Virginia Research Day 2025

Medical Student Research Biomedical

01 Analyzing the Facial Nerve at Zuker’s Point Using Geometric Morphometrics: A Cadaveric Study

Priyanka Shah; Yash Desai; Prutha Patel; Brandon Raquet; Jonathan Millard; Aaron Beger Corresponding author: pshah@vcom.edu

Edward Via College of Osteopathic Medicine - Virginia Campus

The facial nerve, or cranial nerve VII, is made up of five motor branches that are critical for facial movement. They are the marginal mandibular, buccal, zygomatic, temporal, and cervical branches, that course through specific landmarks important for various surgical interventions. This nerve controls muscles responsible for facial expression, and damage to its motor branches can result in functional deficits like facial asymmetry, weakness, or paralysis. Knowledge of the precise course of these branches is essential in procedures such as facial reconstructive surgery, tumor resections, and facial reanimation. Accurate localization of these branches aids surgeons in avoiding nerve injury and preserving facial function. Zuker’s point, a reliable external landmark near key branches of the facial nerve, has shown utility in locating these branches during surgery. However, while studies have used Zuker’s point for this purpose, a thorough understanding of the variation of this nerve's location

is lacking, specifically in three-dimensional space. In this study, dissections were performed on the right side of 24 formalin-fixed donors, using twine, pins, a scalpel, forceps, and surgical scissors. Key landmarks used included the oral commissure, root of the helix, and Zuker’s point. An approximately 0.5-inch square dissection around Zuker’s point was executed to locate the facial nerve, which was marked with a pin upon discovery. A MicroScribe desktop digitizer was employed to capture three dimensional coordinates for four landmarks of interest: the oral commissure (LM1), root of the helix (LM2), Zuker’s point (LM3), and the nearest facial nerve location to Zuker’s point (LM4). Data analysis involved General Procrustes superimposition to align the landmark configurations, followed by principal component analysis (PCA) to assess variation. Results of PCA indicated five principal components, with the first principal component (PC1) accounting for 37.16% of the variance, showing

the greatest variation at LM4. Positive scaling of PC1 showed anteroinferior displacement of LM1 and LM2, which corresponded with posterosuperior displacement of LM3 and LM4. Conversely, negative scaling of PC1 revealed a posterosuperior shift of LM1 and LM2 with anteroinferior displacement of LM3 and LM4. These findings suggest that the location of the facial nerve branch at Zuker’s point may vary anteroinferiorly toward the oral commissure or posterosuperiorly toward the root of the helix. Clinicians should be aware of these variations when planning and performing procedures involving the facial nerve motor branches to avoid complications and ensure optimal outcomes. Recognizing these patterns of variation could enhance surgical precision, reduce nerve injury risk, and improve functional and aesthetic outcomes for patients. This study was reviewed and approved by VCOM IRB (record #2024-039).

Table of Contents

66