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

The anatomical position, with terms of relative location noted.

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.

Standard Anatomical Position in Humans

The standard anatomical position is agreed upon by the international medical community. In this position, a person is standing upright with the lower limbs together or slightly apart, feet flat on the floor and facing forward, upper limbs at the sides with the palms facing forward and thumbs pointing away from the body, and head and eyes directed straight ahead. In addition, the arms are usually placed slightly apart from the body so that the hands do not touch the sides. The positions of the limbs, particularly the arms, have important implications for directional terms in those appendages. 

The basis for the standard anatomical position in humans comes from the supine position used for examining human cadavers during autopsies. Dissection of cadavers was one of the primary ways humans learned about anatomy throughout history, which has tremendously influenced the ways by which anatomical knowledge has developed into the scientific field of today.

Standard anatomical position

The regions of the body in standard anatomical position, in which the body is erect.

In humans, the standard anatomical position of the skull is called the Frankfurt plane. In this position, the orbitales (eye sockets), lower margins of the orbits, and the poria (ear canal upper margins) all lie in the same horizontal plane. This orientation represents the position of the skull if the subject were standing upright and looking straight ahead.

It is important to note that all anatomical descriptions are based on the standard anatomical position unless otherwise stated.