Before we take a look at the meaning of specific anatomical terms, I suppose the first question we should answer is, why do we use anatomical terms? Well, anatomical terms exist so that we can precisely describe the location of features on a body. Let's imagine the following scenario.
Here is a female. She's upset, and it's not just because she's naked on YouTube. It's mostly because she's just discovered a rather large pimple on her stomach.
But where exactly on her stomach is it? Statements like, there's something on my stomach, are so vague and non-specific, that they don't really mean anything to an anatomist. Is the pimple here, or here, or here?
or here. But if we use correct anatomical terminology, it's possible to precisely identify the location of her pimple, or any other body feature, so that anyone can precisely locate it. For example, if we're told that her pimple is 2cm superior to her navel or belly button, then its location becomes obvious to everybody, which is probably not what this female wants.
Before we move on from this picture, take a good look at how the woman's body is positioned in this drawing. Note how she's standing upright, arms at sides, palms facing forwards and feet together. We call this the anatomical position and it's the international standard position in which structures of the human body are described. Whenever you use anatomical terms, always apply them to a person standing in the anatomical position. Never apply them to say a person sitting on the ground or upside down or bent over sick after a heavy night out.
Okay, let's look at some anatomical terms. The first terms that we're going to define are the terms left and right. Now, I know what some of you are thinking.
Didn't we learn this in preschool? Well, even though you might think that the definitions of left and right are straightforward, Many students actually use these terms incorrectly. You see, when we use the terms left and right, we're referring to the left and right sides of the person standing in the anatomical position, which in this case is the woman in this drawing. We are not referring to the left and right sides of the observer, which in this case would be you looking at this drawing.
Consequently, for the woman in this picture This is her left side and this is her right side. So if you were asked in a test to describe the position of say point A relative to the umbilicus or belly button, the correct answer would be point A is to the left of the umbilicus. Okay next are the anatomical terms anterior and posterior. Anterior means front of the body whilst Posterior means back of the body.
In humans you can also use the term ventral for anterior and dorsal for posterior. Here are two examples of how you might use the terms anterior and posterior in a sentence. Example 1. The navel or belly button is on the anterior or ventral surface of the body. Example 2. The heel is on the anterior or ventral surface of the body.
posterior or dorsal to the toes. Next are the terms superior and inferior. Superior means above or towards the head.
Inferior means below or towards the feet. For example, on this drawing point A is superior to point B. However, point C is inferior to point B.
Next are two anatomical terms that you probably haven't heard before. They are proximal and distal. These terms are only used to describe the location of two points on the same limb, which could be either an arm or a leg. Proximal means closer to where the arm or leg inserts into the body. Distal means further.
further away from where the arm or leg inserts into the body. On this arm and leg, red arrows indicate proximal, whilst green arrows indicate distant. We can use the terms proximal and distal in the following ways.
On the leg, the knee is proximal to the ankle because the knee is closer to where the leg inserts into the body. But on the arm, the wrist is distal to the elbow because the wrist is further away from where the arm inserts into the body. Remember, only use the terms proximal and distal to determine the correct answer. when referring to two points on the same limb. If a point is no longer on a limb, like point A in this drawing, then you can't use the term proximal anymore.
Instead, point A would be superior to point B. Next are the terms medial and lateral. Medial means any point closer to the midline of the body. The midline is an imaginary line that cuts the body in half vertically. Lateral means any point away from the midline.
For example, in this drawing point A on the leg is medial to point B because point A is closer to the midline. Alternatively, you could say that point B is lateral to point A because point B is further away from the midline. Another example would be your thumb Being lateral to your little finger on your hand. Okay, now that you've mastered the basics, try to answer the following question.
Using correct anatomical terminology, can you describe the position of the nose relative to the eyes? I'll give you 5 seconds to work it out. Hopefully you answered the nose is medial, inferior and anterior to the eyes. So far, all of the anatomical terms that we've described are what we call directional terms.
That is, they're terms that describe the position of one external structure relative to another. But what happens if we want to observe the relative locations and arrangements of internal structures and organs? Like for example the heart, lungs and brain.
Well, to do this we need to cut the body into slices called sections or planes. The four anatomical planes are sagittal, frontal, transverse and oblique. A sagittal plane is a lengthwise or vertical cut that divides the body into left and right portions.
If the cut passes through the midline of the body then we call this a midsagittal plane. However if the cut doesn't exactly pass through the midline we call this a parasagittal plane. Next is the frontal plane.
This plane divides a body into anterior and posterior portions. For example a frontal section of the head would divide it into the face part and the back of the head part. Next we have the transverse plane.
This is a horizontal cut that divides the body into superior and inferior portions. Finally there is an oblique plane which passes through the body at, you guessed it, an oblique angle. The importance of understanding planes becomes obvious when you look at these three drawings of the brain cut in sagittal, frontal, and transverse section. Note how different each brain section appears and how some features, like for example the pons, are easy to see in one section but difficult to observe in others. Thanks for watching.
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