Muscle contracture refers to physical shortening of muscle length, and it is often accompanied by physical shortening of other soft tissues such as fascia, nerves, blood vessels, and skin. Possible reasons for muscle contracture and fibrosis include external and exercise-induced trauma, neuropathy or myopathy, and muscle ischemia and necrosis. Muscle contracture and fibrosis does not seem to be painful by itself, but irreversible loss of muscle function occurs. This can also impair function of adjacent joints, can lead to secondary joint pathology, and may result in a completely non-functional limb, depending on which muscle is affected.
Muscular dystrophy is a group of inherited diseases that damage and weaken your muscles over time. This damage and weakness is due to the lack of a protein called dystrophin, which is necessary for normal muscle function. The absence of this protein can cause problems with walking, swallowing, and muscle coordination. There are more than 30 different kinds of muscular dystrophy, which vary in symptoms and severity. Muscular dystrophy can occur at any age, but most diagnoses occur in childhood. Young boys are more likely to have this disease than girls.
Spinal muscular atrophy is a genetic disorder that affects the control of muscle movement. It is caused by a loss of specialized nerve cells, called motor neurons, in the spinal cord and the part of the brain that is connected to the spinal cord. The loss of motor neurons leads to weakness and wasting (atrophy) of muscles used for activities such as crawling, walking, sitting up, and controlling head movement. In severe cases of spinal muscular atrophy, the muscles used for breathing and swallowing are affected. There are many types of spinal muscular atrophy distinguished by the pattern of features, severity of muscle weakness, and age when the muscle problems begin.