The medial segment is also called the quadrate lobe.

These are the caudate lobe (the more superior) and the quadrate lobe (the more inferior).

It is demarcated anteriorly by the quadrate lobe of the liver, the stomach, lesser omentum and gastrocolic ligament.

The upper group typically arises from the posterior aspect of the liver, are three in number, and drain the quadrate lobe and left lobe.

These separate the right lobe in two smaller lobes on its left posterior part: the quadrate lobe and the caudate lobe.

It joins nearly at right angles with the left sagittal fossa, and separates the quadrate lobe in front from the caudate lobe and process behind.

It should not be confused with the anatomic lobes of the liver (caudate lobe, quadrate lobe, left lobe, and right lobe), or any of the functional lobe classification systems.

Traditional gross anatomy divided the liver into two lobes (left and right), if viewed from the parietal surface; but if observed on the visceral surface it is divided into four lobes with the addition of the caudate and quadrate lobe.

But worse than that for our purposes was his case-book showing long-drawn-out histories of general bilious indisposition, melancholy, taedium vitae sometimes reaching mere despair, extreme irascibility: all this with no known agent, though autopsy showed an enlarged quadrate lobe studded with yellow nodules the size of a pea.

'It is situated on the right side of the body closely in contact with the inferior surface of the liver,along the right edge of the quadrate lobe in a shallow fossa extending from the right edge of the porta hepatis to the inferior lobe of the liver'