The distribution of temporal branches of facial nerve at the upper part of orbicularis oculi muscle and its clinical significance

Objective:To study the distribution of temporal branches of facial nerve at the upper part of orbicularis oculi muscle (OOM). Methods: 18 cadaveric hemifaces were dissected. Temporal branches of facial nerve passing from the parotid gland to the orbicularis oculi muscle were observed. The highest and lowest branches coursing into the OOM were measured at three different planes through the lateral canthus, midpalpebral fissure, and medial canthus, respectively. Results: The highest level of those twigs that entered OOM on coordinate axis with lateral canthus as point was about (+2.58±0.32cm,+2.89±0.32cm), and the lowest (0 cm, +2.81±0.32 cm). The highest level of those twigs on the Y-axis with the point of lateral canthus, midpalpebral fissure, and medial canthus was about (3.53±0.39 )cm,( 3.87±0.38)cm, and (3.22±0.39) cm respectively, and the lowest (1.14±0.15 )cm, (1.26±0.10 )cm, and (1.02±0.14 )cm respectively. Temporal branches of facial nerve coursed horizontally along the fibers of OOM and connected with each other. The region below the curve formed by lower three points had no innervation from branches of facial nerve. Conclusions:The injury for temporal branches of facial nerve is evitable during the separating procedure in the fat layer, as well facial nerve during the process of incising fibers of OOM in the region having no facial nerve innervation.