An Overview on Classifications of Hepatic Artery Variants

Abstract

Background: Hepatic arterial anatomy exhibits considerable anatomical variability, making accurate recognition and classification of hepatic artery variants essential for radiological assessment and surgical planning. Several classification systems have been developed to describe these variations. Michels’ classification, based on cadaveric dissections, describes ten types of hepatic arterial anatomy, whereas Hiatt’s classification provides a simplified system of six categories derived from surgical cases. These systems remain fundamental for understanding hepatic arterial variability and its surgical relevance. More recently, the CRL classification was introduced to describe the origins of the common hepatic artery, right hepatic artery, and left hepatic artery, including replaced and accessory vessels, and to cover a wider range of arterial variants. However, some rare patterns cannot be categorized adequately by the CRL system. Consequently, the extended CRL (ex-CRL) classification was developed to systematically categorize uncommon hepatic arterial origins and complex variants that were previously described mainly in individual case reports.