Emergence Point of the Zygomaticotemporal Nerve Relative to the Marginal Tubercle of the Zygomatic bone: a Cadaveric Study with Clinical Implications

PURPOSE: The aim of this study is to identify the anatomical location of the emergence point of the zygomaticotemporal nerve (EP) in the lateral orbital margin with reference to the marginal tubercle of zygomatic bone (MT), and to determine whether the MT can serve as a consistent landmark for zygomaticotemporal nerve (ZTN) block procedures. METHODS: Thirty-six hemifaces from 20 cadavers were dissected. The spatial relationships of the EP with the MT and the lateral canthus (LC) were the main outcomes. Facial proportions were recorded as covariates. Cross-sectional relationships of the ZTN with the middle temporal vein (MTV) and the frontal branch of the facial nerve (FN) in fascial planes were also examined. RESULTS: The EP was consistently identified near the lateral orbital margin, located 4.5±1.6 mm superior to the MT and 17.6±2.7 mm lateral and 9.5±2.9 mm superior to the LC. The vertical distance to the MTV was 7.3±2.3 mm, with both structures positioned within the same fascial plane. In contrast, the FN coursed through a more-superficial layer. Correlation analyses indicated that while the facial proportions affected the absolute location of the ZTN, they did not alter its spatial relationship to the MT. CONCLUSION: The MT serves as a consistent palpable landmark for locating the EP, facilitating more-accurate regional nerve blocks for anesthesia, postoperative pain control, and neuralgia treatment. When the MT is not palpable, the LC can serve as an alternative landmark. Understanding their spatial relationships with surrounding structures-including the MTV and FN-may help prevent vascular injury and inadvertent FN blockade.Levels of Evidence: Basic science and clinical study.