50 Yoga anatomY
Spinal Joint actions
The following terms describe movements when the joints of the spine are moving and the
vertebrae articulate in relationship to each other. In these spinal actions the actual shape
of the spine changes, which is a different action than moving the spine through space (by
articulating at the hips, for example, which would be an action in the legs). Common yoga
language such as forward bending is a nonanatomical description that can refer to either
a movement of the spine through space or the spinal joint action of flexion (see chapter
2, page 33).
flexion—Movement in the sagittal plane that brings the anterior surfaces of the body
toward each other.
extension—Movement in the sagittal plane that brings the anterior surfaces of the
body away from each other.
lateral flexion—Movement in the vertical or coronal plane that bends the spine to
one side or the other.
rotation—Movement in the horizontal or transverse plane, around the vertical axis
of the spine:- In rolling, all of the parts of the spine rotate in the same direction.
- In twisting, one part of the spine turns a different direction from another part of
the spine.
axial extension—Movement along the vertical axis of the spine that lengthens the
spine by taking out the sagittal curves.
circumduction—Movement that travels through space around the axis of the body,
tracing a cone shape. This is not the same as rotation.limb Joint actions
These terms describe the joint actions that can happen in the upper and lower limbs, which
include the shoulder girdle and pelvis. As in the spine, there is a difference between moving
a joint through space and actually articulating in the joint, which is the joint action. (For
example, when you lift your whole arm to the ceiling, the elbow does move through space
but it doesn’t necessarily articulate.)
actions in all limbs
For the joint actions below, the same terms can be used to describe movement at a variety of
joints. Which bones are involved in the movement will depend on which joint is articulating.
flexion—Movement in which the anterior surfaces of the limb move toward each
other; depending on the position of the spine, hips, and shoulders, this could happen
in any plane. Because of a spiral in the limbs that occurs while we are embryos, flexion
in the knee, ankle, and foot joints moves what we consider the back surfaces of the
leg toward each other.
extension—Movement in which the anterior surfaces move away from each other;
again, depending on the position of the spine, hips, and shoulders, this could happen in
any plane. And, because of that embryological spiral, extension in the knee, ankle, and
foot joints moves what we consider the back surfaces of the leg away from each other.