Medulla spinalis
The equine spinal cord is a cylindrical column of neural tissue extending from the brainstem through the vertebral canal to approximately the first sacral vertebra. It is organized into white matter tracts (ascending sensory and descending motor pathways) surrounding a butterfly-shaped core of gray matter containing neuronal cell bodies. The cervical intumescence (C6-T2) and lumbar intumescence (L4-S2) are enlarged regions providing innervation to the forelimbs and hindlimbs respectively. The cord is protected by three meningeal layers (dura mater, arachnoid, pia mater) and bathed in cerebrospinal fluid.
Spinal cord compression (Wobblers syndrome), trauma, and infectious or inflammatory diseases can cause neurologic deficits. Diagnosis uses clinical examination and advanced imaging. Prognosis depends on the cause and severity.
## Overview Equine degenerative myeloencephalopathy (EDM) is a diffuse neurodegenerative disease of the brainstem and spinal cord associated with vitamin E deficiency in genetically predisposed young
## Overview Equine herpesvirus-1 myeloencephalopathy (EHM) is the neurologic form of equine herpesvirus-1 infection. Neuropathogenic strains cause vasculitis and ischemic damage to the spinal cord. T
## Overview Vertebral fracture or luxation with spinal cord compression most commonly occurs at C1-C2, C3-C4, or the thoracolumbar junction. Signs are acute severe ataxia or paralysis caudal to the l
## Overview Equine motor neuron disease (EMND) is an acquired degeneration of lower motor neurons strongly associated with prolonged vitamin E deficiency (usually from long-term lack of green pasture
Wobbler syndrome, also known as cervical vertebral stenotic myelopathy, is a neurologic condition caused by compression of the spinal cord in the neck. It leads to progressive incoordination (ataxia),
Incoordination, weakness, or abnormal gait should be evaluated promptly. Protect the neck and back from trauma.
## Overview Equine degenerative myeloencephalopathy (EDM) is a diffuse neurodegenerative disease of the brainstem and spinal cord associated with vitamin E deficiency in genetically predisposed young horses. It causes symmetric ataxia and weakness, worse in the hind limbs, with onset usually before two years of age. Neuroaxonal dystrophy is a related milder form. ## Causes Genetic susceptibility plus inadequate vitamin E (often from lack of green pasture). ## Diagnosis Clinical signs in a young horse, low serum vitamin E, and exclusion of other causes of ataxia. Definitive diagnosis is histologic. ## Treatment Vitamin E supplementation may slow progression if started early. There is no cure. ## Recovery and Prognosis Poor for significant improvement. Many horses are euthanized due to progressive ataxia. ## Prevention Adequate vitamin E, especially in young horses with limited pasture access. Avoid breeding affected lines when possible. Signs include: symmetric ataxia and weakness (hind limbs worse); onset before 2 years; base-wide stance; hypermetric gait; no cranial nerve deficits
## Overview Equine herpesvirus-1 myeloencephalopathy (EHM) is the neurologic form of equine herpesvirus-1 infection. Neuropathogenic strains cause vasculitis and ischemic damage to the spinal cord. Typical signs are fever followed by acute hind-limb ataxia, urinary incontinence, and potentially rapid progression to recumbency. Outbreaks occur. ## Causes Neuropathogenic equine herpesvirus-1 (often associated with a specific DNA polymerase mutation). ## Diagnosis Clinical signs plus polymerase chain reaction testing of nasal swabs and blood, and cerebrospinal fluid analysis. ## Treatment Supportive care, anti-inflammatories, and nursing for recumbent horses. Antiviral drugs are sometimes used. Isolation is critical to prevent spread. ## Recovery and Prognosis Guarded. Horses that remain standing have a better chance. Recumbent horses have high mortality. ## Prevention Vaccination reduces respiratory disease and abortion but does not fully prevent neurologic disease. Biosecurity during outbreaks is essential. Signs include: fever followed by acute hind-limb ataxia and weakness; urinary incontinence; perineal hypalgesia; may progress to recumbency
## Overview Vertebral fracture or luxation with spinal cord compression most commonly occurs at C1-C2, C3-C4, or the thoracolumbar junction. Signs are acute severe ataxia or paralysis caudal to the lesion, neck pain with cervical fractures, and recumbency if the cord is transected. Deficits may be asymmetric. ## Causes Trauma, often falls or collisions. ## Diagnosis Neurologic examination and imaging. ## Treatment Strict stabilization. Corticosteroids are controversial. Surgery in selected cases. Complete transection is hopeless. ## Recovery and Prognosis Depends entirely on the severity of cord damage. ## Prevention Safe handling and environments. Signs include: acute severe ataxia or paralysis caudal to the lesion; neck pain with cervical fractures; recumbency if cord is transected; may be asymmetric
## Overview Equine motor neuron disease (EMND) is an acquired degeneration of lower motor neurons strongly associated with prolonged vitamin E deficiency (usually from long-term lack of green pasture). Affected horses show muscle wasting, trembling, weight shifting, and excessive lying down. Retinal lipofuscin deposits are a characteristic finding. ## Causes Chronic vitamin E deficiency in adult horses with limited or no access to pasture. ## Diagnosis Clinical signs, low serum vitamin E, muscle biopsy, and ophthalmic examination for retinal pigment. Electromyography supports the diagnosis. ## Treatment High-dose vitamin E supplementation. Some horses stabilize or improve mildly; others continue to decline. ## Recovery and Prognosis Guarded. Early supplementation offers the best chance of stabilization. Many horses are eventually euthanized. ## Prevention Ensure adequate vitamin E intake, especially for horses without pasture access. Signs include: generalized muscle wasting (especially epaxial and quadriceps); trembling; weight shifting; low head carriage; excessive recumbency; retinal lipofuscin
Wobbler syndrome, also known as cervical vertebral stenotic myelopathy, is a neurologic condition caused by compression of the spinal cord in the neck. It leads to progressive incoordination (ataxia), primarily in the hind limbs. There are two main forms: Type I (dynamic compression in young horses) and Type II (static compression in older horses due to osteoarthritis). ## What it is In Type I wobbler syndrome, developmental abnormalities of the cervical vertebrae cause narrowing of the vertebral canal and dynamic compression of the spinal cord during neck movement. It typically affects horses between 1 and 4 years of age, most commonly at C3 to C5. Type II wobbler involves static compression from osteoarthritic enlargement of the articular facets, usually affecting older horses at C5 to C7. Both forms result in damage to the spinal cord, leading to proprioceptive deficits and ataxia that is usually worse in the hind limbs. ## Signs and symptoms - Progressive hindlimb incoordination and ataxia - Wide-based stance and stumbling, especially when turning or going downhill - Toe dragging and difficulty backing - Neck stiffness or pain in some cases - In severe cases, weakness or falling - Symmetric or slightly asymmetric ataxia that is worse in the hind limbs than forelimbs - Positive cervical flexion test in many cases ## Causes and risk factors Type I wobbler is developmental and linked to rapid growth, genetic factors, and nutritional imbalances (especially copper deficiency or excess protein/calcium in young horses). Type II is associated with chronic wear and osteoarthritis of the cervical facet joints. Risk factors include large body size, rapid growth rates in young horses, and conformational issues that place abnormal stress on the neck. ## How it is diagnosed Diagnosis is based on clinical neurologic examination and confirmed with radiographs and myelography or MRI. Standing or recumbent radiographs can show vertebral canal narrowing or facet joint changes. Myelography or MRI provides the most accurate assessment of spinal cord compression. A neurologic grading system helps quantify the severity of ataxia. ## Treatment and management Treatment depends on the type, severity, and age of the horse. Conservative management includes stall rest, anti-inflammatory medication, and controlled exercise. For young horses with Type I, dietary management and restricted growth may help. Surgical options (ventral interbody fusion or dorsal laminectomy) are available for selected cases and can improve neurologic function in many horses. Prognosis varies widely depending on the severity and duration of compression before treatment. ## When to call the vet Contact your veterinarian promptly if your horse shows incoordination, stumbling, or difficulty backing or turning. Early diagnosis improves the chance of successful management or surgical intervention. ## Prevention For Type I wobbler in young horses, prevention focuses on balanced nutrition (avoiding excessive protein and calcium while ensuring adequate copper and other minerals) and avoiding overly rapid growth rates. Regular monitoring of at-risk young horses can help with early detection. ## Frequently asked questions **Can a horse with wobbler syndrome be ridden?** Many horses with mild to moderate signs can be ridden carefully after treatment, but those with severe ataxia are usually retired for safety reasons. **Is surgery always successful for wobbler syndrome?** Surgical success rates are good in appropriately selected cases, but results vary depending on the severity and chronicity of spinal cord damage. **Is wobbler syndrome hereditary?** There is a genetic component, especially in Type I. Breeding horses with wobbler syndrome or from lines with high incidence is generally discouraged. This information is for educational purposes only. Always consult with a licensed veterinarian for diagnosis and treatment of your horse. Signs include: Progressive hindlimb incoordination and ataxia; wide-based stance and stumbling, especially when turning or going downhill; toe dragging and difficulty backing; neck stiffness or pain in some cases; in severe cases, weakness or falling; symmetric or slightly asymmetric ataxia worse in hind limbs; positive cervical flexion test in many cases
Spinal cord compression (Wobblers syndrome), trauma, and infectious or inflammatory diseases can cause neurologic deficits. Diagnosis uses clinical examination and advanced imaging. Prognosis depends on the cause and severity.
Incoordination, weakness, or abnormal gait should be evaluated promptly. Protect the neck and back from trauma.
See the Spinal Cord on our interactive 3D horse model. Open 3D Model