A spur is most commonly a small metal device worn on the heel of a riding boot, used to give a horse precise, subtle cues during riding. But the word “spur” shows up across several fields, from medicine to engineering to railroads, each with a distinct meaning. The equestrian spur is the original and most widely searched, so let’s start there.
Spurs as a Riding Aid
In horseback riding, a spur is a short piece of metal that attaches to the back of a rider’s boot at the heel. Its purpose is to extend the rider’s leg so they can deliver clear, targeted signals to a horse’s sides. Spurs work alongside the rider’s natural aids (seat, legs, hands, and voice) to guide speed, lateral movement, and collection. They are not intended to cause pain or punish the horse.
Think of spurs as a communication tool, not a weapon. A well-trained rider uses a spur the way you might tap someone on the shoulder to get their attention: lightly and with purpose. The goal is to enhance the conversation between horse and rider, improving responsiveness without relying on force. Spurs are entirely optional, even at the highest levels of competitive riding. They don’t replace fundamental riding skills; they refine them.
Modern equestrian organizations take spur misuse seriously. The Fédération Equestre Internationale (FEI), the governing body for international horse sport, explicitly classifies excessive or persistent use of spurs as horse abuse under its regulations.
Types of Riding Spurs
Different spur designs serve different disciplines and skill levels. The variation comes down to the shape and length of the shank, which is the part that extends from the heel toward the horse.
- Prince of Wales: A short, angled shank that delivers gentle cues. Ideal for beginner to intermediate riders or sensitive horses.
- Rounded or knob: A ball-tipped shank that reduces the chance of accidentally delivering a harsh signal. Common in dressage or with young horses.
- Swan neck: A curved shank that allows riders with long legs, or those on smaller horses, to make clean contact without contorting their leg. Popular in dressage.
- Rowel: A small rotating wheel at the tip. When used correctly by experienced riders, the rolling motion can actually be gentler than a fixed point.
- Disc: A flat, spinning disc instead of a pointed tip. Provides gentle rolling contact and is often used in showjumping or eventing.
- Long or dressage shank: An extended shank for horses trained to respond to very nuanced signals. It lets the rider cue the horse without shifting their leg position.
Discipline matters when choosing a spur. Dressage riders typically opt for swan neck or long shank spurs for precision. Showjumpers lean toward disc or knob spurs for controlled, quick signals. Event riders sometimes switch between types depending on the phase of competition.
Bone Spurs in Medicine
In a completely different context, a bone spur (also called an osteophyte) is a smooth, bony growth that develops on the edge of a bone. Bone spurs form when the body tries to repair damage near a joint or where tendons and ligaments attach to bone. The body essentially lays down extra bone tissue as part of its healing process, like a bony scar. Bones that bear the most stress are the most common sites: the spine, heels, shoulders, and knees.
Many bone spurs cause no symptoms at all. Calcaneal spurs (heel spurs) have been found on X-rays in 10% to 63% of people who have zero heel pain. The spur itself isn’t always the problem. When bone spurs do cause trouble, it’s usually because they press against nearby nerves, tendons, or other bones, limiting range of motion or creating pain with movement.
Heel Spurs and Plantar Fasciitis
Heel spurs deserve special mention because they’re frequently linked with plantar fasciitis, the most common cause of chronic heel pain. These spurs develop at the bottom of the heel bone from repeated strain on the foot’s muscles and ligaments, stretching of the thick tissue band along the sole (the plantar fascia), and repeated tearing of the membrane covering the heel bone. On X-rays, they can stick out by as much as half an inch. Risk factors include obesity, rheumatoid arthritis, osteoarthritis, and age, since the plantar fascia loses flexibility over time.
Not every heel spur needs treatment. Research suggests that a spur smaller than 10 millimeters with a gradual angle is generally not a medical concern. For those with persistent, severe pain that doesn’t respond to stretching, orthotics, or physical therapy, surgery is an option. A 10-year retrospective study of heel spur surgeries found that 85% of patients were satisfied with their results, and 94% said they would recommend the procedure to others with severe heel pain.
Spur Gears in Machinery
In mechanical engineering, a spur gear is a wheel with straight teeth cut parallel to its axis. Spur gears are the simplest and most common type of gear, used to transmit rotational motion and power between two parallel shafts. When the teeth of two spur gears mesh together, one gear drives the other, transferring torque efficiently. By pairing gears of different sizes, engineers can increase or decrease speed and force as needed.
You’ll find spur gears inside gearboxes, conveyor systems, pumps, compressors, clocks, and countless other machines. Their straight-tooth design makes them easy to manufacture and reliable in operation, which is why they remain a foundational component across industries.
Other Uses of “Spur”
In railroads, a spur track is a short branch line that splits off from a main line to reach a specific industrial customer, like a factory or warehouse. It lets freight trains load or unload without blocking the main rail corridor.
In botany, a spur is a tube-shaped extension on certain flowers that stores nectar. Columbines (Aquilegia) are a classic example. The length of the spur often matches the tongue or proboscis length of the flower’s primary pollinator, a relationship that demonstrates coevolution. Charles Darwin famously predicted the existence of a moth with an extremely long tongue after observing an orchid with an unusually deep nectar spur, and the moth was eventually discovered.