a small, inconstant semilunar groove on the cortical convexity near the occipital pole, marking the anterior border of the striate cortex (Brodman area 17) and considered homologous with the major sulcus of the same name that is a more constant feature of the cerebral cortex in monkeys and apes. SYN: lunate fissure [TA], sulcus lunatus [TA], simian fissure.
