Download directional terms - Blue Valley Schools

DIRECTIONAL TERMS
Directional terms are used to describe the positions of structures on the body relative to other structures
or locations. Each directional term usually has a partner term with an opposing meaning.
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Anterior (or Cranial) means the structure is closer to the head of the animal.
Posterior (or Caudal) indicates that the structure being described is closer to the tail.
For structures on the head, rostral means the structure is closer to the nose, and caudal
means the structure is closer to the back of the head.
Medial means the structure is closer to the midline of the limb, trunk, or head.
Lateral indicates the structure is farther away from the midline
Dorsal means the structure is closer to the top side (back) of the animal.
Ventral means the structure is closer to the bottom side (belly) of the animal.
Pectoral refers to the chest region or the area supported by the forelegs.
Pelvic refers to the hip region, or the area supported by the hind legs.
PLANES OF SYMMETRY (for bilaterally symmetrical animals)
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transverse plane
o divides head and trunk into anterior and posterior halves
o divides an appendage into proximal and distal portions
o perpendicular to long axis
frontal plane
o divides the head or trunk into dorsal and ventral portions
o parallel to the long axis
median plane
o divides body part into right and left sections
o parallel to the long axis
ASSIGNMENT: Draw a diagram (or diagrams) illustrating the three planes of symmetry using a bilaterally
symmetrical animal of your choice. Be sure to label the three different planes.