[Anatomy and physiology of the nasolabial muscles in a normal subject and in one operated for maxillolabial cleft. Allowance in the treatment of their sequelae for the orthodontic era].

Surgery of the clefts of lips and jaws, particularly the prevention or correction of their sequels, is based on a sound knowledge of the anatomy and physiology of the mimic muscles. Their function is essential for the morphogenesis of the underlying skeletal structures. To restore the physiological functional pattern of all of these muscles is the aim of any surgical procedure in these cases. If the sequels of the cleft are of a certain importance at the time when orthodontic treatment usually takes place, it is indispensable to restore a well-balanced muscle function. Surgery might be done before or immediately after orthodontic treatment, but anyway it has to be done at this age, when the child is still going through a period of intensive growth. The last corrective measures only, aimed at merely aesthetic improvements (surgery upon nasal cartilage and revision of scars), are deferred until growth has ceased.