Abstract
The luminal surface of the human endolymphatic sac was observed by scanning electron microscope. The morphological findings of endolymphatic sac can be divided into three portions; proximal, intermediate (rugose), and distal portion. The intermediate portion is composed of three types of cells : light cell, dark, and duct cells. This portion seems to be the most active part from the point of morphological structures. The proximal portion was covered with hexagonal or pentagonal flat cells. The surface of the distal portion was also covered with flat cells, but among the flat cells, groups of dome like cells were seen here and there. These dome like cells were similar to those seen in the inter mediate portion.
The dome-like cells with long microvilli seem to be light cells and those with less microvilli, dark cells.
