It is called scoliosis. It is a curvature to the side, convex to one side and concave to the other. This is accompanied by rotation of the spine and, because the ribs are attached to the rotated spine, the chest wall becomes more prominent on one side. Scoliosis, if severe, can be uncomfortable or painful and limits the function of the lungs and the upper limbs. It is also disfiguring.
Scoliosis worsens most rapidly when growth is most rapid, in the latter stages of puberty.
If scoliosis is not severe by the time the peak rate of growth in height has been passed, it is unlikely to become severe. Increasingly, scoliosis in people with DMD is treated surgically. The timing of surgical treatment is critical because the ability of a person with DMD to undergo such major surgery with safety is constantly diminishing with age because of diminishing lung function. A decision about surgery is often taken before the scoliosis has become severe, in anticipation that it will do so if untreated. Any suspicion that scoliosis is developing should be reported to the attending doctor or therapist.