External carotid A.

Fig. 6.2 (continued)

Summary: Midface

•Knowledge of the boundaries of the cosmetic subunits is especially important in planning reconstruction on the midface.

•Vasculature of the nose contains an essential anastomotic site between the external and internal carotid systems.

•Branches of the facial nerve (CN VII) provide motor innervations to the midface, while the maxillary and mandibular divisions of the trigeminal nerve (CN V) provide sensory input.

6.3Midface

6.3.1Nasal Subunit

The nasal subunit is generally subdivided into a number of cosmetic subunits [2]. These are the nasal

Internal carotid A.

sidewall, nasal dorsum, tip, alae, soft triangles, and the columella (Fig. 6.4). To achieve the best cosmetic outcome, incision lines during nasal reconstruction should be placed at the borders of these cosmetic units. The nasal cartilaginous structures, consisting of the lateral nasal and the lower lateral cartilage, are the key to maintaining the integrity of nasal morphology (Fig. 6.5). Infiltrative tumors may involve the lower lateral nasal cartilage, requiring its excision. Failure to repair or replace the cartilage in this situation may result in the loss of alar support, leading to collapse of the nasal ala and lack of airflow into the nose.

6.3.1.1 Vasculature

The vasculature of the nose is derived from both the internal and external carotid arteries [3]. In fact, arteries supplying the nasal area make up one of the key anastomosing sites between the internal and external carotid arteries. The dorsal nasal and external nasal branches of the ophthalmic artery, which branches off

Pre-auricular nodes

Parotid nodes

Post-auricular nodes

Occipital nodes

Spinal accessory chain

Transverse cervical chain

Fig. 6.3 Lymphatic drainage of the head and neck

Sidewall

Dorsum

Soft triangle

Supratip

Tip

Ala

Infratip

Columella

Facial nodes:

Infraorbital node

Malar node

Buccinator node

Mandibular nodes

Submental nodes

Submandibular nodes

Superficial cervical node

Internal jugular chain

Lobule

Alar margin