A neck movement that may feel routine can become a much riskier event when bone has narrowed the space around the spinal cord. This study found that twisting the neck under those conditions can sharply raise mechanical stress. There are few studies focusing on how spinal cord injury may be mechanically related to bone growth during neck rotation.

This study examined the effects of neck rotation on the spinal cord, its protective covering, and the nerve roots when that bone growth is present. The central question was simple: when the space around the spinal cord is already narrowed, what happens to these tissues during a forceful neck movement?

The specific mechanical effects of neck rotation on the spinal cord and nearby tissues in this condition had not been studied before. Bone growth along the spinal canal is also a major contributor to disease affecting the spinal cord. So the study compared mild, moderate, and severe narrowing, using a computer model to examine how the tissues were loaded.

The model represented the neck, the spinal cord, and the tissues inside the spinal canal. It simulated the bone pressing on the spinal cord while the body was still and while the neck was moved. A useful everyday picture is a cable inside a narrow sleeve: if the sleeve is already pressed inward, twisting the cable leaves less room for it to move safely.

Three models were made by adding mild, moderate, and severe bone growth to an otherwise healthy neck model. The categories were based on how much of the spinal canal the growth occupied. The modeled growth was placed at the C five and C six neck levels, where free space around the spinal cord was relatively narrow after neck rotation while bent forward.

During neck rotation, spinal-cord stress increased as the bone growth became more severe. Compared with the model without bone growth, stress increased by nearly forty percent in the severe model. In the severe model, the highest stress first appeared at the level where the bone was pressing on the spinal cord, before shifting higher in the neck later in the movement.

As the abnormal bone growth becomes more severe, stress spreads through the spinal cord’s covering and concentrates around the nearby nerve roots. That matters because movement may strain not only the cord itself, but also the structures carrying signals to the limbs.

The study also examined the protective covering around the spinal cord when the bone touched that covering without touching the cord itself. This helped assess whether the surrounding tissue could still experience mechanical loading. The maximum stress in that covering was much lower when the compression was held still than when it occurred during movement.

The movement, rather than pressure alone, made the difference larger. The results suggested that some degrees of canal narrowing caused by bone growth could significantly increase stress on the spinal cord and the tissues around it. Clinically, the study indicates high risk for neck rotation while bent forward in patients with this condition.

For someone living with spinal-canal narrowing, the study supports caution before forceful manipulation, especially neck rotation while bent forward, and careful attention to the available space around the spinal cord. The study suggests that neck rotation while bent forward may be high risk when bone growth has narrowed the spinal canal.

For patients with this condition, that finding supports caution and careful clinical judgment before manipulation.