References in classic literature ?
His cranial cavity is continuous with the first neck-vertebra; and in that vertebra the bottom of the spinal canal will measure ten inches across, being eight in height, and of a triangular figure with the base downwards.
The twins (right) were treated at the city's Diana, Princess of Wales Children's Hospital and underwent a 16-hour operation last December to separate their spinal canals and abnormally joined lower spinal cords.