The medial border of the kidney is concave in the center and convex toward either extremity; it is directed forward and a little downward. Its central part presents a deep longitudinal fissure, bounded by prominent overhanging anterior and posterior lips.
The medial boundary of the kidney has a concave shape in the middle and an outward slope toward both ends; it points forward and slightly downward. Its central region features a deep longitudinal groove, separated by prominent edges on either side.