12
UNIT 1
Organization of the Body
1
Table 1.1
Orientation and Directional Terms
TERM
DEFINITION
EXAMPLE
 
Superior (cranial)
Toward the head end or upper
part of a structure or the body;
above
 
The head is superior to the abdomen.
Inferior (caudal)
Away from the head end or
toward the lower part of a
structure or the body; below
 
The navel is inferior to the chin.
Ventral (anterior)*
Toward or at the front of the
body; in front of
 
The breastbone is anterior to the spine.
Dorsal (posterior)*
Toward or at the back of the
body; behind
 
The heart is posterior to the breastbone.
Medial
Toward or at the midline of the
body; on the inner side of
 
The heart is medial to the arm.
Lateral
Away from the midline of the
body; on the outer side of
 
The arms are lateral to the chest.
Intermediate
Between a more medial and a
more lateral structure
 
The collarbone is intermediate between
the breastbone and shoulder.
Proximal
Closer to the origin of the body
part or the point of attachment of
a limb to the body trunk
 
The elbow is proximal to the wrist.
Distal
Farther from the origin of a body
part or the point of attachment of
a limb to the body trunk
 
The knee is distal to the thigh.
Superficial (external)
Toward or at the body surface
 
The skin is superficial to the skeletal
muscles.
Deep (internal)
Away from the body surface;
more internal
 
The lungs are deep to the skin.
*The terms
ventral
and
anterior
are synonymous in humans, but this is not the case in four-legged animals.
Anterior
refers to the leading portion of the
body (abdominal surface in humans, head in a cat), but
ventral
specifically refers to the “belly” of a vertebrate animal, so it is the inferior surface of four-
legged animals. Likewise, although the dorsal and posterior surfaces are the same in humans, the term
dorsal
specifically refers to an animal’s back. Thus,
the dorsal surface of four-legged animals is their superior surface.
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