Dorsum (anatomy)

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For the portion of the brain sometimes called the dorsal, see Medial longitudinal fasciculus.
Dorsal view of a rove beetle

In anatomy, the dorsum is the upper side of animals that typically run, fly, swim or crawl 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.

In lepidoptera (moths and butterflies), the dorsum also refers to the trailing edge of the wing (the leading edge is called the costa).

The term "dorsum" is used for the upper surface of the body of nudibranch sea slugs.

Human anatomy[edit]

In general, dorsal in terms of human anatomy is generally synonymous with posterior. For example, the heart is dorsal to the breastbone while the spinal column is dorsal to the heart.[1]

Some exceptions exist, however due to varied orientation on quadrupedal mammals, where the term is more appropriately used. Examples of these include the back-side of the hand, the top-side of the foot and the upper surface of the tongue are referred to by the term dorsum.

In neurobiology, nerve rootlets stemming from the spinal cord form dorsal (sensory) and ventral (motor) roots before these unite to form the spinal nerve.

See also[edit]


  1. ^ "Essentials of Human Anatomy and Physiology", Elaine N. Marieb, Tenth Edition