What is the primary mechanism of injury for an anterior compression fracture of C3-C7?

The primary mechanism of injury for an anterior compression fracture of the cervical spine, particularly at the C3-C7 levels, is hyperflexion. When the head is moved forward relative to the chest, excessive flexion can result in the loading of the anterior vertebral bodies. This force can lead to a wedge-shaped fracture, where the anterior portion of the vertebra collapses due to the compressive forces.

In cases of hyperflexion, the neck is bent sharply, creating a significant load that specifically affects the front part of the vertebrae. This is distinct from other mechanisms such as hyperextension, which tends to produce different types of injuries, often involving ligament sprains or tearing, and potentially leading to posterior compression fractures or other soft tissue damage. Rotation and distraction mechanisms also involve different physiological impacts on the cervical vertebrae and are less commonly associated with anterior compression fractures compared to hyperflexion.

Thus, understanding the mechanics of hyperflexion provides crucial insight into how such injuries typically occur in the cervical spine and underscores the importance of recognizing these patterns in clinical assessments.