The nerve supply of the nasal skin comes from the ophthalmic and maxillary divisions of the trigeminal nerve. The bridge of the nose is supplied by the infratrochlear nerve (a branch of the naso-ciliary nerve). The nasal tip is supplied by the external nasal nerve which is the terminal branch of the anterior ethmoidal nerve. The side of the nose and the ala are supplied by the nasal branches of the infraorbital nerve. The superior part of the columella is adjacent to the nasal tip and, likewise, is supplied by the external nasal nerve. Inferiorly, the nerve supply of the columellar skin comes from the labial branches of the infraorbital nerve.
The open approach in rhinoplasty has been advocated by several authors mainly because of the increased exposure it affords when compared to the closed technique.
Altered sensibility following open rhinoplasty occurs in the early postoperative period in the area of skin supplied by the external nasal nerve (nasal tip and adjacent upper columella). The nerve is probably injured during the subcutaneous dissection as the nerve passes between the nasal bone and the upper lateral cartilage to supply the skin. Furthermore, the nerve will always be divided if in an external rhinoplasty the cranial part of the lateral crus is divided. It is important to realise that injury to the external nasal nerve could also occur during inter-cartilaginous and cartilaginous splitting incisions of the endonasal rhinoplasty.
There is significant recovery of sensibility in the skin supplied by the external nasal nerve by 1 year after surgery. This may either be due to recovery of the external nasal nerve itself, or collateral sprouting from the nerves supplying the adjacent areas of skin.