## Overview Fracture of the axis (second cervical vertebra), particularly of the dens (odontoid process), is a serious traumatic injury. In foals the fracture often occurs through the dens growth plate; in adults mid-body or cranial fractures result from hyperflexion. Displacement can compress the spinal cord, producing ataxia, paresis, or sudden death. The physis of the dens closes between 8 and 12 months of age. ## Causes Falls over backward, collisions, and hyperflexion injuries (for example, during jumping or racing) are the usual causes. The ligamentous attachments of the dens transmit force that can avulse or fracture the process. ## Diagnosis Acute neurologic signs or neck pain after trauma raise suspicion. Radiographs may show dens displacement or a mid-body fracture line. Computed tomography provides definitive characterization and assesses spinal-canal compromise. ## Treatment Minimally displaced fractures in foals have been successfully repaired with surgical reduction and stabilization. Adult mid-body fractures may be managed with locking-plate fixation in selected cases. Conservative management is appropriate only for stable, non-displaced fractures without neurologic deficits. ## Recovery and Prognosis Prognosis is guarded and depends on the degree of cord compression and the success of stabilization. Foals treated promptly for dens physeal fractures can recover good function. Severe displacement or delayed treatment worsens the outlook. ## Prevention Avoidance of situations leading to falls over backward or extreme neck hyperflexion.
acute ataxia or paresis after trauma; neck pain; abnormal head carriage; recumbency in severe cases; sudden death possible
## Overview Fracture of the axis (second cervical vertebra), particularly of the dens (odontoid process), is a serious traumatic injury. In foals the fracture often occurs through the dens growth plate; in adults mid-body or cranial fractures result from hyperflexion. Displacement can compress the spinal cord, producing ataxia, paresis, or sudden death. The physis of the dens closes between 8 and 12 months of age. ## Causes Falls over backward, collisions, and hyperflexion injuries (for example, during jumping or racing) are the usual causes. The ligamentous attachments of the dens transmit force that can avulse or fracture the process. ## Diagnosis Acute neurologic signs or neck pain after trauma raise suspicion. Radiographs may show dens displacement or a mid-body fracture line. Computed tomography provides definitive characterization and assesses spinal-canal compromise. ## Treatment Minimally displaced fractures in foals have been successfully repaired with surgical reduction and stabilization. Adult mid-body fractures may be managed with locking-plate fixation in selected cases. Conservative management is appropriate only for stable, non-displaced fractures without neurologic deficits. ## Recovery and Prognosis Prognosis is guarded and depends on the degree of cord compression and the success of stabilization. Foals treated promptly for dens physeal fractures can recover good function. Severe displacement or delayed treatment worsens the outlook. ## Prevention Avoidance of situations leading to falls over backward or extreme neck hyperflexion.
acute ataxia or paresis after trauma; neck pain; abnormal head carriage; recumbency in severe cases; sudden death possible