Standard Anatomical Position

Abbott & Costello – Who's on First

Bioarchaeological labs can be confusing places. Witness the following interaction, which takes place at least once a season:

Bioarch 1: “This fragment’s a humerus, right?”
Bioarch 2: [Examines bone] “No, it’s a left.”
Bioarch 1: “But it’s humerus?”
Bioarch 2: “Right.”
Bioarch 1: “I thought you said it was from the left!?”
Bioarch 2: “Right!”

[Repeat ad nauseam until both scientists tear out their hair in frustration]

In order to avoid this Who’s on First? level of slapstick, I have instituted a policy of saying “correct” instead of “right” when in agreement about something involving human bones. Another helpful tactic that bioarchaeologists and anatomists use to avoid confusion is to ensure that bones are always oriented in Standard Anatomical Position.

In The Human Bone Manual, White describes Standard Anatomical Position (SAP) as “Standing with feet together and pointing forward, looking forward, with none of the long bones crossed from viewer’s perspective and palms facing forward” (426: 2005). The first page of Anderson’s The Human Skeleton: A Manual for Archaeologists, notes that “In describing the human body, all references are related to what is known as the ANATOMICAL POSITION. That is, we consider the individual to be standing erect, with feet together, eyes facing straight ahead, and hands at the side with palms facing forward” (1: 1962).

An Introduction to Human Evolutionary Anatomy specifies that “Anatomical descriptions are always made with the body positioned in the anatomical position…sometimes this has to be imagined, because the bone or specimen under consideration is actually lying on a table or is still half buried in the ground. The anatomical position is that assumed by a standing person with the upper limbs at the side and with the face, palms of the hands and feet pointing forwards”(2002: 16). Finally, Baker et al. describe how “… the adult human skeleton is typically oriented in a standing posture with no bone crossing over another. Thus, the legs are together with the toes pointing forward and the arms are at the sides with the palms facing forward…While standard anatomical position is based on the adult skeleton, it pertains to any child who has begun to walk. For fetuses and infants who have not yet begun to walk, the body can be envisioned in a supine position (on the back), with the toes pointing up and the palms facing up along the sides of the body” (2005:7).

I struggled with these kinds of technical definitions when I was an osteology student, and found visual or hands-on demonstrations far more effective. If, for example, you’re into yoga, you’re already familiar with SAP as “mountain pose.”

You can also think of it as the standing version of one of my favorite* yoga poses, corpse pose:

*Because I am lazy.

If, however, you are not a yoga practitioner, another helpful test of your understanding of SAP is the examination of the sleeping positions of our canine companions. I have noticed that sleeping puppies will often default to the human Standard Anatomical Position, though they always accidentally pronate their front paws . Let’s take a look, shall we?


Addendum
: I must confess that  when I analyze the bones of the hands, particularly the metacarpals, I analyze them as if they are pronated, and not in SAP. This is because I am a poor osteologist – do as I say, and not as I do!

References
Aiello, L., and C. Dean. 2002. An Introduction to Human Evolutionary Anatomy. Elsevier, London.

Anderson, J.E. 1962. The Human Skeleton: A Manual for Archaeologists. The National Museum of Canada. Roger Duhamel F.R.S.C.: Ottawa.

Baker, B.J., T.L. Dupras, and M.W. Tocheri. 2005. The Osteology of Infants and Children. Texas A&M University Press, College Station.

White, T. D., and P.A. Folkens. (2005) The Human Bone Manual. Elsevier, Amsterdam.

Image Credits: Abbot and Costello image from Aurora’s gin joint, found here.  Skeleton in SAP found at auriea.org, here. Mountain pose in anterior view from North Shore University, here, and in lateral view from Greatist, here. Corpse pose from fitfluential, found here. SAP Puppy 1 from the Daily Puppy, found here; SAP Puppy 2 from found here; SAP Puppy 3 from Barkpost, found here; SAP puppy 4 found here; SAP Puppy 5 from Patti Brehler on blogspot, found here.

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4 Responses to Standard Anatomical Position

  1. Excellent post! I tried writing a post a while ago on the origin of the anatomical position in osteology but never quite got anyway, just a mess of European Journal of Anatomy articles!

    Like

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