It is of utmost importance to determine the existence of asymmetrical muscle tone in the body, and to locate the key dysfunction that causes this asymmetry.
Muscle tone is the continuous contraction of muscle, or resistance of muscle to passive stretch during resting state. It is modulated by the central nervous system. Normally, it should be the same on both the right and the left side of the body.
Asymmetry of muscle tone is the difference in tone between the two sides of the body. It is not about muscular tightness or weakness.
Normal
When the body in placed in a neutral resting position, the muscles on both sides exhibit the same tone. This is an indication of proper control of the brain on the muscles.
Abnormal
The muscles on one side of the body have a stronger tone, thus more resistance to passive stretch. This is a sign of imbalance output from the brain.
Balanced scales: Toby Hudson, Wikimedia Commons
Unbalanced scales: Toby Hudson, Wikimedia Commons
When proper stimulation is applied to the side of responsible dysfunction, the asymmetry of muscle tone will balance out, but the converse will happen if applied to the other side.
If it is the upper cervical is found to be the culprit, special neck X-ray is required for analyzing the misalignment.