Dance Anatomy & Kinesiology

26 Dance Anatomy and Kinesiology

the dancer performs a circling motion with the foot on

the floor (circular portion of rond de jambe à terre).

• Internal rotation is the opposite motion to exter-
  nal rotation, although still in the horizontal plane and
  about a longitudinal axis through the body segment as
  seen in figure 1.16. Internal rotation involves bringing
  the anterior surface of the limb inward, toward the
  midline of the body, such as is used in jazz dance when
  the thigh is rotated inward so that the knee faces medi-
  ally. It is also termed medial or inward rotation. Unlike
  what occurs with some of the other movement pairs
  discussed, the limb can readily be either internally
  or externally rotated from anatomical position, and
  anatomical position is often regarded as the neutral
  position. External-internal rotation occurs in some
  uniaxial (pivot) joints and all triaxial (ball-and-socket)
  joints. External rotation-internal rotation occurs at
  such joints as the shoulder and hip.

Specialized Joint Movement Terminology

At some joints, additional terminology is used to

describe motions. This specialized terminology is

usually used for certain joints in an effort to clarify

the direction of movement or to describe movement

that is slightly different from the six basic movements

just discussed. For example, since the midline runs

through the head and trunk segments, much of the

basic terminology does not work well for describing

movements of the spine. Hence, during bending

the torso to the side in the frontal plane, abduction-

adduction does not clearly describe what is occur-

ring, and right or left lateral flexion is alternatively

used. So, right lateral flexion is the movement of

bending the torso to the right, while returning from

this position to anatomical position or bending to

the left is termed left lateral flexion as seen in figure

1.14. Similarly, external and internal rotation in the

transverse plane are not adequate characterizations

for the spine or head, and rotation is described as

right or left rotation from the perspective of the

dancer who is moving. So, right rotation is movement

of the anterior surface of the head or trunk so that

it faces right, while left rotation is movement of the

anterior surface of the head or trunk so that it faces

left as seen in figure 1.16.

FIGURE 1.16 Joint movements in the horizontal plane about a vertical axis: internal rotation-external rotation, pronation-

supination, right rotation-left rotation, and horizontal abduction-adduction.