Directional terms let anyone describe where something is without confusion. They all assume anatomical position: standing, facing forward, arms at the sides, palms facing forward.
Terms come in opposite pairs
| Term | Means | Opposite | Means |
|---|---|---|---|
| anterior (ventral) | front | posterior (dorsal) | back |
| superior (cranial) | toward the head | inferior (caudal) | toward the feet |
| medial | toward the midline | lateral | away from the midline |
| proximal | closer to the trunk | distal | farther from the trunk |
| superficial | toward the surface | deep | away from the surface |
Proximal and distal are for limbs: the shoulder is proximal to the elbow, the fingers are distal to the wrist. Think proximity: close.
Why the palms face forward
It settles questions like where the thumb is. With palms forward, the thumb is lateral and the little finger is medial. In the forearm, that's why the radius (thumb side) is lateral to the ulna.
Body planes
- Sagittal: left and right (midsagittal makes equal halves).
- Frontal (coronal): front and back.
- Transverse (horizontal): top and bottom. This is the “slice” a CT scan usually shows.
Movement pairs
- Flexion makes a joint's angle smaller (bending the elbow); extension straightens it.
- Abduction moves a limb away from the midline; adduction brings it back. Ab- means away, as in abduct.
Lying down
Supine is face up (on your spine); prone is face down.
Education only, not medical advice.