How to easily remember description of direction in anatomy

Today human anatomy is regarded as being a complete science. The “what is where” of the human body is largely known. But, remember as you struggle to learn anatomical names that it took about 3600 years to make it a complete science.

Composite figure of hands pointing in different directions

Which way? Photo by vadimmmus at Shutterstock.com

Ancient anatomists had their problems too. They needed reference points upon which to base their description of “what is where”. A uniform description of three dimensional anatomic orientation was devised in early studies, and it was largely kept and expanded upon. It is easier to communicate when everyone uses the same words.

anatomical position is reference for location of body parts in human anatomy

Anatomical Position, Skeleton illustration by Alex Luengo at Shutterstock.com

A first issue to arise in naming human parts was the number of positions that flexible human bodies can acquire. A single position was needed that could be used as a reference for describing where the pieces were relative to each other. That single position became known as the “anatomical position” and is displayed by this skeleton. No matter what position a cadaver assumed, all descriptions were extrapolated back to where the body part would be in the “anatomical position”.

It takes a bit of imagination and focus to transfer what you are looking at into the anatomical position of another person. That is a standing person, head and eyes facing forward, feet together, arms to side, palms of hands facing forward.

Problems arise if you do not remember that for a person you are facing right and left may be reversed. Only if each of you is facing the same direction are right and left the same.

To get answers correct on anatomy practical exams, it is identification of the right and left body part that is important. Some of us become confused with the issue of right and left, because we are so accustomed to mirror images of ourselves. It is easy to forget that our mirror image is the reverse of our real self. Some people are uncomfortable with pictures of themselves, because a picture is not their mirror image.

human hands displaying bilateral symmetry

Bilateral Symmetry of Human Hands, Photo by missanzi at Shutterstock.com

Humans are said to be bilaterally symmetrical. The directional term lateral is used as a modifier for both sides of the body, left lateral and right lateral. As opposed to lateral, the term median is used to define a point in the center of the organism. The term medial means toward the median plane of the person.

For descriptors to remain fixed in their meaning the anatomic position is critical. Imagine where the bones of the forearm, the radius and the ulna, would be if our skeleton had the palms of its hands facing backward rather than forward. In the anatomic position, palms forward, the radius bone lies lateral and the ulna bone is medial. With rotation of the forearm as the palms turn toward the back, the radius moves to a medial position and the ulna is then lateral.

Appendages, arms, legs, and pelvis often move independently of the torso of the body. So, separate directional terms are used to describe them. The term proximal describes where the appendage joins the torso of the body. The term distal is used for the point farthest from the point of attachment to the torso. Proximal and distal are often used as relative terms. For example, the elbow is proximal to the hand . . .the elbow is closer to where the arm attaches to the torso than the hand is, but the elbow is distal to the shoulder . . .the elbow is in a position further away from the torso than the shoulder joint.

In the scheme of human orientation descriptors anterior is toward the front while posterior is toward the back. Superior is toward the head. The opposite term, inferior, is a relative descriptor generally used to mean below some other body part. Internal body organs are described as superficial meaning near the body surface, or deep meaning internal and away from the surface.

In most anatomy courses these human body orientation descriptors are learned early in the instruction. They are learned in isolation. Because anatomy descriptors appear easy you may not want to focus much of your precious time studying them. It all seems so obvious that it is natural to think, “I know that”.

Orientation descriptors are not used a lot until your instructor hands out long lists of muscles, nerves, and blood vessels to be learned. By then your memory of orientation descriptors may be lost in the fog of too many facts accumulated since the descriptors were last thought about.

The trick is not to blow off these terms early in your study of anatomy. Make friends with them instead. Practice describing all body structures you learn with these descriptors. It may feel strange at first, but stick with it.

Human rib cage with sections of the sternum in colors

The sternum’s parts are colored green, blue, and purple; illustration by Anatomography, WikiMedia Commons

For example when learning bones, you can decide whether the human sternum (colored set of bones) is located anterior or posterior, inferior or superior to the pelvis, medial or right lateral or left lateral when the body is in the anatomic position. In doing this, you will remember why you do not use the terms proximal and distal to locate the sternum.

Do this, and when it comes time to learn names of muscles, nerves, blood vessels you will be way ahead of your classmates.

There is a box below where I hope you will tell me if knowing the logic behind anatomical descriptions of orientation helps you remember and use them properly. Also, I would like your help in choosing other topics for future articles. Please tell me what areas of anatomy you find the most frustrating.

You may also like to read about the patterns used in naming Human Body Muscles. If you are struggling with your anatomy lab exams check out five ways to make the best of them in the post Anatomy Lab Tests.

Do you have questions?

Please put your questions in the comment box or send them to me by email at DrReece@MedicalScienceNavigator.com. I read and reply to all comments and email.

If you find this article interesting share it with your fellow students or send it to your favorite social media site by clicking on one of the buttons below.

Reece-4-S2S14-001Margaret Thompson Reece PhD, physiologist, former Senior Scientist and Laboratory Director at academic medical centers in California, New York and Massachusetts and Chief Scientific Officer at Serometrix LLC is now CEO at Reece Biomedical Consulting LLC.

Dr. Reece is passionate about helping students, online and in person, pursue careers in life sciences. Her books “Physiology: Custom-Designed Chemistry” (2012), “Inside the Closed World of the Brain” (2015) and  the workbook (2017) companion to her online course “30-Day Challenge: Craft Your Plan for Learning Physiology”  are written for those new to life science. Dr. Reece’s books can be found at amazon.com/author/margaretreece.

Dr. Reece offers a free 30 minute “how-to-get-started” conference call for students struggling with human anatomy and physiology. Schedule an appointment by email at DrReece@MedicalScienceNavigator.com.


Comments

Orientation in Anatomy — 8 Comments

  1. I’ve always found this very confusing. I thought with the brain the left hemisphere would be on the right with the anatomical position, but is that wrong based on the above description? When it comes to reading various things I’m never really sure from what point of view or position in space/on the body it’s in reference to.

    Do you happen to recommend any books?

    • Margaret Reece, PhDMargaret Reece, PhD on said:

      Hello Chris, The problem you are having with right and left is a very common one for students. It helps to put yourself in the anatomic position for comparison. For example, if you are learning an articulated human skeleton, stand behind the skeleton to determine its right and left. From behind your right and left match the skeleton’s right and left. It is only when two people in the anatomic position are facing each other that things seem reversed.

  2. My name is Rosa .
    I took Anatomy and Physiology and pass with a D and I decide to take it again. I study hard and when it come to my practical and test I get bad grades. I get frustrated and upset because I study so hard and I don’t know what I’m doing wrong I’m thinking to drop the class . I don’t want another D . I want to pass with A . What is your suggestion please help me what should I do .

    • Margaret Reece, PhDMargaret Reece, PhD on said:

      Hi Rosa, I think you are asking about lab practical exams, but you must be having problems in lecture as well. I think you must be taking first semester A&P, but the topics for each semester vary by school. Send me an email at DrReece@MedicalScienceNavigator.com and we can talk more about your specific problems with the material.

  3. Mona Pruity on said:

    Why does people tell you that A&P is so difficult to pass?

    • Margaret Reece, PhDMargaret Reece, PhD on said:

      I am told that the anatomic names are hard to memorize because they are unfamiliar words. I way around that problem is to get out the dictionary and find the root words’ meaning in your native language. For example part of neuron is its dendrites. The word dendrite translates from Latin into ‘tree’. And, neuron dendrites look like branches on a tree. Physiology is a different problem. In A&P courses it is taught in the same sequence as the anatomy, and it is hard for students to see the whole of it when it is broken up into such small pieces.

  4. Christina Walton on said:

    Im having trouble uderstanding this question to find the answer.

    “Why do you need to know body orientations and direction when talking about the human body?

    • Margaret Reece, PhDMargaret Reece, PhD on said:

      Because muscle names often include the direction of the movement they elicit in their name. Direction needs a common starting point for the names to make sense.

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