Understanding Anatomical Terms For Location And Relative Position
If you work with students or clients in a body-centered practice like yoga, Pilates, physical therapy, or personal training, then you know how important it is to be able to communicate about what you see and feel in someone’s body. For that reason, anatomists, medical practitioners, and others have developed a shared anatomical language to describe the location and relative position of structures in the body. This terminology helps us be specific and consistent about what we’re describing.
Bodies are complicated. Using agreed upon anatomical terms helps us be clear in our communication about the complexity we’re describing. In this article, I’ll take you on a tour of the anatomical terms used to describe the location and relative position of structures in the body.
Describing position and location in the body
When we use positional anatomical terms, we commonly use them in one of two ways. We might refer to something in the body by its general location, for example on the front of the body. The other way we reference structures in the body is by describing their position relative to something else. For example, we might refer to a muscle as being above, below, underneath, or on top of another muscle. Keep that in mind as we walk through common anatomical terms for position and how we often use them.
Additionally, sometimes there is more than one set of anatomical terms to describe particular positions and locations. Where there is more than one set of terms for a position in the body, we’ll discuss both.
Anatomical terms for position and location
Superior and inferior
The first set of terms we’ll discuss are anatomical terms for structures that are above or below another structure. We have two sets of terms we can use to describe parts of the body that are above or below something else. The term superior refers to something that is above something else. Inferior means that something is below something else.
Cranial and caudal
We have a second set of anatomical terms that aren't used quite as often but have a similar meaning to superior and inferior. We can also use the terms cranial and caudal to describe the relative position of structures that are above or below something in the body. Something that is cranial means it is toward the head compared to another structure.
Something that is caudal means it is towards your “tail,” or away from your head, which in the case of a human in anatomical position would be closer to your feet. Because we are describing the location of structures from anatomical position, something that is above something else would also be closer to the head. A structure that is below another structure would also be closer to the feet.
If we know the roots of these anatomical words, the meanings of the roots of these words can help us potentially understand and remember the anatomical terms. Cranial is related to the word cranium which you probably already know refers to the skull. So it makes sense that something that is in the cranial direction is something closer to the skull or head. Caudal is related to the word cauda which means tail. So, likewise, it makes sense that something that is in the caudal direction is closer to the tail.
Lateral and medial
The next set of anatomical terms we’ll look at involve describing the position of structures in relation to the midline of the body. If we draw a line from the top of our head to our feet that bisects the body into a right and left side in the sagittal plane, that is referred to as the midline of the body. Something that is closer to that midline positionally is referred to as more medial. Something farther from that midline or closer to the outside of the body is referred to as more lateral.
Internal and external
The terms internal and external are similar to the terms lateral and medial. The terms internal and external are used interchangeably with lateral and medial when we are describing a direction of movement. Movement such as rotation in the medial direction, describes movement that is going internally, or closer to the midline (inside) of the body. Movement in a lateral direction is movement externally, away from the center of the body, or towards the outside of the body. However, when we refer to a position of a structure, rather than a movement, we typically use the words lateral and medial.
Anterior, posterior, ventral, and dorsal
If we divide our body into a front and back half in the coronal plane, this is where we apply the anatomical terms anterior and posterior. A structure that is more anterior is closer to the front of the body. Something that is more posterior is closer to the back of the body. Additionally, there is another set of terms that are used similarly to anterior and posterior, but are used less often. Those terms are ventral and dorsal. Ventral, like the term anterior, is used to refer to a structure that is on the front of the body. Dorsal is similar to posterior and refers to a structure that is on the back of the body.
Distal and proximal
The next two terms, distal and proximal, are primarily used to describe only the relative position of structures on the appendicular skeleton in relation to their distance from the axial skeleton. Remember that the appendicular skeleton includes arms, legs, shoulder girdle, and pelvic girdle. The rest of your skeleton, including the spine, ribcage, head, and neck, is considered the axial skeleton.
Distal is used to describe a structure on the appendicular skeleton that is farther away from the axial skeleton than something else (on the appendicular skeletal system). The term proximal is used to describe a structure that is closer to the axial skeleton than something else (on the appendicular skeletal system). For example, we could say that our fingers are distal to our elbow because they are farther away from the rest of our body (our axial skeleton) than our elbow.
Ipsilateral and contralateral
Ipsilateral and contralateral are two frequently confused words for the position of body structures. If we break down the roots of these two words it can help us understand their meaning. The prefix “ipsi” means the same. The prefix “contra” means opposite or against. Lateral means the side of something. So these are anatomical terms that describe whether something is located on, or happening on, the same side or opposite side as something else.
These words can be used to describe relative position in the body or relative movement. For example, I could say my internal oblique muscles run from my iliac crest and inguinal ligament to my ipsilateral lower ribs because the internal oblique muscle travels between these attachments on the same side of the body. If I’m using these words to describe movement, I could say that when we walk, as we step with the right foot, our contralateral arm swings forward at the same time. We would use the word contralateral to describe that movement in gait because it is our opposite arm that swings forward when we take a step.
Superficial and deep
The anatomical terms superficial and deep describe the depth at which something is found in the body. Another way to say that is that these terms describe how close to the surface of the body something is relative to something else. Superficial refers to a structure that is closer to the surface of the body. Deep refers to a structure that is farther away from the body’s surface. For example, I could say my skin is superficial to my biceps brachii muscle. Or, I could compare the depth of two muscles. For example, the brachialis muscle is deep to (underneath) the biceps brachii muscle.
Supine and prone
The terms supine and prone are a little different from the terms I’ve explained so far. These two terms describe the position of the whole body in space. Supine is the anatomical term to describe lying face up. Prone is the anatomical term to describe lying face down.
Conclusion
The body is complex. An important part of learning about the body including the study of kinesiology is being able to communicate clearly what we see. Anatomical terms help us do that. Anatomical terms for position help us use precise language to describe where structures are located in the body and how they are positioned in relation to the front, back, top, bottom, inside, and outside of the body, as well as how they are positioned in relation to other structures.