Definition of "dorsum" [dor•sum]

• The back. (noun)
• The upper, outer surface of an organ, appendage, or part: the dorsum of the foot. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The external surface (Fig. 235), known as the dorsum ilii, is directed backward and lateralward behind, and downward and lateralward in front."
• "The new species is distinguished from all congeners by having a melanistic color pattern, with head and dorsum of the body mostly dark-brown to black; absence of postocular stripe; venter grayish-brown, with dark rounded blotches outlining two lateral stripes which become gradually paler towards the posterior region of the belly, disappearing after midbody."
• "Serpentine veins rise across the dorsum of her hand, swollen with the back pressure of blood."