The term insular apex (iax) refers to a surgical landmark in the insula (INS) of the human. Identified by dissection it is the most prominent point of the insular cortex. It is a surface feature located at the junction of the anterior short gyrus (ASG) , the posterior short gyrus (PSG) and the accessory insular gyrus (AIG) ( Ture-1999 ). It is not described in the macaque ( Martin-2000 Paxinos-2009a ) and not present in the smooth cortex of the rat and mouse ( NeuroNames ).Updated 24 Aug 2024.