto the vomer (Fig. 39.3). The inferior portion is then dissected from back to front coming from the posterior vomer forward, allowing easier separation of the fused perichondrial/periosteal fibers. If the septum has been previously harvested, this dissection is done only over the dorsal aspect of the L-strut. One must be careful separating the mucosa–mucosa adherence if the septal body has been previously harvested. If still present, cartilage harvest is accomplished with a #15 blade, septal scissors and a Cottle elevator taking great care to preserve at least a 10 mm wide L-shaped strut. If a dynamic septal collapse is present, then septal replacement grafts must be considered.

Fig. 39.3 A–D, Assessment of the septum.

With kind permission from Springer Science & Business Media: Daniel R. Rhinoplasty: An atlas of Surgical Techniques. 2002.

Once all septal surgery has been completed, attention can be turned to the turbinates. Although turbinate hypertrophy is a common additional cause of airflow restriction, caution must be exercised with turbinate resection. Most turbinate enlargement can be adequately treated with either out-fracture or judicial partial submucosal resection.

Opening and assessing the skin envelope