Introduction to Anatomy
The study of anatomy has a language all its own. The terms have evolved over many centuries. Most students think anatomical terms are hard to remember and pronounce and, in some cases, they are. In any event, you must learn and understand the terms that apply to the anatomical structures of dental interest and you must be familiar with oral and dental anatomy.
General Reference Terms
Anterior and Posterior. Anterior and posterior describe the front-to-back relationship of one part of the body to another. For example, the ear is posterior to (in back of) the eye, the nose is anterior to (in front of) the ear, etc.
Internal (Medial) and External (Lateral). The words internal and medial are synonyms, so are external and lateral. These two terms describe the sideways relationship of one part of the body to another using the midsagittal plane (see definition below) as a reference. For example, the ear is external (or lateral) to the eye because the ear is further from the midsagittal plane; the eye is internal (or medial) to the ear because it is closer to the midsagittal plane.
Long Axis. The longitudinal center line of the body or any of its parts.