Anatomical Comparative Study of the External Nasal Nerve in Caucasian and Asian: Application for Minimizing Nerve Damage in Rhinoplasty

Chen Y, Carr CB.

PubMed 34498142 Publisher (DOI)Free full text (PMC)

What this paper says

Dissecting 20 Caucasian cadavers, the nerve supplying sensation to the nasal tip emerged an average 8.31 mm from the midline, significantly further out and across a wider range than reported in Asian anatomy.

Overview

Numbness of the nasal tip is the main symptom of injury to the external nasal nerve, particularly after rhinoplasty, and it reduces satisfaction with the operation. All previous anatomical research on this nerve came from Asia. This study set out to fill that gap for Caucasian anatomy and compare the two.

Sections of note

Cadaveric study on 20 Caucasian cadavers embalmed using the Thiel method; the journal assigns level of evidence III.
After exposing the nerves, the distance from the nerve's exit point to the nasal midline was measured.
Nerves were classified into types based on their branching pattern.
The plane in which the nerve runs was the same as recorded in Asian anatomy.
The distance ranged from 5.08 to 11.94 mm, mean 8.31 plus or minus 1.85 mm.
That distance differed significantly from the Asian population, P less than 0.01, being larger on average with a wider distribution of exit points.
Thirty five of 40 cases matched previously reported types I, II and III.
Five new variants were found, classified as subtypes and a new type IV.
In two thirds of type II cases the branching point was closer to the origin than in the Asian population.

What it means for a patient

Tip numbness after rhinoplasty is caused by injury to a specific nerve whose position varies between individuals.
In Caucasian anatomy the nerve emerges further from the midline and across a wider range, which the authors say makes it more vulnerable.
Twenty cadavers is a small sample and the comparison was against published Asian data rather than a matched group.
This is anatomy. No patients, surgery or numbness outcomes are reported.

Why this paper matters

Nasal tip numbness is common after rhinoplasty and is usually accepted as unavoidable rather than anatomically explained. This study maps the nerve in a population where it had not been described. Whether knowing its position reduces numbness in practice is untested.

Terms

External nasal nerve: the nerve carrying sensation to the skin of the nasal tip.
Cadaveric dissection: study of anatomy in preserved human bodies.
Thiel method: an embalming technique that keeps tissue soft and lifelike.
Nasal midline: the vertical centre line of the nose, used as a measurement reference.
Bifurcation: the point where a nerve divides into two branches.

Summary written by rhinoplasty.cc from the abstract, 2026-09-09; not medical advice. The authors' own abstract follows.

Abstract

Background: The numbness of the nasal tip is the main symptom of the external nasal nerve injury, especially after rhinoplasty. This postoperative syndrome can reduce the patient's satisfaction with the operation. Having a better understanding of the anatomical structure and intraoperative protection can effectively avoid nerve injury. At present, the anatomical research on this nerve is all from Asia. This study aims to fill the gap in the anatomical study of this nerve in Caucasians and provides comparative results with Asians.

Material And Methods: A total of 20 Caucasian cadavers were embalmed using the Thiel method. On dissection, after complete exposure of the external nasal nerves, the distance between the exit point of the external nasal nerve and the nasal midline was measured, and the morphology of the nerves was compared with the Asian data. The nerves were classified into types based on their branching pattern.

Results: The nerve plane was the same as the Asian record. The distance ranged from 5.08 to 11.94 mm (mean, 8.31 ± 1.85 mm). This distance has statistical significant difference compared with the Asian population (P < 0.01). The average distance is larger, and the distribution range of the exit point is wider. On classification, 35 of 40 cases had the same type results as those previously reported, with the primary types I, II and III. Five new varieties were found which are classified as subtypes of the primary types and a new type IV. Furthermore, the bifurcation position in two-thirds of the type II cases and variations is proximal to that seen in the Asian population.

Conclusions: The anatomical structure of the external nasal nerve in Caucasians and Asians has obvious differences. This nerve in Caucasians is more likely to be damaged during rhinoplasty than Asians. Except the primary types, the classification of the external nasal nerve also includes subtypes and type IV.

Level Of Evidence Iii: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Abstract as indexed by PubMed; the article is open access (PubMed Central).