The Medial Horn and Capsulopalpebral Fascia in the Medial Canthus Are Significant Antagonists of the Orbicularis Oculi Muscle for Lacrimal Drainage

PURPOSE: The anatomical relationship indicates that the medial horn of the levator aponeurosis (MH) and the capsulopalpebral fascia (CPF) are the potential candidates for antagonists of the orbicularis oculi muscle (OOM). This study sought to disclose the relationships among the MH, CPF and OOM, and to discuss their roles in the lacrimal drainage system. METHODS: Twelve medial canthuses of 6 cadavers were studied. After peeling eyelid skin from the OOM, we carefully observed the MH, CPF and OOM in the medial canthus. RESULTS: The MH attached to the superior aspect of the medial canthal tendon. The CPF, which attached to the lower tarsal margin, traveled just under Horner's muscle in the medial canthus and dispersed from a lateral aspect of the lacrimal sac to the posterior lacrimal crest. CONCLUSIONS: As the movement of a muscle can be determined by its origin and insertion, the MH and the CPF are considered to be the antagonists of the OOM, and as such must be taken into consideration for an understanding of the lacrimal drainage system.