What is a term which refers to the areas in the back or rear, with the same scope as the word "frontal"? The satirical/humorous term backal exists, but is not really a word (or appropriate to use in writing).
The term that is used most often is dorsal. When used of a human being, or an upright animal, it refers to the back, or to that which pertains to the back. When used of a quadruped, it refers to the upper side, which usually corresponds to the back of an upright animal. While frontal is used of a human being or an upright animal, the corresponding term for quadrupeds is ventral. Dorsal and ventral are also used of inanimate objects that are oriented horizontally, such as submarines.