Anatomy for dummy’s, vol. 1: Anatomical direction terms
By Jasper Remmerswaal
Terminology for reading this article:
- Hamstrings: The muscles on the back of your body, between the knees and the butt.
- Glutes: The gluteal muscles. Your ass.
- Spinal erectors: The muscles that run along your back that assist in extending the back.
- Rotator cuff: A group of muscles responsible for keeping the top of the arm in place with the shoulder.
This article is part of a series of articles and will be a small introduction into understanding anatomy. These articles will briefly explain the universal language that is used in anatomy and the physical therapist discipline. In this article,
the anatomical position and the anatomical directions are explained.
The anatomical position
The first thing that has to be kept in mind is that when anatomical directions and terms are discussed, they are always relative to the anatomical position (see picture). This agreement has been made because simple left/right and up/down does not cut it. Easy example: Up and down changes if someone is standing up compared to when someone is lying down. The agreement is, that every position is related to the anatomical position so there won’t be misunderstandings.
The anatomical position is: standing straight up, feet closely together and the palms turned forward. This position is always used when articles refer to places on the body.
Now that the anatomical position is defined, the anatomical directions can be defined. If the Dutch translations are different from the English terms, the correct Dutch translation is given. If there is no extra translation, you can assume that the term is the same, or very similar in Dutch. Sometimes a small explanation is given in Dutch to make things more clear for Dutch readers. I have added pictures.
The anatomical directions
All anatomical directions come in pairs of two, with the pair being each other’s opposite.
Anterior – posterior
Anterior refers to the front of the body, while posterior refers to the back of the body. In the literal sense, anterior means ‘’in front of’’ vs. posterior ‘’behind off’’. In Dutch: ‘’Aan de voor/achterzijde gelegen’’. The deltoid muscles, your three-headed shoulder muscle complex is a good example of this. There is the posterior deltoid muscle, located on the backside of the body, the medial/lateral (explained later) deltoid muscle and the anterior deltoid muscle, located on the front of the body. Also, a common term, the posterior chain is mentioned quite often in articles. This posterior chain term refers to the hamstrings, glutes and lower back/spinal erectors (the posterior chain includes more muscles: A more thorough explanation is beyond the scope of this article). This chain is located on the backside of the body, hence the name posterior chain.
Ventral – Dorsal
Ventral is a synonym for ‘’towards the front of the body’’ while dorsal means ‘’towards the back of the body’’. ‘’Venter’’ is Latin for ‘’stomach’’, while ‘’dorso’’ is Latin for ‘’back’’. Example: lattisimus dorsi. The name of this muscle tells you that it is a back muscle because of the word ‘’dorsi’’.
You might have noticed that the pair anterior – posterior and the pair ventral – dorsal are very much alike. This is correct and they are practically each other’s synonym. The reason both are mentioned here is because both are used (medical science is really not that consistent in its terminology). An example to make this clear: the anterior deltoid, is on the ventral side of the body.
Sinistero – dextro
Sinister simply means ‘’to the left’’ of the body, while dextro means ‘’to the right’’. Don’t forget that these positions are related to the anatomical position. Left and right are defined from the anatomical position’s (or patient’s) point of view. In practice, these terms are never used but I thought it was really important to mention them because the terms are much like the Italian words for ‘’right’’ and ‘’left’’ meaning you are now able to say ‘’Go left!’’ to your annoying taxi driver, when in Rome (the correct Italian terms are destra & sinistra by the way, but he will understand). You’re such an educated, multicultural guy, you.
Distal – proximal
Distal refers to the point furthest away from the trunk ór the origin of the body part, while proximal refers to the point closest to the trunk (romp in Dutch) ór closest to the origin of the body part. An example would be that your toe lies more distal compared to your knee (because the toe’s lie further from the trunk than the knee. An extra explanation for the ‘’closer/further from the origin’’: When we talk about distal/proximal in relation to limbs ( ledematen in Dutch), you can say that the hand is more distal than the shoulder (or the shoulder is more proximal), because the shoulder is closer to the attachment of the body.
Medial – lateral
The ‘median’ first has to be defined in order to explain these terms. The median is simply the midline from the top of your skull down to the floor, splitting you in two equal parts, left and right. The term medial refers to something lying towards the midline, while lateral refers to something lying towards the outside of the body. An example: The shoulders lie lateral when compared to the knees. The knees lie more towards the midline of the body, and therefore lie more medial. Fun fact: The term medial deltoid, which is often used to describe the 2nd deltoid muscle (so the one in the middle) is actually wrong. Lateral would be a more appropriate description. When someone says: ‘’That’s a good exercise for your medial deltoid bro!’’, hit them over the head with a barbell.
Superior – inferior (In Dutch often called Craniaal – Caudaal)
Superior refers to ‘’towards the top of the head’’, while inferior refers to ‘’towards the feet’’. An example would be two of the four muscles of the rotator cuff (hardcore explanation: the muscle group responsible for holding the top of the humerus in the gleno-humeral socket): The supraspinatus and the infraspinatus. It doesn’t really matter whether you understand what these muscles are and what they do. The thing to realize here, is that supra refers to ‘’towards the head’’, while infra refers to ‘’towards the feet’’. See picture. Thus you can determine the place of the muscles in relation to each other, even without looking at a picture. The supraspinatus is located higher than the infraspinatus.
Internal – external (In Dutch often called centraal – perifeer)
Internal refers to ‘’the inside of the body’’, while external refers to ‘’the outside of the body’’. For the average reader the take-home message here is that these terms are often combined with rotation. The shoulder joint and hip joint are both joints where internal and external rotation takes place (in Dutch: endo- en exorotatie). For the shoulder this can be demonstrated by sticking the arms out, like a zombie, with the palms down, facing the floor. Then turn the palms to the ceiling and watch what happens at the shoulder. The shoulders turn outward: external rotation. Reversing this process is then called internal rotation of the shoulder. At the hip joint, external rotation takes place by turning the feet outwards (‘flaring’ the feet). The femur (the thighbone) will turn outwards: external rotation. Reversing this process is then called internal rotation of the femur. See picture.
I hope you enjoyed this article and learned something. Hopefully, you will suddenly recognize these terms in the articles that you read and you may even start to understand the anatomical language. I also hope you are now able to overcomplicate simple concepts, by using words that most people do not know. This wíll make you look smarter and superior to other people, which is a good thing. Say things like ‘’your knees have a tendency to move medial in your squat’’ instead of ‘’your knees move in bro’’. Sound smart, don’t be smart. Being smart takes too much time. That’s it for the anatomical directional terms. In the next article, I will try to ‘Jip en Janneke’ the basic movements planes and axes for you.
References used for inspiration
- Snellenberg, W. (2016). Handboek sportmassage (13de druk). Utrecht: Kosmos Uitgevers.
- Myos opleidingen, (2016, 6 november), Anatomie [Powerpoint].
- Joe., & https://www.kenhub.com/eC. Chaves. (2013, 1 december). Directional Terms and Body Planes Consulted 10-10-2016, n/library/anatomy/directional-terms-and-body-planes