dorsal

Dorsal is a directional term used in anatomy and biology to describe the back or upper side of an organism or body part. It comes from the Latin dorsum, meaning back. The word is often paired with ventral, which refers to the belly or bottom side, but the exact orientation can vary with the organism and the context. In humans, the dorsal surface of the hand and the foot refers to the back of the hand or the top of the foot, while the dorsal aspect of the trunk means the back side.

In human and vertebrate anatomy, dorsal denotes structures toward the back of the body. The dorsal surface of the hand is opposite the palmar surface, and the dorsal surface of the foot is opposite the plantar surface. Dorsal terms are also used in describing anatomy of the nervous system, such as the dorsal horn and dorsal roots of the spinal cord, and in describing cavities like the dorsal body cavity, which includes the cranial and vertebral (spinal) cavities that protect the brain and spinal cord.

In zoology and comparative anatomy, dorsal refers to the upper or back side of an animal. Many fishes and marine mammals possess a dorsal fin along the back, while in some invertebrates and arthropods the dorsal surface bears particular structures or plates.

In clinical and veterinary contexts, dorsal is used to describe orientation, positions, or movements, such as dorsal recumbency in medical imaging, or dorsal flexion of the foot. The term provides a consistent shorthand for locating features relative to the back side of an organism.