MAPPING THE BODY

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                 Anatomical Position

When an organism is in its standard anatomical position, positional descriptive terms are used to indicate regions and features.


Key Points

In standard anatomical position, the limbs are placed similarly to the supine position imposed on cadavers during autopsy.

The anatomical position of the skull is the Frankfurt plane. In this position, the lower margins of the orbitals (eye sockets), the lower margin of the orbits, and the upper margins of the ear canals (poria) lie in the same horizontal plane.

Because animals can change orientation with respect to their environments and appendages can change position with respect to the body, positional descriptive terms refer to the organism only in its standard anatomical position to prevent confusion.

Key Terms

Appendage : A limb of the body.


Anatomical position : The standard position in which the body is standing with feet together, arms to the side, and head, eyes, and palms facing forward.


Supine : Lying on its back, reclined.


The Need for Standardization

Standard anatomical position is the body orientation used when describing an organism's anatomy.  Standardization is necessary to avoid confusion since most organisms can take on many different positions that may change the relative placement of organs. All descriptions refer to the organism in its standard anatomical position, even when the organism's appendages are in another position. Thus, the standard anatomical position provides a "gold standard" when comparing the anatomy of different members of the same species.



Relative location in the anatomical position

Many terms are used to describe relative location on the body. Cranial refers to features closer to the head, while caudal refers to features closer to the feet. The front of the body is referred to as anterior or ventral, while the back is referred to as posterior or dorsal. Proximal and distal describe relative position on the limbs. Proximal refers to a feature that is closer to the torso, while distal refers to a feature that is closer to the fingers/toes. Medial and lateral refer to position relative to the midline, which is a vertical line drawn through the center of the forehead, down through the belly button to the floor. Medial indicates a feature is closer to this line, while lateral indicates features further from this line.


This image shows two female figures to demonstrate correct anatomical position labeling. The figure at left is turned to the side, with labels indicating that cranial refers to features toward the head while caudal refers to features that are closer to the feet. The front of the body is referred to as anterior or ventral, while the back is referred to as posterior or dorsal. The figure at right is facing forward in standard anatomical position. Labels indicate that proximal and distal are used to refer to the top and bottom of limbs, respectively. Medial is the term used for the center of the body, and lateral refers to features that are parallel to the medial.

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