Page 171 - Speedhorse February 2020

EQUINE HEALTH
The two long and slender splint bones, which are finger size in diameter, are attached to each side of the cannon bone toward the rear.
SPLINTS
Splint bones are most familiar to horsemen in their role of creating “splints”—painful swellings that may or may not become bony enlargements. Mild irritations may cause heat and swelling, mild lameness, and then resolve. More severe cases generally produce new bone growth, and a permanent lump. After the inflammation subsides, the swelling becomes smaller and firmer. In early stages, most of the enlargement is due to inflammation, but once the area heals, all that remains is the smaller bone formation.
“From a clinical perspective, splints are seen most often in younger horses, especially when they start in training,” says Baxter. Young horses with poor front limb conformation (more stress on one side or the other) may disrupt the interosseous ligament before it stabilizes, especially if the horse is overworked.
Subsequent bony enlargements may vary from pea-size to as large as a chicken egg. A young horse in training may “pop a splint” with sudden swelling, inflammation and lameness—or may develop a bony enlargement without any history of lameness. The bony lump is usually just a blemish after the inflammatory stage is past.
“Splints are definitely more common on the inside splint bone, and many of these are fairly proximal (close to the knee). The typical location is often about 6 to 7 centimeters (2.5 to 3 inches) below the knee,” he says. Due to
the shape and angle of the splint bone, the top and inside of the inner splint bone take more weight and stress than does the outer splint bone. The more weight applied to the top of the inner splint bone - as from offset cannons, often called “bench knees,” with the cannons too far to the outside rather than located directly under the knee joint - the more risk
for splints. The inner splint is also more prone to injury because the inside of the leg usually takes more weight than the outside of the limb.
“People talk about the tearing of the interosseous ligament, which attaches the
splint bone to the lining of the cannon bone, and I think this can be confused with the true interosseous ligament, which is the suspensory,” says Baxter.
“The suspensory ligament is between the splint bones attached to the back of the cannon bone, versus the much smaller interosseous ligament between the axial border of the
splint bone and the back of the cannon bone. What most people refer to when they talk about splints is the actual tearing of that small ligament. Depending on the severity, this may involve just a little bit of local tearing—which can be resolved/healed by icing and wrapping and taking the horse out of work. In these instances, you usually don’t get any bony growth,” Baxter explains.
Bones are covered with a thin membrane (the periosteum), which protects and nourishes the bone, serves as an anchor for tendons
Scapula
Humerus Point of elbow
Radius
Pisiform bone Knee
Cannon bone Splint bones
Sesamoid bones
The first step for treatment when the horse first goes lame and has heat and swelling in that area, is to decrease the inflammation by cold hosing, placing ice on the area, using non- steroidal anti-inflammatory therapy and/or wrapping the leg
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