Mastering surgical anatomy is crucial for the dermatologic surgeon, not only to obtain the best cosmetic outcome but also to avoid complications related to injury of underlying anatomic structures. Since a significant number of dermatologic surgeries are performed on the head and neck, the dermatologic surgeon ought to have full knowledge of the facial nerve and its branches, blood supply, sensory nerves, underlying musculature, and specialized structures such as the parotid duct. With a full understanding of the superficial anatomy of this complex region, the physician will have the confidence to perform a wide range of superficial surgical procedures while keeping possible risks and complications in mind.
The external nose is shaped like a pear or pyramid with several key divisions: dorsum, tip, ala, and lateral sidewalls. The dorsum of the nose extends from the tip, the lowermost aspect of the nose, to the nasal root. In contrast to the dorsum of the nose where the skin is quite mobile, the skin overlying the tip of the nose is adherent to the underlying fibrous tissue and cartilage. The nasal bridge is the portion of the nose overlying the nasal bones. The lateral sides of the nose encompass the area from the nasal dorsum to the cheeks. The nasofacial sulcus, or margin of the nose, is the transition from the lateral aspects of the nose to the cheeks.1
The ala, a distinct cosmetic subunit, is demarcated from the lateral sidewalls of the nose by the alar crease and separated from the lip by the nasolabial crease. The root of the nose is the region of attachment of the nose to the glabella. The nares are the openings into the anterior nasal vestibules. They are divided by the nasal septum medially and bounded by the nasal alae laterally. The columella is the freely movable portion of the nasal septum (Fig. 1-1).2
Cutaneous anatomy of the nose.
The skeleton of the nose includes both bone and cartilage. The two nasal bones lie adjacent to the maxilla laterally and the frontal bone superiorly. There are also five major cartilages of the nose which provide the remainder of the nasal framework: two lateral cartilages, two greater alar cartilages, and the single septal cartilage. In the midline, the septal cartilage joins each of the lateral cartilages. The lateral aspect of the lateral cartilage articulates with the frontal process of the maxilla whereas the superior aspect of the lateral nasal cartilage articulates with the inferior aspect of the nasal bone. The greater alar cartilages are C-shaped. Each of the medial crura joins at the midline with the septal cartilage to form the nasal septum. The lateral crura articulate with the inferior aspects of the lateral nasal cartilages.1