page_title: Anatomical terms of location
section_title: Proximal and distal
hierarchical_section_title: Anatomical terms of location / Main terms / Proximal and distal
caption_attribution_description: English: Directional References. This image was donated by Blausen Medical. Please visit our website to see more medical illustrations and animations.
context_page_description: Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans.
  All vertebrates, including humans, have the same basic body plan: they are strictly bilaterally symmetrical in early embryonic stages and largely bilaterally symmetrical in adulthood. If they are divided down the middle, in other words, they have mirror-image left and right halves. For those reasons, the basic directional terms can be considered to be those used in vertebrates. By extension, the same terms are used for many other invertebrate organisms.
  While the terms are standardized within specific fields of biology, there are unavoidable, sometimes dramatic, differences between some disciplines. For example, differences in terminology remain a problem that to some extent still separates the terminology of human anatomy from the one that is used in the study of various other zoological categories.
context_section_description: The terms proximal (from Latin  proximus, meaning 'nearest') and distal (from Latin  distare, meaning 'to stand away from') are used to describe parts of a feature that are close to or distant from the main mass of the body, respectively. Thus the upper arm in humans is proximal and the hand is distal.
  These terms are frequently used when describing appendages such as fins, tentacles, limbs or any structure that extends that can potentially move separately from the main body. Although the direction indicated by "proximal" and "distal" is always respectively towards or away from the point of attachment, a given structure can be either proximal or distal in relation to another point of reference. Thus the elbow is distal to a wound on the upper arm, but proximal to a wound on the lower arm.
  This terminology is also employed in molecular biology and therefore by extension is also used in chemistry, specifically referring to the atomic loci of molecules from the overall moiety of a given compound.
caption: Anatomical directional reference
exif: {}