Fig. 5.

Structures of the intervertebral region. (A) Longitudinal methacrylate section stained with toluidine blue. The intervertebral ligament is composed of an inner notochordal sheath (ns), the external elastic membrane of the notochord (arrow), and the external collagenous ligament (arrowhead), which is an integrated part of layer 2. All these structures are acellular. (B) Longitudinal paraffin section stained for elastin (black) with Verhoeff's haematoxylin. The elastic membrane in the intervertebral region (arrow) thickens continuously during growth, and has a tapered longitudinal profile towards the vertebral region, where it is continuous with the external elastic membrane of the notochord. Scale bar, 50 µm.