Pathophysiology of musculoskeletal disorders

¶ … alterations which can occur in the musculoskeletal structures of the foot and lower legs. Essentially, metatarsus adductus is a foot deformity that is caused by the development impaired by an infant's position in its mother's womb. The delicate bones in the foot are bent inwards towards the infant's body (Carroll, 2008). There are a number of positional issues that can cause the condition, but include a breech position for extended periods of time. Moreover, a hereditary condition known as ogliohydramnios, where the mother fails to produce a sufficient amount of amniotic fluid causes the deformity. This can cause the infant to suffer from developmental dysplasia of the hip (DDH) as well. Equinovarus deformity is a type of club foot, where the foot is also bent inwards towards the body. There are three types of equinovarus deformities, positional equinovarus, idiopathic congenital equinovarus, and teratologic equinovarus. These feature a combination of equinus deformity which is a "plantar flexion of the foot in which the heel is lower than the toes" and valgus deformity, the "eversion and abduction of the heel and forefoot" (Carroll, 2008, p 1622). These are often caused by genetic disorders. The idiopathic equinovarus deformation in newborns often occurs more in males and is a type of clubfoot which can be treated with both surgery and use of braces. Teratologic equinovarus has neuromuscular or syndromic causes such as arthrogryposis and osteochondrodusplasia. Finally, pes planus is a type of flat foot, rather than club foot like the others discussed. This is often a condition passed down within the family and is essentially when the arch of the foot collapses. Most flay feet cases in children will eventually develop healthy arches with the development of healthy muscle, tendon, and bones. However, pes planus can also occur in adulthood, with the increased production of proteolytic enzymes which can cause and increased breakdown of tendon tissue, causing the arch to collapse (Crowther- Radulewicz & McCance, 2008).

Muscular dystrophy and myasthenia gravis are complicated conditions. According to the research, muscular dystrophy is a "group of familial disorders that cause degeneration of skeletal muscle fibers" (Carroll, 2008, p 1633). Many researchers believe that the different types are each caused by different biochemical defects. For example, Duchenne Muscular Dystrophy is thought t be the result of a single gene defect "thought to be caused by a deletion of a segment of deoxyribonucleic acid" (Carroll, 2008, p 1633). Similarly, Becker Muscular Dystrophy is also caused by deformities in the X-link. Different types of dystrophy affect different muscle groups. There is the example of scapuloperneal Muscular Dystrophy, which affects the facial and shoulder muscles. Myasthenia gravis is an autoimmune neuromuscular condition, caused by abnormal transmission of nerve impulses to the affected muscle groups. Normal communication is interrupted, where antibodies disrupt the flow of acetylcholine between nerves and muscles. It is also a condition which weakens the skeletal muscles, especially after activity. Smaller muscles, such as those involved with controlling facial expression, eye and mouth movement are often affected by the disease.