Auriculotemporal nerve morphology revisited: a novel classification based on root pattern and arterial topography

The auriculotemporal nerve (ATN), carrying both sensory and parasympathetic fibers, is a branch of the mandibular nerve (MN) and courses through the anatomically complex infratemporal fossa (ITF). Along its path, it maintains close proximity to the maxillary artery (MA) and middle meningeal artery (MMA). This study aimed to investigate the morphometry, formation patterns, and vascular relationships of the ATN in both adult cadavers and fetuses. Bilateral ITF dissections were performed on 15 adult cadavers (mean age: 76.07 ± 14.1 years) and 15 fetuses (mean gestational age: 23.87 ± 3.40 weeks). The number of roots forming the ATN, their morphometry, configurations, and vascular relationships were documented. A classification system was developed based on root number, fusion patterns, and spatial relation to the MA and MMA. Both adult and fetal specimens demonstrated various root and connection patterns. Up to five roots were observed in adults and up to four in fetuses. In both groups, the two-root configuration was the most common (60%). The first root passed lateral to the MMA in 87% of adults and 90% of fetuses, while the second root was medial in 81% and 79%, respectively. Understanding the anatomical variability of the ATN is essential for safe surgical navigation within the ITF. Dissection-based studies that illuminate such variations provide valuable guidance for clinical procedures involving this region.