Abstract
Aim of study: To either confirm or challenge the cervical disc model proposed by Mercer and Bogduk regarding the discontinuation of the anulus fibrosus fibers surrounding the nucleus pulposus. In their model the anulus fibrosus consists of a crescentic mass of collagen which is thick anteriorly, tapering laterally toward the uncinate processes and reduced posteriorly to a thin layer of paramedian, vertically orientated fibers.
Methods: Whole cervical spinal columns were dissected out from six human adult embalmed cadavers. The soft tissues, spinous processes and posterior arches were removed. The specimens were decalcified and transverse sections were cut from levels C2-C3 to C7-T1. Each level was cut into at least three transverse sections: above and below the respective endplates and through the middle of the disc. Sections with an intact IVD and clear anulus fibrosus were studied through a dissection microscope. A total of 27 discs were included.
Results: In most of the sections the anterior aspect of the annulus fibrosus was thicker than the posterior aspect. The posterolateral fibers were absent in only 11 out of 27 discs. In 10 discs we found
the outer fibers of the anulus fibrosus to taper laterally toward the uncinate processes, whereas the inner fibers of the anulus fibrosus curved posteriorly to complete the anular ring. In the remaining 6
discs degenerative signs prevented visualisation of the complete ring, though the posterolateral anulus fibers were clearly visible. The presence of posterolateral anulus fibers depended on the height of the section in relation to the position of the uncinate processes. The continuous lamellae were observed in the sections below the tip of the uncinate processes.
Conclusions: We confirm that the anulus fibrosus is generally thicker anteriorly than posteriorly and that the outer lamellae attach to the anterior rim of the uncinate processes. However, we do not
agree that the anulus fibrosus is always completely interrupted posterolaterally: in sections below the tip of the uncinate processes, the inner layer of the anulus fibrosus may completely surround the nuclear core.
Methods: Whole cervical spinal columns were dissected out from six human adult embalmed cadavers. The soft tissues, spinous processes and posterior arches were removed. The specimens were decalcified and transverse sections were cut from levels C2-C3 to C7-T1. Each level was cut into at least three transverse sections: above and below the respective endplates and through the middle of the disc. Sections with an intact IVD and clear anulus fibrosus were studied through a dissection microscope. A total of 27 discs were included.
Results: In most of the sections the anterior aspect of the annulus fibrosus was thicker than the posterior aspect. The posterolateral fibers were absent in only 11 out of 27 discs. In 10 discs we found
the outer fibers of the anulus fibrosus to taper laterally toward the uncinate processes, whereas the inner fibers of the anulus fibrosus curved posteriorly to complete the anular ring. In the remaining 6
discs degenerative signs prevented visualisation of the complete ring, though the posterolateral anulus fibers were clearly visible. The presence of posterolateral anulus fibers depended on the height of the section in relation to the position of the uncinate processes. The continuous lamellae were observed in the sections below the tip of the uncinate processes.
Conclusions: We confirm that the anulus fibrosus is generally thicker anteriorly than posteriorly and that the outer lamellae attach to the anterior rim of the uncinate processes. However, we do not
agree that the anulus fibrosus is always completely interrupted posterolaterally: in sections below the tip of the uncinate processes, the inner layer of the anulus fibrosus may completely surround the nuclear core.
| Original language | English |
|---|---|
| Pages (from-to) | 52-52 |
| Number of pages | 1 |
| Journal | Osteoarthritis and Cartilage |
| Volume | 12 |
| Issue number | sB |
| Publication status | Published - 2004 |
| Event | 9th World Congress of the Osteoarthtritis Research Society International (OARSI) - Chicago (USA), Chicago, United States Duration: 2 Dec 2004 → 5 Dec 2004 |