Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!


(dor′nās) Short for deoxyribonuclease.


(dōr′săd) [dorso- + -ad] Toward the back.


(dor′săl) [L. dorsalis, fr. L. dorsum, back] 1. Pert. to the dorsum (back). In bipeds, posterior is more appropriate than dorsal. 2. Lying on the back with the face upward; supine. 3. Toward the back of an organism.

dorsal hump

An enlargement or lump on the nasal bridge. In rhinoplasty a rasp is used to reduce it.


(dor-sā′lĭs) [L. dorsalis, fr. L. dorsum, back] Pert. to the back; dorsal.

dorsiflexion, dorsiflection

(dor″sĭ-flek′shŏn) [dorso- + flexion] Movement of a part, i.e., a hand, a foot, at a joint, bending that part toward the dorsum (the posterior aspect) of the body. Dorsiflexion of the foot is a movement backward and upward: the foot moves toward its top (dorsum); the opposite of plantar flexion. Dorsiflexion of the toes is a movement of the toes upward and away from the sole of the foot. Dorsiflexion of the hand is a backward extension of the hand bending at the wrist; the opposite of palmar flexion, or volar flexion of the wrist. SEE: palmar flexion; plantar flexion; volar flexion.

dorso-, dorsi-, dors-

Prefixes meaning the back or dorsum.


(dor″sō-lat′ĕr-ăl) [dorso- + lateral] In anatomy, pert. to the back and side.


(dor″sō-lŭm′băr, dor″sō-lŭm′bar″) [dorso- + lumbar] In anatomy, pert. to the lower thoracic and upper lumbar (loin) area of the back.


(dor″sō-plant′ăr, dor″sō-plan′tar″) [dorso- + plantar] In anatomy, from the top of the foot to the bottom.


(dor″sō-ven′trăl) [dorsoventral] In anatomy, pert. to the back and frontal surfaces of the body.


(dor′sŭm, dor′să) pl. dorsa [L. dorsum, the back, ridge] 1. In anatomy, the back or posterior surface of a part. 2. On the foot, the top of the foot.


(dō′sij) [Gr. dosis, a giving] 1. A specified or prescribed quantity of any therapeutic intervention. 2. The determination of the prescribed quantity of a therapeutic agent.

sublethal d. Sublethal dose.


(dōs) [Gr. dōsis, a giving] 1. The amount of medicine or radiation administered. 2. The measurable exposure to an agent, e.g., to a poison, a quantity of radiation, or an irritant in the environment.

absorbed d. 1. The quantity of ionizing ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.