Directional Terms & Regional Terms
Anatomists and health care providers use medical terminology that can difficult and esoteric. However, the purpose of this language is to increase accuracy and reduce the chance for medical errors. For example, is an injury “above the wrist” located on the forearm two or three inches away from the hand or at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. Many of these terms are derive from ancient Greek and Latin words since the meaning of their words are universal and do not change.
To increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the 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. Using this standard position reduces since the anatomical terms are independent of the body’s orientated.
TL; DR
- 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 Terms
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 | Origin | Meaning |
Example |
|---|---|---|---|
| Superior | super- (latin) | above | Head is superior to the chest. |
| Inferior | inferus (Latin) |
low; below |
Pelvis is inferior to the chest. |
| Ventral | venter (Latin) |
belly; underside | Abdomen is on the ventral side of our body. |
| Dorsal | dorsum (Latin) |
back | Spine is on the dorsal side of our body. |
| Anterior | ante (Latin) |
before; in front |
|
| Posterior | post (Lain) |
behind | |
| Superficial | super- (Latin) facies (Latin) |
"above face"; outer surface |
Skin is a superficial organ |
| Deep | Below the skin are deep tissues. |
||
| Rostral |
rostrum (Latin) |
break; toward the |
Our forehead is rostral to the top of our head. |
| Cranial | cranium (Latin) kranion (Greek) |
skull; towards the head |
Cervical vertebrae are most cranial. |
| Caudal | cauda (Latin) |
tail; toward the |
Tailbone is the most caudal vertebrae. |
| Lateral | later- (Latin) |
side; toward the |
The sides of our body are lateral. |
| Medial | medius (Latin) |
middle; towards the |
Sternum (brestbone) is medial |
| Proximal | proximus (Latin) |
nearest; closer to origin |
The proximal forearm is closer to the elbow. |
| Distal | dis- (Latin) |
apart; further from origin |
The distal forearm is closer 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?
Is there a differnce between ventral and anterior or dorsal and 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.
Regional Terms
References
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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. License: CC BY 4.0 | License Terms: Edited & Adapted | Access for free https://openstax.org/books/anatomy-and-physiology/pages/1-introduction.