[Idiopathic scoliosis -why predilection for the lower thoracic spine? Explanation from neurovertebral developmental interrelation.].
Structural, functional and clinical disparity of the nervous system and the skeleton implies entirely separate approach to their growth and development, with just one exception, viz., the growing brain which moulds the saucer-like shape of its neurocranial bony envelope. It is suggested that the cerebrocranial ("macroneurotrophic" at the organ level) developmental interrelation represents just the most striking instance of the universal "osteoneural" growth interrelation existing between the entire developing nervous and bony tissues throughout the body, above all in the axial organ but also in the limbs. It is argued that contrary to the isolated, purely "osteological" approach to the growing skeleton, growth in length of the vertebral column (as well as of the limb bones) cannot proceed normally without adequate co-growth of the corresponding nervous macrostructures, viz., of the spinal cord with the nerve roots and of peripheral nerves. With exaggerated lagging behind of the vulnerable neural growth the growing bony skeleton, normal as such, will have to find place, to "accomodate" on the shorter space available along the too slowly growing, for the given developmental stage too short nervous structures, even at the cost of a deformity. The very biological purpose of the latter is to preserve length integrity ("unloading") of the too short spinal nerve roots and/or of peripheral nerves. Idiopathic scoliosis (together with a number of another skeletal malformations) represents one of most outstanding example of "neuroadaptive" deformities the common denominator of which is "shortening as though from below" since insufficiency of neural growth hinders the bony skeleton from growing straightly in the distal direction. Predilection of idiopathic scoliosis for the lower thoracic spine is due to the greater length and, consequently, to higher growth-energetic demands of the lower thoracic spinal cord segments. Key words: idiopathic scoliosis, neurovertebral developmental interrelation, neuroenveloping function of the spine, spinal cord segments, neural growth reciprocity.
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Radiodiagnostická klinika II, FNsP, Brno-Bohunice.