22 Dance Anatomy and Kinesiology
movement. To aid with this understanding, it is first
important to remember that these planes are in ref-
erence to the body. So, if you turn the entire body,
these planes shift without any consideration for the
space in which you are standing. Hence, a parallel
back attitude would be in the sagittal plane whether
you were facing the front of the room, the side of the
room, or the front diagonal of the room. Second, it
is important to realize that with most joints key to
the study of human movement, motion involves rota-
tion of one bone relative to another bone (angular
motion). Because bones are secured relative to other
bones at joints, the bones rotate about this joint
when they receive force (see Muscles, Levers, and
Rotary Motion on p. 44 for more information). So,
to establish the plane of motion, picture the imagi-
nary surface that the entire rotating bone segment is
sweeping along. It sometimes helps to imagine that
you had chalk on that segment and then imagine
what plane the segment would “draw.” For example,
when you are standing in anatomical position and
lifting the thigh to the front and then back down,
the thigh segment “draws” a sagittal plane as seen in
figure 1.13. In contrast, when you are lifting the leg
to the side and then back down, the thigh segment
“draws” a frontal plane as seen in figure 1.14. Lastly,
when you are rotating the leg along the long axis of
the femur, the end of the leg (e.g., the foot) “draws”
a horizontal plane as seen in figure 1.16.Planes and Axes in Complex Movement
Understanding these three reference planes and associ-
ated axes is very helpful for analyzing movement. How-
ever, it is important to realize that joint axes are often
complex and involve subtle shifts in different ranges of
motions. Therefore, the concept of reference axes is
not exact but rather provides a useful approximation
helpful for picturing movement. Furthermore, many
complex dance movements utilize several planes with
different body segments and often involve planes
between the sagittal, frontal, and horizontal planes.
For example, aesthetics are often enhanced through
addition of rotation to the trunk when it is arched or
tilted rather than vertically positioned (figure 1.12).
Planes other than the basic sagittal, frontal, and
horizontal planes are termed diagonal, or oblique,
planes. In such cases the axis is perpendicular to the
particular diagonal plane and different from the
three reference axes previously described.Joint Movement Terminology
The movements at joints about the axes and in the
planes just described have specific names. Withthe exception of gliding joints, all synovial joints
can permit two or more of the following six basic
joint movements: flexion, extension, abduction,
adduction, external rotation, and internal rota-
tion. The logic of these terms is best seen relative
to anatomical position. As with position terminol-
ogy, these terms occur in pairs that have opposite
meanings. The pairings for movement terminology
are flexion-extension, abduction-adduction, and
external rotation-internal rotation. Each of these
pairs reflects movement that occurs in the same
plane and about the same axis, but in the opposite
direction. For example, flexion-extension could be
reflected by bringing the arm to the front (shoulder
flexion) or bringing the arm back (shoulder exten-
sion), with both movements occurring in the sagit-
tal plane about an ML axis. A description of these
fundamental movements follows, and a summary is
provided in table 1.8.- Flexion (L. flecto, to bend) involves bringing
anterior surfaces toward adjacent anterior surfaces,
or posterior surfaces toward adjacent posterior sur-
FIGURE 1.12 Dance vocabulary showing movement of
the trunk that does not occur in the basic planes, but
rather in diagonal planes.
CSULB dancer Jennifer Fitzgerald.