Anatomical Position and Directional Terms
Simple review of the anatomical position and directional terms! Includes definitions and example labeled diagrams for medial, lateral, proximal, distal, superior, inferior, anterior, posterior, and much more!
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Anatomical Directional Terms
Looking for a simple resource that clearly defines the anatomical position and directional terms?
Welcome! You have come to the right spot!
We will first review the anatomical position, its definition, and look at example labeled diagrams.
We will then walk through the different anatomical directional terms used to describe location and movement.
We will provide you with labeled diagrams, example body parts, and tricks to learn the directional terms listed below!
Medial vs Lateral
Superior vs Inferior (Cranial vs Caudal)
Anterior vs Posterior (Ventral vs Dorsal)
Proximal vs Distal
Superficial vs Deep
Unilateral vs Bilateral
Ipsilateral vs Contralateral
The above anatomical terminology can be used clinically or when looking at different anatomy body planes and sections.
We discussed anatomical planes and sections in the previous lecture and now this will help to bring it all together!
Let’s get started!
Anatomical Directional Terms: Medial, lateral, superior, inferior, anterior, posterior, proximal, distal, superficial, deep, unilateral, bilateral, ipsilateral, and contralateral.
Anatomical Position
In order to learn the different anatomical directional terms, we need to have a standard body position we can use as a reference.
This standard body position is called the standard anatomical position.
You might remember from the previous lecture on body planes and sections that the correct anatomical position is the following:
Standing upright
Head and eyes directed straight ahead
Upper limbs hanging down at the sides
Upper limbs slightly away from the trunk so the hands are not touching the sides
Palms facing forward
Thumbs pointing away from the body
Lower limbs parallel
Feet 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” below.
In other words….
If you were looking at the patient, then the right side would be on your left and the left side would be on your right.
The anatomical position gives us a consistent, universal way of discussing anatomy.
Moreover, it will create clear reference points as we walk through the different anatomical terms below.
Anatomical Position: The standard body position is used to describe anatomical directional terms, body planes and sections, and anatomy definitions.
Medial vs Lateral
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.
You might remember in the previous lecture on body planes that the sagittal plane runs vertically front to back, and it divides the body into right and left sections.
Midline
The line you see below represents a sagittal plane through the midline of the body.
The midline (median plane or midsagittal plane) is an imaginary vertical line down the middle of the body, and it divides the body into equal right and left sections.
You can think of “midline” and “middle” to remember the definition of midline.
The midline will be our reference point when describing medial and lateral.
Anatomical Directional Terms: A midsagittal plane through the midline of the body will be used as our reference point for medial and lateral.
Medial
If we move toward the midline of the body, then we are moving medial.
Therefore, 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 easy to remember, simply use the letter “M” to think of “Medial”, “Midline”, and “Middle”.
Anatomical Directional Terms: Labeled diagram showing medial, defined as toward the midline or middle of the body.
Lateral
If we move away from the midline of the body, then we are moving lateral.
Therefore, 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 the back muscles that stretch to the sides.
Anatomical Directional Terms: Labeled diagram showing lateral, defined as toward the side of the body.
Examples of Medial and Lateral
Let’s start with some basic examples of medial and lateral.
We can say the nose is medial to the eyes, as the nose is more toward the midline compared to the eyes.
Or we can say the eyes are lateral to the nose, as the eyes are more toward the side of the body compared to the nose.
Anatomical Directional Terms: Example of medial and lateral using the eyes and nose.
Examples of Medial and Lateral
Let’s say 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.
Anatomical Directional Terms: Examples of medial and lateral using freckles on the face.
Examples of Medial and Lateral
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.
Anatomical Directional Terms: Examples of medial and lateral using the torso and arms.
Examples of Medial and Lateral
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.
Anatomical Directional Terms: Examples of medial and lateral using the heart and lungs.
Summary of Medial and Lateral
Hopefully medial and lateral make more sense now.
Remember medial is toward the midline, and “Medial”, “Midline”, and “Middle” all start with the letter “M”.
Lateral is toward the side, and the “Lat” muscles stretch toward the side of the back.
Superior vs Inferior
The next pair of directional terms is superior and inferior.
Rather than dividing the body into right and left sections like we did above, we will now divide the body into upper and lower portions using a transverse plane.
You might recall in the previous lecture on body planes that the transverse plane runs horizontally, and it divides the body into upper and lower sections.
The transverse line below will be our reference point when describing superior and inferior.
Anatomical Directional Terms: A transverse plane will be used as our reference point for superior and inferior.
Superior
If we move toward the head, then we are moving superior.
Therefore, superior is defined as “above or toward the head”.
You can think of “Superior” and “Skull” which both start with the letter “S” to help you remember superior is toward the head.
Anatomical Directional Terms: Labeled diagram showing superior, defined as above or toward the head.
Inferior
If we move away from the head, then we are moving inferior.
Therefore, 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.
Anatomical Directional Terms: Labeled diagram showing inferior, defined as below or away from the head.
Superior (Cranial) and Inferior (Caudal)
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, which makes sense because we are moving toward the tail away from the head.
Anatomical Directional Terms: Another name for superior is cranial, and another name for inferior is caudal.
Examples of Superior and Inferior
Let’s start with some basic examples of superior and inferior using our same image.
We can say the eyes are superior to the nose, as the eyes are above the nose.
We can also say the nose is superior to the mouth, as the nose is above the mouth.
Or we can say the mouth is inferior to the nose, as the mouth is below the nose.
We can also say the nose is inferior to the eyes, as the nose is below the eyes.
Anatomical Directional Terms: Examples of superior and inferior using the eyes, nose, and mouth.
Examples of Superior and Inferior
If we go back to our freckle example, we can see freckle 1 is superior and lateral to freckle 2.
Or we can say freckle 2 is inferior and medial to freckle 1.
Anatomical Directional Terms: Examples of superior and inferior using freckles on the face.
Examples of Superior and Inferior
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.
Anatomical Directional Terms: Examples of superior and inferior using the head and torso.
Examples of Superior and Inferior
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.
Anatomical Directional Terms: Examples of superior (cranial) and inferior (caudal) using the heart and liver
Summary of Superior and Inferior
Hopefully that clearly explains superior and inferior.
Remember “Superior” is toward the “Skull”, and they both start with the letter “S”.
Inferior is toward the “Floor”, and you can use the “F” in inferior to help you remember this.
Do not forget another name for superior is cranial, and another name for inferior is caudal.
Summary of Superior, Inferior, Medial, and Lateral
Superior, inferior, medial, and lateral can also be used to describe different sides of a structure.
Let’s look at the right lung as an example.
The outer border toward the side of the body will be the lateral aspect of the right lung.
The inner border toward the midline of the body will be the medial aspect.
The upper portion toward the head will be the superior aspect of the lung.
Finally, the inferior aspect will be toward the floor away from the head.
Anatomical Directional Terms: Example labeled diagram of medial, lateral, superior, and inferior using the right lung.
Anterior vs Posterior
The next pair of directional terms is anterior and posterior.
Rather than dividing the body into right and left sections or upper and lower sections, we will now divide the body into front and back portions using a coronal plane.
Remember in the previous lecture on body planes that the coronal or frontal plane runs vertically side to side, and it divides the body into front and back sections.
The coronal line below will be our reference point when describing anterior and posterior.
Anatomical Directional Terms: A coronal (frontal) plane will be used as our reference point for anterior and posterior.
Anterior and Posterior
If we move toward the front of the body, then we are moving anterior.
Therefore, anterior is defined as “the front or toward the front of the body”.
If we move toward the back of the body, then we are moving posterior.
Therefore, posterior is defined as “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.
Anatomical Directional Terms: Labeled diagram of anterior (front; toward the front of the body) and posterior (back; toward the back of the body).
Anterior (Ventral) and Posterior (Dorsal)
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 lecture 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.
Anatomical Directional Terms: Another name for anterior is ventral, and another name for posterior is dorsal.
Examples of Anterior and Posterior
Let’s review examples of anterior and posterior by looking at a side (sagittal) view of the brain.
We can see the frontal lobe is anterior to the occipital lobe, as the frontal lobe is more toward the front of the body.
We can also see the occipital lobe is posterior to the frontal lobe, as the occipital lobe is more toward the back of the body.
Anatomical Directional Terms: Examples of anterior and posterior using the frontal and occipital lobes of the brain.
Examples of Anterior and Posterior
You could also say the patella (kneecap) is located on the anterior side of the leg, and the olecranon (elbow) is located on the posterior side of the arm.
Anatomical Directional Terms: Examples of anterior and posterior using the patella (kneecap) and olecranon (elbow).
Summary of Anterior and Posterior
Hopefully that helped clarify anterior and posterior.
Remember “A” comes before “P” in the alphabet, and this can help you recall anterior is toward the front and posterior is toward the back.
Do not forget another name for anterior is ventral. Just think of ventriloquist!
Another name for posterior is dorsal. Just think of a dorsal fin on a fish!
Proximal vs Distal
The next pair of directional terms is proximal and distal.
Proximal and distal are most commonly used on the extremities and tubular structures.
Proximal
If we move toward the trunk or point of attachment, then we are moving proximal.
Therefore, 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.
Anatomical Directional Terms: Labeled diagram showing proximal, defined as toward the trunk or near the origin/point of attachment.
Distal
If we move away from the trunk or point of attachment, then we are moving distal.
Therefore, 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.
Anatomical Directional Terms: Labeled diagram of distal, defined as away from the trunk or far from the origin/point of attachment
Examples of Proximal and Distal
Let’s look at some examples of proximal and distal.
The wrist is proximal to the hand, as the wrist is closer to the trunk than the hand.
The elbow is proximal to the wrist, as the elbow is closer to the trunk than the wrist.
The shoulder is proximal to the elbow, as the shoulder is closer to the trunk than the elbow.
Remember proximal means toward or closer to the trunk.
We can also say the elbow is distal to the shoulder, as the elbow is farther away from the trunk than the shoulder.
The wrist is distal to the elbow, as the wrist is farther away from the trunk than the elbow.
The hand is distal to the wrist, as the hand is farther away from the trunk than the wrist.
Remember distal means away from or farther from the trunk.
Anatomical Directional Terms: Examples of proximal and distal using the arms.
Examples of Proximal and Distal
The same example can be applied to the legs.
The ankle is proximal to the foot, as the ankle is closer to the trunk than the foot.
The knee is proximal to the ankle, as the knee is closer to the trunk than the ankle.
The hip is proximal to the knee, as the hip is closer to the trunk than the knee.
Again proximal means toward or closer to the trunk.
We can also say the knee is distal to the hip, as the knee is farther away from the trunk than the hip.
The ankle is distal to the knee, as the ankle is farther away from the trunk than the knee.
The foot is distal to the ankle, as the foot is farther away from the trunk than the ankle.
Again distal means away from or farther from the trunk.
Anatomical Directional Terms: Examples of proximal and distal using the legs.
Examples of Proximal and Distal
We also said proximal and distal can be applied to structures.
Let’s use the colon as an example.
The first part of the colon after the cecum (connects the large and small intestine) is the ascending colon.
The next part is the transverse colon, followed by the descending colon, sigmoid colon, and rectum.
Therefore, the red star below (on the ascending colon) would be the proximal end of the colon or large intestine, as it is located at the point of origin or attachment of the structure.
More specifically, the red star is located at the proximal end of the ascending colon.
The green star (on the descending colon) is located more distal on the colon, as it is further away from the point of origin or attachment of the colon.
More specifically, the green star is located at the distal end of the descending colon.
Anatomical Directional Terms: Examples of proximal and distal using the colon.
Summary of Proximal and Distal
Hopefully proximal and distal are more clear now.
Think of “proximal” and “proximity” to help you remember proximal is toward the trunk or point of origin/attachment.
Think of “distal” and “distant” to help you remember distal is away from the trunk or point of origin/attachment.
Superficial vs Deep
The next pair of directional terms is superficial and deep.
Superficial
If we move closer to the surface of the body, then we are moving superficial.
Therefore, superficial is defined as “closer to the surface”.
“Superficial” and “Surface” both start with the letter “S” which makes it easy to remember.
Anatomical Directional Terms: Labeled diagram showing superficial, defined as closer to the surface of the body.
Deep
If we move away from the surface of the body, then we are moving deep.
Therefore, deep is defined as “away from the surface of the body”.
The term is self-explanatory as we are moving deeper into the body.
Anatomical Directional Terms: Labeled diagram showing deep, defined as away from the surface of the body.
Examples of Superficial and Deep
Let’s look at examples of superficial and deep.
The skin is superficial to the ribs, as the skin is closer to the surface compared to the ribs.
The ribs are superficial to the lungs, as the ribs are closer to the surface of the body compared to the lungs.
Or you can say the lungs are deep to the ribs, as the lungs are farther away from the surface compared to the ribs.
The ribs are deep to the skin, as the ribs are farther away from the surface of the body compared to the skin.
Anatomical Directional Terms: Examples of superficial and deep using the skin, ribs, and lungs.
Summary of Superficial and Deep
Hopefully superficial and deep are easy to remember.
Superficial means closer to the surface of the body, and “Superficial” and “Surface” both start with the letter “S”.
Deep means away from the surface of the body, and you are moving “deeper” into the body.
Unilateral vs Bilateral
Next we have unilateral and bilateral.
Unilateral
Unilateral involves one side of the body.
For example, a patient could have a rash involving the right arm only as depicted by the star below.
The rash would be described as a unilateral rash involving the right upper extremity.
You might recall from the medical prefix lecture that “uni-” means one or single, which will help you remember unilateral involves one side of the body.
We know from above that lateral means “side or to the side”, so unilateral literally translates to “one side”.
Anatomical Directional Terms: Labeled diagram showing unilateral, defined as involving one side of the body.
Bilateral
Bilateral involves both sides of the body.
Now let’s say the patient has a rash involving both arms as depicted by the 2 stars below.
The rash would be described as a rash involving the bilateral upper extremities.
We learned in the medical prefix lecture that “bi-” means two or double, which will help you remember bilateral involves both sides of the body.
We know from above that lateral means “side or to the side”, so bilateral literally translates to “two sides”.
Anatomical Directional Terms: Labeled diagram showing bilateral, defined as involving both sides of the body.
Ipsilateral vs Contralateral
Finally, we have ipsilateral and contralateral.
Ipsilateral
Ipsilateral is defined as “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 below, then those injuries are ipsilateral to one another.
You might recall from the medical prefix lecture that “ipsi-” means same, which will help you remember ipsilateral means the same side of the body.
We know from above that lateral means “side or to the side”, so ipsilateral literally translates to “same side”.
Anatomical Directional Terms: Labeled diagram showing ipsilateral, defined as on the same side of the body.
Contralateral
Contralateral is defined as “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 lecture that “contra-” means opposite, which will help you remember contralateral means on opposite sides of the body.
We know from above that lateral means “side or to the side”, so contralateral literally translates to “opposite sides”.
Anatomical Directional Terms: Labeled diagram showing contralateral, defined as on opposite sides of the body.
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