1. The sinuous, scalloped line in the iris that divides the central pupillary zone from the peripheral ciliary zone and marks the embryonic site of the atrophied minor vascular circle of the iris. 2. Brittle scales encircling eyelashes in staphylococcal blepharitis. SYN: iris frill.
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col·lar·ette (kol″ər-etґ) 1. a narrow rim of loosened keratin overhanging the periphery of a circumscribed skin lesion, attached to the normal surrounding skin, such as in candidiasis or pityriasis rosea. 2. an irregular jagged line dividing the anterior surface of the iris into two regions, the ciliary zone and the pupillary zone. Called also angular line. 3. in mycology, a ring around the apex of a phialide resulting from rupture during release of the first phialospore.
Collarette separating the ciliary and pupillary zones.
Medical dictionary. 2011.