Bone spurs in the foot develop when your body lays down extra bone tissue in response to pressure, friction, or damage. They’re one of the most common skeletal changes in adults over 40, and they form in predictable locations: the bottom of the heel, the back of the heel where the Achilles tendon attaches, and the base of the big toe. Each location has its own set of triggers, but the underlying process is the same.
How Your Body Builds Bone Spurs
When bone or the soft tissue surrounding it is stressed or damaged, your body treats it like an injury that needs repair. Bone-building cells ramp up their activity and deposit new bone tissue at the site of stress, essentially forming a bony scar. This process, called osteophytosis, is your skeleton’s attempt to reinforce an area that’s under strain.
At the cellular level, mechanical pressure triggers bone-building cells to absorb more glucose, which sets off a chain reaction that promotes new bone growth. Specifically, repeated stress suppresses a protein that normally keeps bone formation in check, allowing bone-building signals to run unchecked. This is why bone spurs tend to appear at high-stress points: the underside of the heel where your weight lands with every step, or where tendons pull on bone thousands of times a day.
Plantar Fasciitis and Heel Spurs
The most common bone spur in the foot forms on the bottom of the heel bone, and it’s closely tied to plantar fasciitis. The plantar fascia is a thick band of tissue that runs along the sole of your foot from heel to toes. When it’s chronically inflamed or strained, the constant pulling at its attachment point on the heel bone stimulates new bone growth. In one study, 89% of patients with plantar fasciitis had a visible heel spur on X-ray.
That doesn’t mean the spur itself is causing the pain. Many people have heel spurs that show up on imaging but cause no symptoms at all. The pain associated with plantar fasciitis comes primarily from the inflamed tissue, not the bony growth. Still, the two conditions share the same root causes: excess body weight, prolonged standing or walking on hard surfaces, shoes with poor cushioning, flat feet or overpronation, and limited ankle flexibility. Age plays a major role too. Degenerative changes in the fat pad that cushions your heel make it less effective as a shock absorber over time, increasing the mechanical load on the fascia and the bone beneath it.
Achilles Tendon and Back-of-Heel Spurs
Bone spurs also form at the back of the heel where the Achilles tendon attaches. This spot absorbs enormous force every time you push off the ground while walking or running. When the Achilles tendon is chronically tight or inflamed, the repeated pulling on the heel bone triggers the same bone-building response.
A related condition called Haglund’s deformity produces a visible bony bump at this same attachment point. Tight Achilles tendons are a common contributor, along with shoes that press against the back of the heel (rigid-backed dress shoes, ice skates, or high heels). Runners and people who suddenly increase their activity level are particularly susceptible because the tendon’s attachment site hasn’t had time to adapt to the increased load.
Big Toe Bone Spurs
The joint at the base of the big toe is another frequent site for bone spurs. Every step you take places a force equal to roughly twice your body weight on this joint. Over years, that repetitive loading wears down the cartilage that cushions the joint surfaces, and your body responds by building bone spurs around the edges.
This condition, known as hallux rigidus, progressively limits how far you can bend your big toe. It’s graded on a scale from 0 to 4 based on how much range of motion you’ve lost, from 10% to 20% in early stages up to near-complete stiffness in advanced cases. Pain and stiffness tend to worsen gradually. People who overuse this joint through sports, physical jobs, or hobbies that involve repetitive pushing off are at higher risk, as are those who’ve had injuries like stubbing the toe hard or spraining it (turf toe). Having longer-than-average foot bones also increases the mechanical disadvantage at this joint.
Osteoarthritis and Joint Degeneration
Osteoarthritis is the single most common driver of bone spurs across the entire body, and the foot is no exception. The midfoot joints, ankle, and toe joints are all vulnerable. As cartilage breaks down from years of use, the exposed bone surfaces experience more friction and pressure. Your body compensates by building extra bone at the joint margins, which is why bone spurs and arthritis are so tightly linked.
This process tends to be self-reinforcing. As spurs grow, they can alter the mechanics of the joint, causing uneven loading that accelerates further cartilage loss and prompts more spur formation. In the foot, this is especially problematic because even small changes in joint shape can alter your gait, shifting stress to other parts of the foot.
Foot Structure and Gait Problems
The way your foot is built and how you walk directly influence where bone spurs are likely to develop. Overpronation, where your foot rolls inward excessively with each step, flattens the arch and redistributes mechanical stress in ways the foot wasn’t designed to handle. Over time, this can contribute to bunions (bony growths at the base of the big toe), heel spurs, and stress at tendon attachment points throughout the foot.
High arches create the opposite problem. Instead of distributing force across the full sole, a high-arched foot concentrates pressure on the heel and ball of the foot, overloading those areas. People with either structural pattern are more likely to develop bone spurs than those with neutral foot mechanics, especially if they spend long hours on their feet or participate in high-impact activities without supportive footwear.
Age, Weight, and Systemic Conditions
Bone spurs in the foot become dramatically more common with age. They’re essentially nonexistent in people under 20. By the 40s, roughly 30% to 40% of adults have at least a small plantar spur visible on X-ray. Prevalence continues to climb through the 60s and 70s, where large heel spurs peak at around 14% to 20% of the population. After 80, prevalence actually drops, likely reflecting changes in activity level and survival bias in study populations.
Excess body weight is one of the strongest modifiable risk factors. More weight means more force on the heel, the plantar fascia, the Achilles tendon, and the toe joints with every single step. This is compounded by the fact that obesity is associated with low-grade systemic inflammation, which may accelerate the degenerative changes that trigger spur formation.
A condition called diffuse idiopathic skeletal hyperostosis (DISH) can also cause bone spurs in the feet and heels. DISH involves excess bone growth into ligaments and tendons throughout the body, and it frequently affects the heel and ankle. It overlaps heavily with metabolic syndrome: high blood sugar, high cholesterol, elevated uric acid, and obesity all increase the risk. People with DISH often develop calcification at multiple tendon attachment points, not just in the foot but across the skeleton.
How Bone Spurs Are Found
Most bone spurs in the foot are discovered on standard X-rays, which clearly show bony outgrowths at the heel, toe joints, or midfoot. Many are found incidentally, meaning you went in for foot pain or an unrelated injury and the spur showed up on imaging without being the source of your symptoms.
X-rays are usually sufficient for diagnosis. MRI is occasionally used when a doctor needs to evaluate the soft tissue around the spur, such as the plantar fascia, Achilles tendon, or joint cartilage. MRI can reveal tears, inflammation, and cartilage damage that X-rays miss, which helps determine whether the spur or the surrounding tissue is actually responsible for your pain. In many cases, the spur itself is an incidental finding, and the real problem is the soft tissue damage that triggered the bone growth in the first place.