, gen. and pl. insulae [TA] (1) [TA], An oval region of the cerebral cortex overlying the extreme capsule, lateral to the lenticular nucleus, buried in the depth of the fissura lateralis cerebri (sylvian fissure), separated from the adjacent frontal, parietal, and temporal opercula by the circular sulcus of insula. SYN: insular area, insular cortex, island of Reil. (2) SYN: island. (3) Any circumscribed body or patch on the skin. [L. island]