Banded structures in human nucleus pulposus.

We studied 20 intervertebral disks from cervical, thoracic, and lumbar levels from patients 12 hours to 55-years-old by electronmicroscopy. Tissue was obtained at operation from 10 patients with scoliosis and 6 with herniation of the intervertebral disk. Four intervertebral disks were removed at autopsies performed within 4 hours of death. Banded structures distinct from native collagen were present in the nuclei pulposi of all intervertebral disks but not in the annuli fibrosi. These structures may be an unusual form of collagen, however they closely resemble extracellular banded structures found in frog muscle spindle that may form from find filaments when the muscle spindle increases in length.