Dorsum (biology)

In anatomy, the dorsum is the upper side of animals that typically run, fly or swim in a horizontal position, and the back side of animals (like humans) that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow off that side of an animal. The opposite side of the animal is described with the terms ventrum and ventral.
See more at Wikipedia.org...