Welcome back to the channel where medical and science topics are made easy.
Today we’re going to talk about anatomical directional terms.
You’re going to learn simple tricks to remember the different anatomy terms that are shown,
so make sure to watch until the end.
You’ll also want to turn on the captions down below and
read along to help you remember everything.
So let’s jump right into it.
As we go through the different directional terms,
there needs to be a standard body position that we are using.
This is called the standard anatomical position.
You might remember from the previous video on body planes and sections
that the correct anatomical position is
standing upright,
with the head and eyes directed straight ahead.
The arms are hanging at the sides,
and slightly away from the trunk so they’re not touching the sides.
The palms are facing forward,
and the thumbs are pointing away from the body.
The legs are parallel,
and the feet are flat on the ground facing forward.
Finally, right and left refer to the patient’s right and left side
as indicated by the “R” and “L”.
So if you were looking at the patient the right side would be your left side,
and the left side would be your right side.
The anatomical position gives us a consistent, universal way of discussing anatomy.
And it creates clear reference points as we go through the different anatomical terms.
For more information on the anatomical position,
make sure to check out the previous video on body planes and sections because that goes into more detail.
It’ll be linked down below in the description.
The first pair of directional terms is medial and lateral.
To better understand medial and lateral,
let’s divide the body into right and left sections using a sagittal plane.
Remember in the previous video on body planes that the sagittal
plane runs vertically front to back, and it divides the body into right and left sections.
The line you see represents the midline of the body.
The midline is an imaginary vertical line down the middle of the body,
and it divides the body into equal right and left sections.
The easy way to remember the definition of midline is to think of “Midline” and “Middle”.
That midline is going to be our reference point when describing medial and lateral.
If we move toward the midline of the body, then we are moving medial.
So medial is defined as the middle or toward the midline or middle of the body.
In other words, we are moving away from the sides and toward the midline. This is medial.
Medial is simple to remember, use the letter “M” to think of medial, midline, and middle.
If we move away from the midline of the body, then we are moving lateral.
So lateral is defined as the side or toward the side of the body.
In other words, we are moving away from the midline and toward the sides. This is lateral.
Lateral can be remembered by thinking of your “lats”,
which are your side back muscles.
Let’s look at some examples of medial and lateral.
We can say the nose is medial to the eyes
because the nose is more toward the midline compared to the eyes.
We can also say the eyes are lateral to the nose
because the eyes are more toward the side of the body compared to the nose.
If the woman had 2 freckles on her face as shown on the image.
You could describe freckle 1 as being lateral to freckle 2,
or you could say freckle 2 is medial to freckle 1.
If we go back to our original image,
we can see the arms are lateral to the torso,
and the torso is medial to the arms.
We can also use directional terms for internal structures.
For example, the lungs are lateral to the heart.
And the heart is medial to the lungs as depicted by the image.
So hopefully medial and lateral make sense now.
Remember medial is toward the midline, and they both start with the letter “M”.
And lateral is toward the side, and the lat muscles stretch toward the side of the body.
The next pair of directional terms is superior and inferior.
This time we're going to divide the body into upper and lower portions using a transverse plane.
Remember in the previous video on body planes that the transverse plane runs horizontally,
and it divides the body into upper and lower sections.
That transverse line is going to be our reference point when describing superior and inferior.
If we move toward the head, then we are moving superior.
So superior is defined as above or toward the head.
You can think of superior and skull because they both start with the letter “S”
and this can help you remember superior is toward the head.
If we move away from the head, then we are moving inferior.
So inferior is defined as below or away from the head.
You can use the “F” in inferior to think of floor,
and this can help you remember inferior is toward the floor.
Superior and inferior also go by different names.
Another name for superior is cranial,
which makes sense because we are moving toward the cranium or head.
Another name for inferior is caudal.
Caudal means tail, so it makes sense that inferior is also known as caudal because we
are moving toward the tail or away from the head.
Let’s look at some examples of superior and inferior.
If we go back to our same image,
we can say the eyes are superior to the nose,
and the nose is superior to the mouth
because the eyes are above the nose, and the nose is above the mouth.
Or we can say the mouth is inferior to the nose,
and the nose is inferior to the eyes
because the mouth is below the nose, and the nose is below the eyes.
And if we go back to our freckle example,
we can see freckle 1 is superior and lateral to freckle 2,
and freckle 2 is inferior and medial to freckle 1.
If we go back to our original image,
we can see the head is superior to the torso,
and the torso is inferior to the head.
Finally, we can apply these terms to internal structures as well.
For example, the heart is superior to the liver.
And the liver is inferior to the heart.
Hopefully that explains superior and inferior.
Remember superior is toward the skull, and they both start with the letter “S”.
And inferior is toward the floor, and you can use the “F” in inferior to help you remember that.
Finally, don’t forget that superior can also go by cranial and inferior can also go by caudal.
You can also use these terms to describe different sides of a structure.
For example, if we look at the right lung,
this will be the lateral aspect because it is toward the side of the body,
and this will be the medial aspect because it is toward the midline.
The superior aspect will be the upper portion toward the head,
and the inferior aspect will be toward the floor away from the head.
Moving on to the next pair of directional terms, let’s look at anterior and posterior.
This time we're going to divide the body into front and back portions using a coronal plane.
Remember in the previous video on body planes that the coronal or frontal plane
runs vertically side to side, and it divides the body into front and back sections.
That coronal line is going to be our reference point when describing anterior and posterior.
If we move toward the front of the body, then we are moving anterior.
So anterior describes the front or toward the front of the body.
If we move toward the back of the body, then we are moving posterior.
So posterior describes the back or toward the back of the body.
“A” comes before “P” in the alphabet,
and this can help you remember anterior is in the front
and posterior is in the back.
Anterior and posterior also go by different names.
Another name for anterior is ventral, and another name for posterior is dorsal.
For ventral, you can think of a ventriloquist which literally translates to “stomach talker”.
We learned in our medical prefix video that the prefix “ventri-“
refers to the stomach, abdomen, or front of the body.
This can help you remember ventral means anterior.
For dorsal, you can think of the dorsal fin on the back of a fish
to help you remember dorsal means posterior.
Let’s look at some examples of anterior and posterior.
If we look at a side view of the brain,
we can see the frontal lobe is anterior to the occipital lobe,
and the occipital lobe is posterior to the frontal lobe.
You could also say the patella or kneecap is located on the anterior side of the leg,
and the olecranon or elbow is located on the posterior side of the arm.
The next pair of directional terms is proximal and distal.
These terms are most commonly used on the extremities and tubular structures.
If we move toward the trunk or point of attachment, then we are moving proximal.
So proximal is defined as toward the trunk or near the point of attachment or origin.
For proximal, you can think of the word proximity which means near or close.
If we move away from the trunk or point of attachment, then we are moving distal.
So distal is defined as away from the trunk or far from the point of attachment or origin.
For distal, you can think of the word distant which means far away from.
Let’s look at some examples of proximal and distal.
The wrist is proximal to the hand because the wrist is closer to the trunk than the hand is.
The elbow is proximal to the wrist because the elbow is closer to the trunk.
And the shoulder is proximal to the elbow because the shoulder is closer to the trunk.
Remember proximal means toward or closer to the trunk.
We can also say the elbow is distal to the shoulder because the elbow
is farther away from the trunk than the shoulder is.
The wrist is distal to the elbow because the wrist is farther away from the trunk.
And the hand is distal to the wrist because the hand is farther away from the trunk.
Remember distal means away from or farther from the trunk.
We can do the same with the lower extremities.
The ankle is proximal to the foot.
The knee is proximal to the ankle.
And the hip is proximal to the knee.
Again proximal means toward or closer to the trunk.
We can also say the knee is distal to the hip.
The ankle is distal to the knee.
And the foot is distal to the ankle.
Again distal means away from or farther from the trunk.
We also said proximal and distal can be applied to structures.
For example, if we look at the colon
the stool first travels up the ascending colon,
then through the transverse colon,
then down the descending colon.
Therefore, the red star on the ascending colon would be the proximal end of the
colon or large intestine, more specifically it is the proximal end of the ascending colon.
The green star is located more distal on the colon,
and that's because it's farther away from the starting point of the colon.
And more specifically it's located at the distal end of the descending colon.
The next pair of directional terms is superficial and deep.
If we move closer to the surface of the body, then we are moving superficial.
So superficial is defined as closer to the surface.
Superficial and surface both start with the letter “S” to help you remember this.
If we move away from the surface of the body, then we are moving deep.
So deep is defined as away from the surface of the body.
The term is self-explanatory which makes it easy to remember.
Let’s look at some examples of superficial and deep.
The skin is superficial to the ribs
and the ribs are superficial to the lungs.
Or you can say the lungs are deep to the ribs
and the ribs are deep to the skin.
Remember superficial means closer to the surface of the body,
and superficial and surface both start with the letter “S”,
while deep means away from the surface of the body.
Next we have unilateral and bilateral.
These terms are pretty straightforward.
Unilateral involves one side of the body.
For example, there could be a rash involving only the right arm as depicted by the star.
This would be a unilateral rash involving the right upper extremity.
We learned in the medical prefix video that “uni” means one or single,
which will help you remember unilateral involves one side of the body.
Bilateral involves both sides of the body.
For example, there could be a rash involving both arms as depicted by the 2 green stars.
This would be a rash to the upper extremities bilaterally.
We learned in the medical prefix video that “bi” means two or double,
which will help you remember bilateral involves both sides of the body.
Finally, we have ipsilateral and contralateral.
Ipsilateral means on the same side of the body.
For example, if a patient presents after a car accident with a laceration and an abrasion
on their right arm as depicted by the 2 stars, then those injuries are ipsilateral to one another.
We learned in the medical prefix video that “ipsi” means same,
which will help you remember ipsilateral means the same side of the body.
Contralateral means on opposite sides of the body.
For example, if a patient presents after a car accident with a laceration on their right arm
and an abrasion on their left arm, then those injuries are contralateral to each other.
We learned in the medical prefix video that “contra” means opposite,
which will help you remember contralateral means opposite sides of the body.
Hopefully this helped you better understand anatomical directional terms.
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