Directional terms come in opposing pairs (like East/West and North/South). Anatomical directional terms are used to describe relative position consistently within a cadaver, independent of how the cadaver is oriented in the East/West, North/South world.
Dorsal/Ventral:
Dorsal -- directed toward the back[head, trunk, tail]; also applied to manus & pes.
Ventral -- directed toward the belly [head, trunk, tail].
Medial/Lateral:
Medial -- directed toward the midline (median plane) [head, trunk, tail, & limbs].
Lateral -- directed away from the median plane, toward the flank [head, trunk, tail, & limbs].
Cranial/Caudal:
Cranial -- directed toward the cranium (brain case) [trunk, tail, limbs].
Caudal -- directed toward the tail (& beyond) [head, trunk, tail, limbs].
Rostral/Caudal:
Rostral -- directed toward the nose (beak) [head].
Caudal -- directed toward the tail (& beyond) [head, trunk, tail, limbs].
Proximal/Distal:
Proximal -- directed toward the body [limbs & tail].
Distal -- directed away from the body [limbs & tail].
Anatomical planes are used to describe cuts made through a cadaver in order to view structures exposed by the cut. While a very large number of possible cuts could be made through a particular cadaver, three orthogonal (at right angles to one another) planes are most important. (Limbs are usually cut (transected) in only one plane, perpendicular to their long axis.)
Dorsal Plane:
A Dorsal Plane is parallel to the back [head, trunk, tail].
Transverse Plane:
A Transverse Plane is perpendicular to the tong axis of the body [head, trunk, tail].
Sagittal Plane:
A Sagittal Plane divides the body into right/left parts [head, trunk, tail].
Median Plane:
The Median Plane is a mid-sagittal plane that divides the body into left/right halves [head, trunk, tail].
Limb Transections:
Limbs are generally cut by planes that are transeverse relative to the long axis of the limb [limbs].
Muscles act by moving joints. Thus, the same terms apply to both muscle actions and joint movements. All joint movements are described by opposing terms (directions). One set of muscles moves a joint in one direction; another set of muscles moves the same joint in the opposite direction. Most joints in the body function as "hinge" joints, meaning they move (extend/flex) in one plane. Ball and socket joints (e.g., the hip joint) are capable of circumduction (circular motion). Limbs as a whole are capable of rotation (supination/pronation) and movement away from (abduction) and toward (adduction) the body.
Extension/Flexion:
Extend -- increase the angle formed by a hinge joint.
Flex -- decrease the angle formed by a hinge joint.
Abduction/Adduction:
Abduct -- move the limb away from the body.
Adduct -- move the limb toward the body.
Supination/Pronation:
Supinate -- rotate the limb so the dorsum of the manus (or pes) is directed laterally.
Pronate -- rotate the limb so the dorsum of the manus (or pes) is directed medially.
This web page can be downloaded to your local hard disk. Click the FTP link (below) to download Anatomy Directions & Planes. Your browser will list an "anatDirections" folder. On a PC, right-button click the anatDirections folder and choose "copy to..." from the pop-up menu in order to copy the folder to your target location on your local hard disk. On a Mac, control click "anatDirections" and choose "Download ..." from the pop-up menu, or just drag "anatDirections" to your desktop.
On your local hard disk, open the "anatDirections" folder and locate the file "Begin.html". Start by opening Begin.html in you browser, either by double-clicking the file or choosing open file from the browser menu. (Your browser must have a Flash plug-in to view the illustrations and animations of this web site.)
Primary Site for FTP Download
Click to initiate download of Anatomy Directions & Planes.
