In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.
[1] When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17.
These numbers correspond to the number of dorsal scales around the body at a head's length behind the head, at midbody and at a head's length before the vent.
[1] Dorsal scale are easiest to count diagonally, starting with the paraventral scale row.
[1] In doing so, it is often noted that certain scale rows are raised, keeled or smooth as opposed to the others.