[Radiologic description of the growth plates of the atlas and axis in foals].

This research investigates the growth plates of the first two cervical vertebrae, atlas and axis, in foals, their times of closure and their visibility on X-ray and computed tomography (CT) scans. The findings contribute to the diagnosis and treatment of possible fractures in these areas caused by falls or impact.

Understanding Atlas and Axis Growth Plates

• The atlas vertebra in a foal has three primary growth plates: two ventrolateral plates and one dorsomedian cartilaginous plate. These plates are crucial to growth and development but also pose potential fracture points during the foal’s early life.
• The dorsal plate is visible on a dorsoventral X-ray projection until the foal is around 12 months old. The ventrolateral growth plates, however, are not visible on either dorsoventral or laterolateral X-rays, as they close when the foal is about six months old.
• Compared to X-ray imaging, CT scans provide a clearer and more detailed visualization of the atlas’s ossification centres. This is particularly useful as the foal matures and the growth plates close, reducing their visibility on radiographs.

Insights into the Axis Vertebra

• In the axis vertebra, the cartilaginous gaps (growth plates) between the dens axis and the cranial epiphysis can be seen in normal X-ray radiographs, in both planes of the projection.
• Other growth plates are also present, such as those between the corpus vertebrae and the arcus vertebrae of the axis. These are not visible on regular X-ray projections but become clear on transversal CT scans.
• The growth plates between the corpus vertebrae and the arcus vertebrae of the axis ossify when the foal is three to four months old, thus disappearing from imaging scans.
• The growth plates between the dens axis and the cranial epiphysis close around the end of the first year. The cranial and caudal epiphyseal plates are gone by around four to five years of age.

Implications for Veterinary Practice

• The research helps in accurately diagnosing and treating fractures in the cervical area of foals. Differentiating between fractures and growth plate areas within vertebrae will be of great importance when assessing injury severity and appropriate treatment methods.
• The more precise ability to detect and monitor growth plate evolution in young horses, facilitated by CT scans, can substantially enhance their medical care and management.