Standard anatomical position
Because animals can change orientation with respect to their environment, and because appendages (arms, legs, tentacles, etc.) can change position with respect to the main body, it is important that anatomical terms of location refer to the organism when it is in its standard anatomical position.
Thus, all descriptions are with respect to the organism in its standard anatomical position, even when the organism in question has appendages in another position. However, a straight position is assumed when describing the proximo-distal axis. This helps avoid confusion in terminology when referring to the same organism in different postures.
Thus, all descriptions are with respect to the organism in its standard anatomical position, even when the organism in question has appendages in another position. However, a straight position is assumed when describing the proximo-distal axis. This helps avoid confusion in terminology when referring to the same organism in different postures.