A leg length difference can be an indication of imbalance tone in your body’s musculature and therefore is one of our objective measures to determine whether or not you are in need of an adjustment. After an adjustment we will often check leg-length again and find that legs to be of balanced length.
There are many postural muscles that are constantly contracting and relaxing in response to normal body movements to prevent us from falling over and allow us to maintain an upright posture. When our first vertebra is misaligned, the weight of the head is no longer evenly distributed over the neck and the rest of the body. The body therefore reflexively responds to this imbalance by contracting different postural muscles in its attempt to maintain an upright posture. It is the reflexive contractions of the postural muscles that result in the contracted/ shortened leg.