The anterior common ligament: a broad band of fibres, extending along front of bodies of vertebra, from axis to sacrum. It consists of two sets of fibres, superficial and deep the former extending between the bodies of two, or more vertebra, the latter only between adjacent vertebra. The fibres are attached principally to the intervertebral sub stances. The posterior common ligament is within the spinal canal, and extends along back of bodies of the vertebrae from axis to sacrum, being broad opposite the intervertebral discs, and narrow opposite the bodies, except in the neck, where it is as wide as the bodies. It is attached to the discs and contiguous parts of the bodies of the vertebra. The intervertebral substances, found between the vertebrae from axis to sacrum. The circumference of each consists of layers of oblique parallel fibres of white fibrous tissue, en closing a central part of pulpy elastic material. They are thickest in the lumbar region, and they give the peculiar curves to the column by their differences in thickness.