Caruncles

Caruncle, plural caruncles, is a term used in biology to describe a small fleshy outgrowth or nodular structure found in various organs and tissues. The word comes from the Latin caruncula, meaning a little piece of flesh. Because caruncles occur in different contexts, their form and function can vary widely between species and organ systems.

In human and veterinary anatomy, the lacrimal caruncle is the small, pinkish nodule at the inner corner of the eye. It contains sebaceous and sweat glands and is part of the ocular surface anatomy. The caruncle can be involved in clinical conditions such as inflammation (carunculitis) or rare growths, and its appearance can be a minor diagnostic feature in eye examinations.

In placental biology, caruncles are maternal structures found in the uterine lining of many ruminant mammals, including cattle, sheep, and goats. These caruncles form the maternal portion of the placentome, pairing with fetal cotyledons to create the functional interface for nutrient and gas exchange between mother and fetus. Caruncles are typically highly vascular and undergo changes during pregnancy; abnormalities can affect placental function and reproductive outcomes.

In birds and some other animals, caruncles refer to fleshy nodules on the head or neck, often noticeable as part of display coloration or thermoregulation. The exact pattern and prominence of these caruncles vary by species and sex.

In botany, caruncle denotes a small outgrowth on certain seeds or fruits. Such seed caruncles may be glandular or mucilaginous and can influence dispersal or moisture interactions in some species.