How Slouched Posture Causes Neck, Shoulder and Upper Back Pain because of Forward Head and Destabilized Shoulder Blades. The Benefits of Improved Posture.

 

— Forward Head
— Benefits of Improved Posture–#1
— Destabilized Shoulder Blades 
— Benefits of Improved Posture–#2
— How Destabilized Shoulder Blades Cause Neck and Upper Back Pain
— Methods for re–orienting/re-stabilizing the shoulder blades
— Fix the Neck Exercise Reduces Excessive kyphotic curve of the upper back and
    Strengthens Upper Back Extensors
— Sustained correction of slouched posture in Standing and Sitting

1. Forward Head: When posture is slouched, the chest "caves in," the shoulders round forward, the upper back hunches over (increased kyphotic curve) and the shoulder blades (scapulas) rotate/tilt down to the front. The increased kyphotic curve causes the neck to crane out, causing the bowling-ball-sized head to be held forward of the center of gravity. For each inch forward, the force needed to support the head's weight increases by ten pounds per inch. At 3 inches forward, the average 10 pound head feels like 30 pounds (Cailliet). It's the back neck extensors that must bear the increased weight by contracting more forcefully to keep the out–of–balance head from falling further forward, while the front neck flexors, especially the deep neck flexors, which are supposed to help in balancing the head by pulling it forward aren't needed much at all. Over time, habitual Forward Head causes the back neck extensors to weaken and atrophy from chronic tightness and spasm, which squeezes out oxygen and nutrient–rich blood, thus starving the muscle. At the same time neck flexors weaken and atrophy because they are hardly used at all (disuse atrophy). (Jull)  And of course all this spasm and tightness causes pain, especially at the back of the neck.  

 Benefits of Improved Posture–#1 requires realignment of the entire body. But simply taking a deep breath and expanding the chest goes a long way to reducing thoracic kephosis, straightening the mid-back, and helping one to feel what improved posture is like. However, maintaining improved posture is difficult because important muscles that support improved posture have become too weak, and muscles that work against improved posture have become too strong and short. For exercises that helped me, see Fix the Posture.  Once posture is improved and the head is held more in line with its base of support, the back neck muscles (Neck Extensors) and front neck muscles (Neck Flexors) are able to work together to keep the head steady, balanced and eyes level with the least amount of effort.   A byproduct of improving Forward Head is the re-balancing and strengthening of neck muscles.Flexors that weakened and atrophied from disuse (My neck flexors were so weak I couldn't lift my head from the pillow.) now do more of the work of keeping the head upright; extensors that were spasmed and atrophied from overwork are less stressed.Direct neck exercises are not needed to regain neck strength. (Surprising to me, I recovered the ability to lift my head from the pillow without additional neck exercises.) However, when spasm and inflammation have subsided, neck exercises can be done for extra strengthening. See Professor Jull's Whiplash Injury Recovery: A Self-Management Guide—a free download! Also the following YouTube video: Deep Neck Flexor Training. (Jull's key instruction for the neck flexor exercise is that a patient lying on the back, can feel the back of his/her head slide up the bed as they nod or tuck their chin, which stops substitution movement of more superficial neck muscles in place of the deep neck flexors, which are the important muscles in need of strengthening.)      

2. Destabilized Shoulder Blades: InSlouched Posture the thoracic spine (upper and mid back) is hunched/kephotic. The shoulder blades are held wider apart because the muscles between them (Rhomboids, and Middle and Lower Trapezius) must stretch for the kephotic spinal curve to bulge out. At the same time the chest "caves in" as Pectorals (Pectoralis Major and Minor) and Intercostals (muscles between the ribs) contract and shorten to "take up the slack," which rounds the shoulders and arms in toward the chest. If slouched posture is habitual, the Rhomboids, and Upper and Lower Trapezius muscles, which also anchor the shoulder blades to the spinal column of the back, stay elongated and weaken (stretch weakness and atrophy).The shoulder blades no longer serve as a stable platform for arm use. (Top outer corner of the shoulder blade forms the "socket" for the "ball" of the upper arm bone—the humerus. See shoulder or glenohumeral joint.) Shoulder blade stabilizing muscles also control shoulder blade movement, and are needed for the shallow shoulder joint to accommodate a wide range of arm movements without dislocating. (See illustration below)    Other indicators of weakness in shoulder blade stabilizer muscles include feeble gliding movements of the shoulder blades when the arms are being raised (as observed from back) and poking up of shoulder blades edges or "winging," rather than hugging the back ribs. See "Function of the Shoulder Blades" for more information.

Benefits of Improved Posture–#2, the back neck extensors are more relaxed. The shoulder blades are held closer to the spine. The shoulders come back to a more normal position, which allows the chest to expand, and stretches the pectoral muscles underlying the breast area and the intercostal muscles between the ribs, so that they return to a normal length.

The muscles that anchor the shoulder blades to the spine, the rhomboids, and middle and lower trapezius are normal length and strength.

How Destabilized Shoulder Blades cause Neck and Upper Back Pain: Because the Rhomboids, and Middle and Lower Trapezius muscles are stretched and weak, the work of anchoring the shoulder blades to the spinal column passes to the Levator Scapula and Upper Trapezius, both of which can't avoid their anatomical role of suspending the shoulder blades from the neck/cervical spine. But these two muscles aren't adequate for the extra load* and in response they become hyperactive and remain tight, always trying to pull the shoulders up toward the ears. Use of the arms in weight bearing activity such as in lifting or pulling adds to the load, and may cause the upper traps and levator scapula to spasm. Focal points of hyperactivity are felt as tender knots at the levator scapulas' points of attachment to the shoulder blade (red X in illustration above and at left). Unfortunately in slouched posture, the levator scapula and the upper trapezius are also stretched—their points of attachment on the shoulder blade having moved further away. Being simultaneously stretched and "shouldering" more of the work of stabilizing the shoulder blades, the upper traps and levator are in a bind—not able to strengthen adequately because they're stretched and yet also overworked. Even small muscle strains have difficulty healing and occur more often, becoming chronic. And chronic muscle damage becomes chronic inflammation and chronic pain. Inflammation at origin points of the levator scapula and upper trapezius on the cervical spine and back of the head cause side and back neck soreness/pain, and headaches (Cervicogenic/occipital headaches). Chronic soreness/pain of the upper back and fleshy triangle between the neck and shoulder (body of the upper trapezius) is common. (Cailliet).
Pain due to inflammation of the levator and upper trap. may flare with neck massage or neck exercise. 

*the weight of the arms hangs off the upper outside edge of the shoulder blades (shoulder joint). Half of that weight is transmitted to the spinal column in back via the Rhomboids and Trapezius. If Rhomboids and Trapezius are weak the weight is borne by Levator Scapula and Upper Trapezius (Darn Uncomfortable!). The rest of arm weight is transmitted via the anterior (front) shoulder girdle joints and rib cage to the spinal column (acromion process of shoulder blade—›collar bone—›sternum—›costal cartilages—›ribs—›thoracic vertebra). 

Methods for re–orienting/re-stabilizing the shoulder blades: for those with neck spasm, pain and inflammation that worsens with arm use, re-stabilizing the shoulder blades is difficult. The usual therapeutic exercises for shoulders, such as seated rows and pull downs that use the arms in pulling or lifting weights, can be painful unless there's already some degree of shoulder blade stabilization. Otherwise, spasm and pain prevents the effort from going into strengthening the rhomboids, and middle and lower traps, instead of the over-worked default muscles—the upper traps and levator scapula. I wasn't able to activate the correct muscles during my 4 plus courses of Physical Therapy for neck and shoulders. I knew the effort was supposed to be coming from the shoulder blades area and not the arms, but that was next to impossible when one's back and shoulder blades are like an unknown territory. Without a good way to see what should be activated, there is lack of innate body feel for what is really going on back there. It was much later that I discovered that it was possible to learn to contract and strengthen the muscles that control shoulder blade movements without using the arms, but mirrors were needed for visual feedback. And thus the "Fix the Shoulder Blades" exercise is done with a swivel mirror and another larger mirror to provide visual feedback. (Turns out that many of these muscles are only innervated with motor nerves, not sensory nerves, so controlling the shoulder blades would be tough for a lot of people.)   Eventually when the problem of neck spasm with arm use is minimized, the usual therapeutic exercises are better tolerated and useful for further strengthening.     see... Fix The Shoulder Blades Exercise. Also see the following video:Front/Lateral Raises, which shows the effect of poor scapular control on tension in the upper shoulder/back area and neck during front and lateral raises with light weights.

"Fix the Shoulder Blades" reduces the excessive kyphotic curve of the upper back (but only if it is still flexible) and strengthens the upper back extensors, probably through activation of the middle and lower parts of the trapezius, which "reinforce the upper back extensors and help to hold the shoulders back." (Kendall)

Sustained correction of slouched posture also depends on reminding oneself to straighten the mid-back and lift the chest throughout the day. This also applies to sitting, where slouching seems almost automatic. Sit straight on the butt, not on the lower back, and maintain the lumbar curve by sitting back in a chair with a lumbar support. Keep the chest high. For a neat reminder see the "4-Finger Posture Correction in Sitting" Video. And learning to stand straight can also be a challenge. I finally understood that I had always been leaning forward when I found it felt unnatural to stand straight against a wall—with butt, shoulders/upper back, head** touching and knees slightly bent. (**if the back of the head doesn't touch, do not force and do not tilt it back; but straighten excessive thoracic kephosis, if still flexible, with a deep breath, which will bring the head back, or do Fixing the Shoulder Blades Exercise) The longer good posture is maintained, the more natural it feels and the stronger the postural stabilizing muscles. Maintaining good posture is difficult; but doing it strengthens postural stabilizing muscles (the Core) and in itself is legitimate exercise. See Fix the Posture.