Anatomical directional terms are like the directions on a compass rose of a map. Like the directions North, South, East and West, they can be used to describe the locations of structures in relation to other structures or locations in the body. This is particularly useful when studying anatomy as it provides a common method of communication that helps to avoid confusion when identifying structures.
Also as with a compass rose, each directional term often has a counterpart with converse or opposite meaning. These terms are very useful when describing the locations of structures to be studied in dissections.
Anatomical directional terms can also be applied to the planes of the body. Body planes are used to describe specific sections or regions of the body. Below are examples of some commonly used anatomical directional terms and planes of the body.
Anterior: In front of, front
Axial: Around a central axis
Bilateral: Involving both sides of the body
Caudal: Toward the back, toward the tail
Contralateral: On opposite sides of the body
Distal: Away from, farther from the origin
Dorsal: Near the upper surface, toward the back
Inferior: Below, under
Intermediate: Between two structures
Ipsilateral: On the same side of the body
Lateral: Toward the side, away from the mid-line
Medial: Toward the mid-line, middle, away from the side
Parietal: Relating to a body cavity wall
Posterior: After, behind, following, toward the rear
Proximal: Near, closer to the origin
Rostral: Toward the front
Superior: Above, over
Unilateral: Involving one side of the body
Ventral: Toward the bottom, toward the belly
Visceral: Relating to organs within body cavities
Imagine a person standing in an upright position. Now imagine dissecting this person with imaginary vertical and horizontal planes. This is the best way to describe anatomical planes. Anatomical planes can be used to describe any body part or an entire body.
Frontal Plane or Coronal Plane: Imagine a vertical plane that runs through the center of your body from side to side. This plane divides the body into front (anterior) and back (posterior) regions.
Lateral Plane or Sagittal Plane: Imagine a vertical plane that runs through your body from front to back or back to front. This plane divides the body into right and left regions.
Transverse Plane: Imagine a horizontal plane that runs through the midsection of your body. This plane divides the body into upper (superior) and lower (inferior) regions.
Some anatomical structures contain anatomical terms in their names that help identify their position in relation to other body structures or divisions within the same structure. Some examples include the anterior and posterior pituitary, superior and inferior venae cavae, the median cerebral artery, and the axial skeleton.
Affixes (word parts that are attached to base words) are also useful in describing the position of anatomical structures. These prefixes and suffixes give us hints about the locations of body structures. For example, the prefix (para-) means near or within. The parathyroid glands are located on the posterior side of the thyroid. The prefix epi- means upper or outermost. The epidermis is the outermost skin layer. The prefix (ad-) means near, next to, or toward. The adrenal glands are located atop the kidneys.
Understanding anatomical directional terms and body planes will make it easier to study anatomy. It will help you to be able to visualize positional and spatial locations of structures and navigate directionally from one area to another. Another strategy that can be employed to help you visualize anatomical structures and their positions is to use study aids such as anatomy coloring books and flashcards. Coloring books and review cards can really help you visually comprehend information.