Terms of position

The body usually lies horizontally on a table dur￾ing dissection, but the dissector must remember
that terms describing positions are always used as
though the body is in the anatomical position.
In this position, the person is standing upright,
with the upper limbs by the sides and palms of the
hands directed forwards.
Descriptive terms are used to indicate the position
of structures as if the body were in the anatomical
position [Fig. 1.1]. Superior or cephalic refers to
the position of a part that is nearer the head, while
inferior means nearer the feet. Caudal (towards
the tail) can replace inferior in the trunk. Anterior
means nearer the front of the body, and posterior
means nearer the back. Ventral and dorsal may
be used instead of anterior and posterior in the
trunk and have the advantage of being appropriate
also for four-legged animals (venter = belly; dorsum =
back). In the hand, dorsal commonly replaces

posterior, and palmar replaces anterior. In the
foot, the corresponding surfaces are superior and
inferior in the anatomical position, but these terms
are usually replaced by dorsal (dorsum of the
foot) and plantar (planta = the sole).
Median means in the middle. Thus, the median
plane is an imaginary plane that divides the body
into two equal halves, right and left. Where the me￾dian plane meets the anterior and posterior surfaces
of the body are the anterior and posterior medi￾an lines. A structure is said to be median when it is
bisected by the median plane. Medial means nearer
the median plane, and lateral means further away
from that plane. The presence of two bones, one
lateral and the other medial, in the forearm (radius
and ulna) and leg (fibula and tibia) have resulted in
the terms ulnar or radial side of the forearm, and
tibial or fibular side of the leg. The words outer
and inner, or their equivalents external and inter￾nal, are used only in the sense of nearer the surface
or further away from it in any direction; they are not
synonymous with medial and lateral. Superficial,
meaning nearer the skin, and deep, meaning fur￾ther from it, are the terms most usually used when
direction is of no importance. When describing the
surfaces of a hollow organ, external refers to the
outer surface, and internal to the inner surface.
A sagittal plane may pass through any part of
the body, parallel to the median plane. A coronal
plane is a vertical plane at right angle to the me￾dian plane. A transverse plane is a horizontal plane
(perpendicular to both the above). All other planes
are oblique planes.
Proximal (nearer to) and distal (further from)
indicate the relative distances of structures from
the root of that structure, e.g. the relative distance

of the elbow from the root of the upper limb.
Middle, or its Latin equivalent medius, is used to
indicate a position between superior and inferior
or between anterior and posterior. Intermediate
is used to indicate a position between lateral and
medialThe terms superolateral and inferomedial,
or anteroinferior and posterosuperior, or any
other combination of the standard terms, may be
used to show intermediate positions
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