Merck Manual

Please confirm that you are a health care professional

honeypot link
Pet Owner Version

Disorders of the Back in Horses


Peter Clegg

, MA, Vet MB, DipECVS, PhD, MRCVS, Veterinary Teaching Hospital, School of Veterinary Sciences, University of Liverpool

Reviewed/Revised Apr 2019 | Modified Oct 2022
Topic Resources

Disorders of the back include fractures, muscle and ligament strain, degenerative diseases, kissing spines syndrome, and injuries to the sacroiliac junction (the joint between the back and pelvis). Back problems are a major cause of poor performance and gait abnormalities in sport and race horses, and definitive diagnosis of the cause can be a challenge.


Multiple fractures in the upper portions of the vertebrae (called the spinous processes) of the withers are sometimes seen in young horses that have reared up and fallen over backward. After the initial pain and local reaction have subsided, the horse usually recovers with no permanent effect on performance. A persistent swelling over the withers, however, may require use of a special saddle. Occasionally, other spinal fractures occur, and their presence can be confirmed with x-rays. The signs in these cases are variable.

Fractures of the main body of the vertebrae are more serious. Such fractures usually result from a bad fall entailing a somersault. Damage to the spinal cord may cause complete or partial paralysis of the limbs. The outlook for recovery is grave.

Muscle and Ligament Strain

Damage to the soft tissues is the most common cause of back soreness in the horse. This mostly involves the group of muscles along the back. Usually, all or parts of these muscles are strained while the horse is being ridden. The principal sites of damage are located just in front of and behind the saddle area. Signs include alteration of the horse’s performance and acute back pain. Most of these injuries respond to rest and physiotherapy, although several weeks may be needed for full recovery ( see also Muscle Disorders in Horses Muscle Disorders in Horses Myopathies are diseases that primarily cause damage to muscles. They may be present at birth (congenital) or occur due to nutritional imbalances, injury, or ingestion of a poisonous substance... read more ).

Another fairly common site of soft-tissue damage is the ligament that runs down the middle of the back. Signs of damage to this ligament typically persist longer, and the chances of complete recovery are not as good as for the uncomplicated muscle strains.

Degenerative Diseases of the Spine

Arthritis occurs in the joints of the back as it does elsewhere in the horse’s body. Ultrasound is most useful for identifying the affected joints and for targeting treatment. Ongoing treatment at regular intervals (ie, 2-4 times per year) is usually required to enable affected horses to perform. Injection, shockwave therapy, massage, acupuncture and chiropractic treatments may be applied, individually or in combination.

Kissing Spine Syndrome

The spinous processes are the bony structures that protrude upwards from the body of vertebrae. You can feel their upper points in the midline of the back between the large back muscles. They do not normally touch each other; however, with kissing spines syndrome, 2 or more do. This may be partially due to the effects of bearing a rider. When this occurs beneath the saddle area, some horses develop back pain. The condition may also cause a local bone reaction, small bone cysts, and false joint formation. Diagnosis can be aided by injection of local anesthetic into the affected spaces between the spinous processes. Many cases respond to rest and physiotherapy, but persistent cases may require surgically removing one or more of the tops of the spinous processes to relieve the crowding of the spines.

Vertebrae, horse

Vertebrae, horse

Sacroiliac Injury (Dislocation, Strain, Arthrosis, Hunter’s Bumps)

Acute and severe strain of the sacroiliac ligaments typically results from an injury. It can produce severe pain in the pelvic or sacroiliac region and lameness in the hindlimbs. Longterm sacroiliac strain is a cause of back soreness. It may indicate incomplete healing or reinjury of an earlier strain. Sacroiliac injury may affect a horse’s performance, producing intermittent, often shifting, hindlimb lameness. The action of the hindlimbs may be reduced, and the horse may drag the toe of one or both hooves.

Sacroiliac injury is common in Standardbreds and hunter-jumper horses. It is sometimes confused with longterm stifle problems. Usually, the hindquarter muscles will be poorly developed and, when viewed from behind, the hindquarters may be asymmetrical. This may be due to some tilting or rotation of the pelvis or muscle wastage of one quarter, or both. In the early stages of injury, pressure applied to the area may cause pain. The horse may hold its tail slightly to the side and be reluctant to bend its back. If a diagnosis is made early and the horse is rested long enough to allow complete healing of the damaged ligaments (6 to 9 months), recovery can occur. However, Standardbreds usually do not compete well following a sacroiliac injury. Horses with lasting injuries continue to perform poorly despite rest and anti-inflammatory medication.

For More Information

quiz link

Test your knowledge

Take a Quiz!