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Myelogram, X-ray



A myelogram is a diagnostic tool used to determine spinal cord compression. It is a radiographic study in which a special dye is injected into the space within the spinal canal surrounding the spinal cord. Regular spinal radiographs only provide a clear picture of the bones.

The dye is radiopaque (impenetrable by X-ray) and it allows the examiner to better visualize the spinal cord, exiting nerves and nerve canal. Radiographs (X-rays) are then taken in special positions and analyzed. In horses, spinal cord compression is usually found in the neck.

The horse is anesthetized and an area behind the ears is clipped and surgically prepared. A long needle is introduced carefully into the space around the spinal cord. Fluid bathing the spinal cord (cerebrospinal fluid) is usually harvested for lab analysis at this time and the dye is injected. A series of radiographic images are taken with the neck in various positions. These are interpreted by studying the dye columns above and below the spinal cord.


Myelogram provides greater visualization of the spinal cord by defining and highlighting the area around it. It is much more sensitive than plain neck radiographs, and much more helpful in determining whether a horse has a spinal cord compression.


Often, only the spinal cord from the head to the withers (the cervical or neck region of the spine) may be visualized due to the limitations of the x-ray generator used. Large private practices and university teaching hospitals may have more powerful x-ray generators that allow for visualization of more of the spinal cord.

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Author: Doug Thal DVM Dipl. ABVP


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