Cerebral palsy
Cerebral palsy is characterized by abnormal muscle tone, reflexes, or motor development and coordination. The neurological lesion is primary and permanent while orthopedic manifestations are secondary and progressive. In cerebral palsy unequal growth between muscle-tendon units and bone eventually leads to bone and joint deformities. At first, deformities are dynamic. Over time, deformities tend to become static, and joint contractures develop. Deformities in general and static deformities in specific (joint contractures) cause increasing gait difficulties in the form of tip-toeing gait, due to tightness of the Achilles tendon, and scissoring gait, due to tightness of the hip adductors. These gait patterns are among the most common gait abnormalities in children with cerebral palsy. However, orthopaedic manifestations of cerebral palsy are diverse. Additionally, crouch gait -excessive knee flexion gait- is prevalent among children who possess the ability to walk. The effects of cerebral palsy fall on a continuum of motor dysfunction, which may range from slight clumsiness at the mild end of the spectrum to impairments so severe that they render coordinated movement virtually impossible at the other end of the spectrum. Although most people with CP have problems with increased muscle tone, some have normal or low muscle tone. High muscle tone can either be due to spasticity or dystonia.