(or-bik'u-lus) plural.orbiculi [L., little circle]
Muscle surrounding an orifice; a sphincter muscle.

orbiculus ciliaris

The portion of the ciliary body consisting of a bandlike zone lying directly anterior to the ora serrata. Synonym: ciliary ring

orbiculus oris

The circular muscle surrounding the mouth. It is a muscle of facial expression, innervated by the facial nerve.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
`ambitus, circulus, orbiculus', commenting, `in ima vesicae parte sire cervice, orbiculus quidam, sire orbicularis est ambiens quidam musculus a natura formata est'.)