Degenerative Myelopathy (DM), previously known as chronic degenerative radiculomyelopathy, is a progressive neurological condition causing gradual loss of hindlimb motor function. It is more common in large breed dogs, such as the German Shepherd Dog.

Initially, the onset of the condition is mild, and dogs may show signs of subtle (and non-painful) weakness asymmetrically in the pelvic limbs. As nerve function becomes impaired, signs may progress to ataxia (a lack of coordination), more severe and symmetrical hindlimb weakness and muscle wastage, as well as a reduction in proprioception. Unfortunately, as there is no cure for this condition, it slowly progresses up the spinal cord to affect the forelimbs and eventually leads to paralysis.

This degenerative spinal cord disease is often associated with a genetic abnormality; however, the exact cause is currently poorly understood. As many of the clinical signs are similar to those seen in other spinal conditions, diagnosis involves a process of elimination. This often involves blood tests as well as MRI imaging to rule out other spinal injuries such as spinal fractures and IVDD.