Patients with scoliosis meet me and ask: Why do I have scoliosis? This is a question that is both simple and complex, starting with each type of crural scoliosis. Idiopathic Crestal Scoliosis “Idiopathic” means that the cause is unknown. We don’t know exactly what causes this most common type of scoliosis (80-85%), and it is thought to be related to genetic, hormonal, endocrine, growth and developmental abnormalities, as well as dysfunction of the neurological balance system. The term “congenital” does not refer to an entirely genetic condition, but rather to an abnormality in the shape and structure of the vertebrae that occurs during fetal development: one or more of the vertebral structures of the crural vertebrae are not fully formed or the crural vertebrae are not segmented properly. This type of scoliosis may be accompanied by other conditions, such as malformations of the heart or kidneys. Congenital crural scoliosis is associated with genetic factors, as well as a variety of environmental factors such as lack of oxygen or vitamin deficiencies during embryonic development at the time of pregnancy. Neurofibromatosis crural scoliosis This is caused by the destructive erosion of the crural vertebrae by a neurofibroma, the underlying cause of which is a neurofibroma. Neuromuscular Crestal Scoliosis Any condition that involves nerves and muscles can lead to crestal scoliosis, most commonly due to muscle imbalances and weakened muscles. Neuromuscular disorders that commonly lead to scoliosis include cerebral palsy, myasthenia gravis, and crural injury. Degenerative Crestal Scoliosis This type of crestal scoliosis often occurs in older adults, especially older women, due to degenerative disc aging and osteoporosis of the crest. It is important to note that postural scoliosis is not true scoliosis! The biggest difference between the two is that postural scoliosis can be corrected by the body itself, while true scoliosis cannot be corrected by the body itself.