Male Left Liver Medial Division, Inferior View

Description

Oriented from the inferior (visceral) surface, the medial division of the left hepatic lobe is centered on the quadrate segment (Couinaud segment IV), positioned anterior to the porta hepatis and immediately adjacent to the gallbladder fossa on its right. Medially, segment IV approaches the fissure for the ligamentum teres, while posteriorly it transitions toward the region of the caudate lobe across the transverse fissure. The inferior margin of the liver forms the anterior border of this field. Segmental anatomy, not just lobar anatomy. Segment IV is a frequent point of reference in hepatobiliary surgery because it sits between the left lateral segments (II and III) and the right anterior sector (V and VIII), so its portal pedicles and venous drainage influence how surgeons plan a left hepatectomy, extended left resection, or segment IVb wedge. That relationship becomes practical when treating colorectal liver metastases or hepatocellular carcinoma near the gallbladder fossa, where achieving a clear margin can mean the difference between a limited resection and a more extensive anatomical segmentectomy. An inferior view also aligns with what is encountered during laparoscopy, when the visceral surface and porta hepatis define the working anatomy. Use this illustration to support teaching of Couinaud segmentation in gross anatomy, surgical anatomy, and radiology correlation modules, and to clarify operative reports or textbook figures describing quadrate lobe resections, cholecystectomy-adjacent lesions, or hilar dissection landmarks. It also fits hepatobiliary oncology publications that need a clean depiction of segment IV boundaries from the visceral aspect. Anatomical accuracy verified by SciePro's Medical Advisory Board.