Directional terms serve to describe position of structures relative to other structures: an organ described as rostral is closer to the head, whereas a caudal organ is closer in proximity to the feet.
Anatomical terms can be combined to more precisely describe the location of an organ or a region. For example, one might say that the right chest muscle, also called the pectoralis major, is anterolateral to the breastbone, also known as the sternum. This indicates that the right chest muscle is both anterior and lateral to the breast bone. But when relating the right shoulder to the right chest muscle, the appropriate directional term becomes superolateral because the shoulder is above, or superior to, and lateral to the right chest muscle. Directional terms are chosen based on the organs or regions being examined as they relate to each other.
Common Directional Terms
| Term | Meaning | Example |
|---|---|---|
| anterior | front, toward the front | The breastbone is anterior; the spinal column is posterior. |
| posterior | back, toward the back | |
| distal | farther from the point of origin | The elbow is proximal to the shoulder; the wrist is distal to the shoulder. |
| proximal | closer to the point of origin | |
| dorsal | the back surface | Surgery on the spine requires a dorsal approach; surgery to remove an appendix requires a ventral approach. |
| ventral | the front surface/belly | |
| superior | located above or over | The heart is superior to the stomach; the intestines are inferior to the stomach. |
| inferior | located below or underneath | |
| lateral | the side, moving away from the midline | Lateral to the eye is the ear; medial to the eye is the nose. |
| medial | moving toward the midline away from the side | |
| cephalic (cranial) | in relation to the head, toward the head | A baby in the cephalic presentation is born head first; within the skull, the frontal lobe of the brain is rostral while the occipital lobe is caudal. |
| rostral | in relation to the front end, toward the nasal/oral region | |
| caudal | in relation to the back or tail end | |
| bilateral | both sides | Bilateral fractures are bone fractures on both sides of the body; a unilateral fracture is a broken bone that has occurred on one side only. |
| unilateral | one side | |
| ipsilateral | on the same side | The right elbow is ipsilateral to the right wrist but contralateral to the left elbow. |
| contralateral | on opposite sides | |
| parietal | refers to body cavity wall | The parietal pleura is the membrane lining the cavity where the lungs are located; the visceral pleura is the membrane lining the lungs. |
| visceral | refers to organs within body cavity | |
| axial | relating to the central part of the body | The axial skeleton consists of the head, neck, and trunk; the appendicular skeleton consists of the limbs (arms and legs). |
| appendicular | relating to the limbs | |
| superficial | close to the surface | A superficial wound injures the outer portion of the skin; a deep wound penetrates skin, fat, tissue, and muscle. |
| deep | farther from the surface |