Dance Anatomy & Kinesiology

28 Dance Anatomy and Kinesiology

that “P” in pointing goes with “P” in plantar flexion.

These movements occur in the sagittal plane around

an ML axis as seen in figure 1.13. Additional spe-

cialized terminology for both the upper and lower

extremity is addressed in chapters covering the

respective joints.

Joint Movements Associated

With Specific Types of Synovial Joints

Now that planes, axes, and joint movement termi-

nology have been covered, the movement capacity

of synovial joints can be added to their shape-based

description. Synovial joints can be subclassified

according to whether they have one, two, three, or

no axes—uniaxial, biaxial, triaxial, and nonaxial,

respectively. The number of axes a joint has also

parallels the number of planes in which that joint

allows motion, which is termed degrees of freedom

(df) and determines the types of movement allowed

from anatomical position.

Gliding joints are considered nonaxial joints as

they allow only slight gliding or sliding motion that

does not occur about an axis. Hinge and pivot joints

are uniaxial joints allowing movement in one plane

(1df). Hinge joints allow the movements of flexion-

extension in the sagittal plane, while pivot joints

allow rotation in the horizontal plane. Condyloid and

saddle joints are biaxial joints allowing movement in

two planes (2df). Condyloid joints generally allow

flexion-extension in the sagittal plane and abduction-

adduction in the frontal plane (although specialized

terminology is used for some of these movements).

For the saddle joint (first carpometacarpal joint),

specialized movement terminology is used that will

be addressed in chapter 7. The ball-and-socket joint

is the only type of triaxial joint, allowing move-

ment in three planes (3df). Movements allowed

are flexion-extension in the sagittal plane, abduc-

tion-adduction in the frontal plane, and external

rotation-internal rotation in the horizontal plane.

Notice that triaxial joints differ from biaxial joints

through the addition of rotation. The association of

movement capacity and joint type is summarized in

table 1.4 (p. 16).

Skeletal Considerations in Whole Body Movement.

Additional concepts come into play when one

examines the contribution of bones and joints to

functional movements such as those used in danc-

ing. Three particularly key considerations are joint

stability and mobility, close-packed and loose-packed

positions of joints, and closed and open kinematic

chain movements.

Types of Synovial Joints and Their Movements

While standing in anatomical position, identify the following joints and perform their movements. Refer

to figure 1.9 as needed.

• Uniaxial joints. Perform the movements of the forearm that are allowed by the elbow joint. What
  type of synovial joint is it? In what plane and about what axis does movement of this joint occur? Now,
  perform movements of the forearm that are allowed by the upper radioulnar joint. In what plane and
  about what axis does movement of this joint occur?


• Biaxial joints. Perform the movements of the hand that are allowed by the wrist joint. What type
  of synovial joint is it? In what two planes and about what two axes does movement of this joint occur?
  Now, perform movements of the thumb and note similarities and differences from the wrist joint. Can
  either of these joints be actively rotated?


• Triaxial joints. Perform the movements of the upper arm that are allowed by the shoulder joint.
  What type of synovial joint is it? In what three planes and about what three axes does movement
  of this joint occur? How does rotation differ from circumduction? What plane is utilized with triaxial
  joints that is missing with biaxial joints? How does this combination of uniaxial, biaxial, and triaxial
  joints further the stability and mobility demands of the upper extremity in gestural movements and
  weight-bearing movements in dance?

CONCEPT DEMONSTRATION 1.2