Anatomical Study of the Zygomaticotemporal Branch Inside the Orbit

The location of the opening of the zygomaticotemporal branch (ZTb) of the zygomatic nerve inside the orbit (ZTF_IN) has significant surgical implications. This study was conducted to locate the ZTF_IN and investigate the variations of the ZTb inside the orbit. A total of 20 sides from 10 fresh frozen cadaveric Caucasian heads were used in this study. The vertical distance between the inferior margin of the orbit and ZTF_IN (V-ZTF_IN), the horizontal distance between the lateral margin of the orbit and ZTF_IN (H-ZTF_IN), and the diameter of the ZTF_IN (D-ZTF_IN) were measured. The patterns of the ZTb inside the orbit were classified into five different groups: both ZTb and LN innervating the lacrimal gland independently (Group A), both ZTb and LN innervating the lacrimal gland with a communicating branch (Group B), ZTb joining the LN without a branch to the lacrimal gland (Group C), the ZTb going outside the orbit through ZTF_IN without a branch to the lacrimal gland nor LN (Group D), and absence of the ZTb (Group E). The D-ZTF_IN V-ZTF_IN H-ZTF_IN ranged from 0.2 to 1.1 mm, 6.6 to 21.5 mm, 2.0 to 11.3 mm, respectively. The number of sides in Groups A, B, C, D, and E were 13 sides (65%), three sides (15%), none (0%), two sides (10%), and two sides (10%), respectively. Such anatomical knowledge might reduce complications following surgery in and around the ZTb.