Thomas E. Sabalaske DO
There is a lot more to posture than your mother correcting you to sit up straight.  The
vertebral spine has naturally occurring curves that provide shock absorption and the
ability to remain upright with little energy expenditure.  Posture is a complex world
where a strong majority of the activities are in front you.  There is a usual pattern of
people being stronger (and tighter) in the anterior of their torso and weaker in some
of the important muscular groups of the upper back.  

To simplify the problem, if your big heavy head is not well balanced on top of your
cervical spine and hanging a bit in front of your neck, then gravity will try to pull it to
the ground.  To counteract this, your body uses its upper back musculature
(trapezius, levator scapulae etc.) to pull the head closer back to on top of the body.  
This in turn leads to chronic neck, upper back and shoulder tension.

In addition to physiological forces, there are psychological and social factors which
may further discourage a person from keeping his/her head held high such as a
desire to avoid interpersonal contact or a lack of self esteem. The epidemic of poorly
managed stress initiates a posture response to curl up into the fetal position, again
opposing the natural curvatures of the spine that are crucial for good posture.

Correction to functionally balanced posture often includes:  loosening the anterior
soft tissues of the chest and torso that are pulling the neck and head forward,
strengthening some of the upper back musculature to pull the shoulders and neck
back and away from the anterior head carriage, strengthening the core musculature
and gluteal muscles to provide stabilization during the gait (walking) cycle, and
correcting dysfunctions that hinder any of the above situations with osteopathic