Wobblers is generally considered a congenital or traumatic disease that is caused by impingement of the spinal cord by the cervical (neck) vertebrae and is therefore dubbed, cervical stenotic myelopathy (CSM). The symptoms include stumbling, incoordination, and weakness in horses less than three years of age and may be the most common neurological disease in growing horses. As horses have begun to age a second group of wobblers is emerging, the older horse with osteoarthritis of the vertebrae. The arthritis results in instability and narrowing of the spinal canal and impingement on the spinal cord. This article concerns itself with clinical signs, diagnosis, and treatment of CSM.

Horses with CSM are usually weak and/or incoordinated in both the rear legs. Some signs of this are:

• tripping, the toe may catch the ground and knuckly under or the legs may interfere with each other.
• a swaying body or staggering
• variable length or misplaced steps
• an incoordinated or bunny hopping appearance at the canter
• exaggeration of leg action
• worn toes from excessive dragging of the feet

Compression of the cord in the neck first effects the rear limbs and as the compression worsens it can effect both. The reason the rear are effected first is the nerves are more superficial in the cord. Occasionally caudal cervical narrowing (C6 or C7) may result in the forelimbs being worse. Though both sides of the horse are affected, one side may be worse than the other. This is an important finding because it separates this disease from another important cause of incoordination, equine protozoal myeloencephalitis, which causes weakness and incoordination usually just on one side.

The signs may worsen when the horse is circled, the head elevated, or the horse attempts to negotiate a hill. Many horses also have signs of stiffness in the neck do to painful nerve root impingement. Degeneration of muscles of the neck can occur though not common.