Vertebra thoracica 6
Sixth thoracic vertebra. The spinous process remains tall but begins to decrease in height caudal to the withers summit.
Origin: N/A (bone)
Insertion: N/A (bone)
Action: Anchor the ribs; form the withers; serve as attachment points for the powerful back and shoulder muscles; support the saddle area
Thoracic vertebrae are assessed with standing lateral radiography and nuclear scintigraphy. Kissing spines are common in the T13-T18 region.
Fracture of the dorsal spinous processes of the withers, usually from falling or flipping over. Can also occur from ill-fitting saddles creating pressure points.
Kissing spines, also known as overriding dorsal spinous processes, occur when the bony projections along the top of the horse's spine touch or overlap, causing pain and inflammation. This condition mo
T6 sits roughly beneath the saddle's pommel area. Kissing spines commonly affects T13-T18 but saddle fit issues can cause pain at T6. Proper saddle fitting and regular back evaluations help prevent thoracic problems. View in 3D at /explore.
Fracture of the dorsal spinous processes of the withers, usually from falling or flipping over. Can also occur from ill-fitting saddles creating pressure points. Signs include: Severe pain and swelling over the withers; inability to be saddled; fistulous withers if secondary infection develops; confirmed on radiographs.
Kissing spines, also known as overriding dorsal spinous processes, occur when the bony projections along the top of the horse's spine touch or overlap, causing pain and inflammation. This condition most commonly affects the thoracolumbar region (T13 to L2) and is seen on radiographs in 30 to 40% of horses, though not all show clinical signs. It is a frequent cause of back pain and poor performance in sport horses. ## What it is The dorsal spinous processes are the upward-pointing bony projections of the vertebrae. In kissing spines, these processes are too close together and impinge on each other during movement, leading to bone remodeling, inflammation of the interspinous ligaments, and pain. The condition is often associated with poor posture, weak core muscles, or conformational factors that increase extension of the back. While many horses have radiographic changes without pain, clinical kissing spines cause significant discomfort, especially under saddle. ## Signs and symptoms - Back pain or sensitivity when pressure is applied along the spine - Dipping away from pressure or hollowing the back under rider - Bucking, rearing, or resistance to collection - Poor performance or unwillingness to go forward - Muscle atrophy along the topline - Reluctance to canter or perform lateral movements - Extreme sensitivity at specific vertebral levels during grooming or saddling - Cross-cantering or difficulty maintaining a consistent gait ## Causes and risk factors Kissing spines develop from a combination of conformational, biomechanical, and management factors. Risk factors include weak abdominal and back muscles, repetitive extension of the spine (common in jumping and dressage), poor saddle fit, and genetic predisposition. Horses with long backs or weak toplines are more susceptible. The condition can also develop secondary to other sources of pain that cause the horse to hollow its back. ## How it is diagnosed Diagnosis combines clinical examination, palpation of the back, and imaging. Radiographs are the primary tool and show the proximity or overlap of the spinous processes. Nuclear scintigraphy (bone scan) can help identify active inflammation. Ultrasound evaluates the interspinous ligaments and soft tissues. Local anesthesia of the affected interspinous spaces is often used to confirm that the kissing spines are the source of pain. ## Treatment and management Treatment options range from conservative to surgical. Conservative management includes physiotherapy, core strengthening exercises, shockwave therapy, mesotherapy, and anti-inflammatory medication. Interspinous ligament injections or corticosteroid injections into affected spaces can provide relief. In refractory cases, surgical options such as interspinous ligament desmotomy or partial resection of the spinous processes are used with good success rates in appropriately selected horses. Saddle fit evaluation and rehabilitation are essential components of long-term management. ## When to call the vet Contact your veterinarian if your horse shows signs of back pain, resistance under saddle, or performance issues that do not resolve with basic management changes. Early diagnosis and a multimodal treatment plan offer the best chance of returning the horse to comfortable work. ## Prevention Prevention focuses on maintaining strong core and back muscles through appropriate conditioning and avoiding repetitive spinal extension without adequate strength. Regular saddle fit checks, good footing, and prompt attention to any signs of back discomfort help reduce risk. Horses with conformational risk factors benefit from proactive core strengthening programs. ## Frequently asked questions **Do all horses with kissing spines on X-rays have pain?** No. Many horses have radiographic changes without clinical signs. Diagnosis requires correlation with clinical findings and response to local anesthesia. **Can kissing spines be cured?** Surgical treatment can provide long-term improvement in many horses. Conservative management can control symptoms but may not eliminate the underlying bony changes. **Is surgery always necessary?** No. Many horses respond well to physiotherapy, injections, and rehabilitation. Surgery is usually reserved for cases that do not improve with conservative treatment. This information is for educational purposes only. Always consult with a licensed veterinarian for diagnosis and treatment of your horse. Signs include: Back pain or sensitivity when pressure is applied along the spine; dipping away from pressure or hollowing the back under rider; bucking, rearing, or resistance to collection; poor performance or unwillingness to go forward; muscle atrophy along the topline; reluctance to canter or perform lateral movements; extreme sensitivity at specific vertebral levels during grooming or saddling; cross-cantering or difficulty maintaining a consistent gait
Thoracic vertebrae are assessed with standing lateral radiography and nuclear scintigraphy. Kissing spines are common in the T13-T18 region.
T6 sits roughly beneath the saddle's pommel area. Kissing spines commonly affects T13-T18 but saddle fit issues can cause pain at T6. Proper saddle fitting and regular back evaluations help prevent thoracic problems. View in 3D at /explore.
See the Thoracic Vertebra (T6) on our interactive 3D horse model. Open 3D Model