Muscle fibre types of human orbicularis oculi muscle

초록

The orbicularis oculi muscle (OOM) is a complex facial muscle involved in eyelid closure. The OOM consists of palpebral, pre-septal, pre-tarsal, and ciliary (muscle of Riolan) parts. It is expected that each part of the OOM has different muscle types because the form follows function. The aim of this study was to elucidate the muscle type of the pre-septal, pre-tarsal, and ciliary parts of the orbicularis oculi muscle (OOM) in humans using immunostaining.Our result showed the eyelid has a higher proportion of fast muscle fibers than the mouth (pars peripheralis, 73% fast fibers; and pars marginalis, 66% fast fibers). Thus, closing of the eyelids is faster than closing of the mouth; however, the duration or power associated with closing of the mouth is stronger than closing of the eyelids.