My Chiropractor showed me via X-ray that I have a straight cervical spine (Should be curved for normal nervous system and immune function), he said that this is a one way street and it is hard to restore the curve, we just need to stop further degeneration
Also my shoulders have rounded inwards, I try to force them back as much as I can to relieve tension on upper back muscles and chest but the general muscle weakness causes this not too hold. All of my joints have been significantly weakened - particularly my knees which constantly 'crack' loudly and have visibly fallen inwards, changing the way that all of my leg muscles are working and causing some discoordination.
As someone who used to be fairly sporty, this is all very hard to accept as I would love to one day return to sports after recovery but don't know if I will be able to, the spinal stuff is of course the most concerning....
It makes it even more frustrating when it is said to be a psychosomatic disorder, we need a catalogue of Skeletal X-rays of PWME to reveal the truth....
The important thing is to distinguish the position you hold the skeleton in from actual changes in joint mobility.
The cervical spine is normally straight if x-rayed in flexion and curved if x-rayed in extension. (You think it would be straight when you are straight up but actually it is the reverse.) Unless the x-ray was done in a chosen posture whether it is straight or curved means nothing. To tell if there is a problem with the range of movement of the spine and shoulders all you need to do is stand against a wall. If the spine and shoulders are mobile you should be able to stand with heels, buttocks, shoulder blades and back of head all against the wall. If it is hard work to get the head against the wall there is likely to be some loss of flexibility.
Shoulders can droop either down or forward. Downward drooping as in Charlie Chaplin drooping shoulders, as opposed to Muhammed Ali's square shoulders, is due to absence of much meat (muscle) between the shoulder girdle (collar bone and shoulder blade) and the ribcage. I think the relevant muscles may be serratus anterior and subscapularis. So basically it is a matter of how much heavy work you do with your arms. Having sloping shoulders is fine if you are not wanting to be an athlete and indicates no medical issue. You can raise your shoulders using the trapezius muscle but you have to do this on purpose so when at rest or in a relaxed walk you do not control your shoulder shape - the meat mass does. (Or your raincoat shoulder pads.)
Shoulders will droop forward if the thoracic spine in held in a forward curve and that is what increases as people get older. A lot of people stand with their head jutting a bit forward with a slight shoulder hump by fifty, but others remain straight as a ramrod. By seventy the head jutters are obviously bent but the ramrods are often still straight.
What is happening here is that the discs in the thoracic spine are developing a fixed wedge shape with the front thinner than the back. The bones of the spine do not change shape at all unless they fracture so most old people have bent spines because of their discs, not bones. Nobody knows exactly what happens as there are no controlled trials of standing up straight for forty years. However, it seems clear that some people lose the ability to keep their discs flat and gradually bend forward with the front of the disc becoming fixed as narrow so that however hard they try they cannot stand straight. But there are various bits of evidence from conditions with abnormal muscle function indicating that the way people hold themselves does matter. It is likely that if you hold your thoracic spine bend forward in middle life the discs gradually solidify in a wedge shape and then you cannot straighten. So the sensible thing to do seems to be to make sure you deliberately keep the spine straight at least some of the time.
What may be most important is lying in bed. I suspect that it is a good idea to ensure that some of the night you lie on your stomach with the spine straightened out. This is a standard recommendation for ankylosing spondylitis, where the wedging of discs becomes fixed by bony bridges. I also suspect that no more than one thin pillow is a good policy.
It is true that some elderly people have a curved spine because of wedged vertebrae from fractures but there was an interesting Dutch study that suggested that the people who wedge their vertebra forward are those who are already bending forward because of wedged discs.
A small proportion of people get trouble with the cervical spine as well, with disc wedging. This can be associated with degenerative change at the margins of the vertebrae and sometime there is a specific forward being at one level. I suspect the same basic principle applies that keeping an upright posture is the best defence against curvature. Manipulation is not good idea and can cause serious harm in the neck region.
I don't think there is any particular reason to think that any of this has any relation to ME, except that PWME may adopt poor postures in chairs or beds I suppose.
Cracking joints are generally not a sign of disease. They usually indicate a vacuum occurring in the joint. That may be more likely to happen in joints that are not routinely used in regular exercise since movement of joints stimulates the production of the lubricating fluid. If a joint surface is damaged, as in a knee for instance, then clunking noises can develop, but most people do not refer to that as cracking. I suspect cracking joints in ME is not a sign of any disease but simply lower levels of use.