The term medial zone of the hypothalamus refers to one of three zones of the hypothalamus when it is subdivided by planes parallel to the midline. The others are the periventricular zone of the hypothalamus and the lateral zone of the hypothalamus. The medial zone lies between the other two. It includes the paraventricular nucleus of the hypothalamus, the supraoptic nucleus, the medial preoptic nucleus, the anterior nucleus of the hypothalamus, the retrochiasmatic area, the ventromedial nucleus of the hypothalamus, the dorsomedial nucleus of the hypothalamus, the supramammillary nucleus, the medial part of the medial mammillary nucleus, the lateral part of the medial mammillary nucleus and the lateral mammillary nucleus ( Saper-1990 ).