During spinal extension, what happens to the annulus?

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Multiple Choice

During spinal extension, what happens to the annulus?

During spinal extension, the spine bends backward, which creates a bending moment that loads the disc differently on the two sides. The posterior portion of the annulus fibrosus becomes compressed as the posterior elements move toward each other, while the anterior portion is stretched and put in tension to resist the bending. The lamellae are oriented to handle these opposing forces, so the posterior annulus bears compression and the anterior annulus experiences tension as extension occurs. This pattern is the opposite of flexion, where the posterior annulus is in tension and the anterior in compression. So, the description that matches extension is posterior compression with anterior tension.

During spinal extension, the spine bends backward, which creates a bending moment that loads the disc differently on the two sides. The posterior portion of the annulus fibrosus becomes compressed as the posterior elements move toward each other, while the anterior portion is stretched and put in tension to resist the bending. The lamellae are oriented to handle these opposing forces, so the posterior annulus bears compression and the anterior annulus experiences tension as extension occurs. This pattern is the opposite of flexion, where the posterior annulus is in tension and the anterior in compression. So, the description that matches extension is posterior compression with anterior tension.

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