Medial vs Lateral

When describing the human body, a good way to avoid confusion is by adopting the universal language used by anatomists and healthcare professionals alike. Today, we're going to explore two of these terms, which are the words lateral and medial. You might be wondering why we're taking the time to explain something so simple, however, I know some of you are like me and struggle with your rights and lefts, so, it's definitely worth taking a few minutes to get familiar with these terms.

To understand these concepts, you must first of all know that directional terms in anatomy refer to a human body that's in the anatomical position. The concept of the anatomical position refers to a standing body looking straight ahead with the feet apart and pointing forward, its arms hanging down on both sides with the palms facing forward.

So now that we've defined the anatomical position, let's get on to our first term.

Lateral simply refers to something away from the midline of the body. So, here, we can see a line running through our lovely model, which is called the midsagittal plane. This plane runs through the midline of the body and anything located on either side of it can be lateral. However, it gets slightly more complicated when we add the term medial to the mix. Medial refers to something towards the midline of the body. In this instance, it means something closer to the midline.

For example, our poor model here – let's call him Fred – has managed to get a few cuts and scrapes. If we put a purple plaster on Fred's trunk, we can say that this plaster is lateral to the midline of the body. However, if we add a blue plaster to his arm, we can also say that the purple plaster is medial to the blue plaster or that it's located medially as it is closer to the midline, whereas the blue plaster is lateral to the purple plaster or located laterally since it is further away from the midline. Does that make sense? I hope so.

We also use these terms to determine from what viewpoint we're looking at the body or one of its many parts. So, here, we have a lateral view of the skull which essentially means that we're looking at it from the side, whereas if we cut down the midsagittal plane, we can see a medial view of the skull. This view allows us to see structures that are closer to the midline of the body.

Medial and lateral are easy concepts to master and you can get really familiar with them if you use them every day. For example, if your friend spills some ketchup on their shirt, try and figure out whether it's located laterally or medially.

So that brings us to the end of our tutorial about the terms lateral and medial. If you're curious to find out more about directional terminology and anatomy, please be sure to check out our website.

Thanks for watching and see you next time.