Sihler staining study of anastomosis between the facial and trigeminal nerves in the ocular area and its clinical implications

Introduction: The trigeminal nerve (CN V) supplies mostly sensory innervation to the face, and the facial nerve (CN VII) conveys primarily motor fibers. The aim of this study was to elucidate their distributions and anastomoses. Methods: Fourteen specimens of hemisectioned faces were gathered from human cadavers and stained with Sihler staining. Results: The temporal (Tbr), zygomatic (Zbr), and buccal (Bbr) branches of CN VII formed trigeminofacial anastomoses in the ocular area. Communications were observed between the supraorbital nerve and the Tbr (85.7%), the infraorbital nerve and the Bbr (100%) and Zbr (28.6%), and the zygomaticofacial nerve and the Zbr (41.7%). Anastomoses were formed between the supratrochlear nerve and the Tbr (57.1%) and Bbr (50%), and the infratrochlear nerve and the Bbr (85.7%). Conclusions: Motor and sensory axons to the face contribute to trigeminofacial anastomoses, which may play key roles in subtle movements of muscles of facial expression.