Directional Terms & Regional Terms
Have you ever been trying to get somewhere following directions that have left and right in the instructions? While you may have gotten to your destination, you may also think, that left or right are not really universal directions; left or right really depends on your orientation. For this reason, it’s sometimes easier to navigate using the cardinal points (north, south, east, west) because they aren’t dependent on your orientation. East is always east, even if your facing south!
For this same reason is why we using universal set of terms to describe direction and region in anatomy. It may not seem like a big deal, but these terms are used so we can be more specific when describing something and to potentially reduce medical error. Many of these terms are derived from ancient Greek and Latin words. Because these languages are no longer used in everyday conversation, the meaning of their words does not change.
- → Directional and regional terms are used in anatomy to precisely describe specific locations.
- → Many of these terms were chosen from Greek and Latin root words.
Directional anatomical terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. These terms usually come in pairs, with one word meaning a specific direction and the paired word meaning the opposite. Let’s take a look at some common directional terms:
|Directional Term||Common Term||Example|
|Superior||above; higher||Chest is superior to the abdomen.|
|Inferior||below; lower||Heart is inferior to the brain.|
|Ventral||belly; underside||Our abdomen is on the ventral side of our body.|
|Dorsal||towards the spine||Our spine is the dorsal side of our body.|
|Anterior||front||Our eyes, nose and mouth are on the anterior side of our head.|
|Posterior||back; behind||Shoulder blade would be consideredposterior.|
|Superfical||towards the surface||Skin is a superficial organ.|
|Deep||away from the surface||Below the skin are deep tissues.|
|Caudal||towards the 'tail'||The coccyx is the most caudal vertebrae in our spine.|
|Cranial||towards the head|
|Lateral||outer||Ears and shoulders would be consider lateral.|
|Medial||towards the middle/ midline||Our sternum/brestbone would be a considered medial.|
|Proximal||closer to point of attachment or trunk||The elbow proximal to the wrist.|
|Distal||further from point of attachment or trunk||Fingers are distal to the wrist|
You may have noticed that these terms are always communicating a position or direction relative to something else. For example, your abdomen would be superior if relative to your legs, but inferior relative to your chest. More commonly, the terms are used to locate a specific locations within the same area – or on the same bone. Let’s consider your upper arm. If we were to referring to a location of your upper arm as superior, do you think that would mean closer to the armpit, or closer to the elbow?
The difference between ventral/dorsal and anterior/posterior
For two legged animals, the answer is pretty straightforward: not much. Since the front of our body is also the ‘bellyside,’ there used somewhat interchangably. Likewise for our back (posterior) and ‘spine side’ (dorsal). However, for four legged animals, this isn’t the case.
Just as maps are normally oriented with north at the top, the standard “body map” is that of a body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward. Using this standard position reduces confusion since it does not matter how the body being described is oriented. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.
|Regional Term||Common Name|
|Antecubital||elbow (ventral side)|
|Carpal||wrist (small bones)|
|Cervical||neck; (also cervix)|
|Digital||fingers and toes|
|Occipital||back, base of head|
|Olecranal||point of elbow|
|Sacral||related to the sacrum|
|Tarsal||ankle (small bones|
- Betts, J. Gordon, et al. “1.6 Anatomical Terminology.” Anatomy and Physiology, OpenStax, https://openstax.org/books/anatomy-and-physiology/pages/1-6-anatomical-terminology.*Some of the text and images on this page were shared directly from OpenStax under the creative commons license CC by-sa 3.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction