[The "envelope" versus the biomechanical function of the spine].

As a continuation of argumentation presented in a number of previous communications, the author advocates the view according to which the developing spine and its neural content ["spinal cord-nerve roots complex"] are linked by an equally intimate morphogenetic relation like that existing between the brain and its skeletogenic envelope. A specific feature of the neurovertebral developmental relation consists in the fact that the elongated spinal cord-nerve roots complex is enveloped by its skeletogenic case both in the transversal and in the longitudinal direction. The matter is further complicated by lagging of the spinal neural growth behind that of the vertebral column. The development of the basic anatomical features of the individual vertebrae such as their length and width, the girth of the vertebral body as well as the shape of the intervertebral foramina cannot be understood without taking into account the gross developmental dynamics of the two main components of the axial organ, viz., of the spinal cord-nerve roots complex and of the vertebral column.