Heel spurs are bony growths that develop on the calcaneus, the large bone forming the heel of your foot. They show up in two distinct locations: on the underside of the heel bone, where the plantar fascia and small foot muscles attach, and on the back of the heel bone, where the Achilles tendon connects. These two types have different names, different associated conditions, and sometimes different causes, but both are outgrowths of the same bone responding to chronic stress at the points where soft tissue anchors to it.
Plantar Calcaneal Spurs on the Underside of the Heel
The more common variety grows from the bottom surface of the calcaneus, specifically from a bump called the calcaneal tuberosity. Most of these spurs arise from the medial process of that tuberosity, which is the inner side of the heel bone closest to the arch of your foot.1PubMed Central. The plantar calcaneal spur: a review of anatomy, histology, etiology and key associations They can also form from the lateral (outer) process, though that is less typical. When you see an X-ray of a plantar heel spur, it looks like a small shelf or pointed projection jutting forward from under the heel bone toward the toes.
For decades, the standard explanation was that the plantar fascia, the thick band of tissue running from the heel to the toes, tugged on the bone so hard that the bone grew a spur in response. The reality is more nuanced. Dissection studies have found that plantar heel spurs actually sit within the origin of the small intrinsic muscles on the sole of the foot, not within the plantar fascia itself. The plantar fascia runs beneath the spur, attaching along its lower edge rather than pulling directly at the point where the spur grows.2The Foot. The inferior calcaneal spur—Anatomical and histological considerations Other anatomical studies have confirmed that spurs are generally not found in the direct line of pull from either the plantar fascia or the plantar muscles, suggesting the relationship between these structures and spur formation is not as straightforward as “pull equals growth.”3PubMed. Anatomic relationship of heel spur to surrounding soft tissues: greater variability than previously reported
Posterior Calcaneal Spurs at the Back of the Heel
The second type grows on the back of the heel bone, right where the Achilles tendon inserts. These are sometimes called dorsal calcaneal spurs or retrocalcaneal spurs, depending on their exact position. In anatomical studies, posterior spurs consistently appear at a spine-like ridge that separates the middle and lower attachment areas on the back of the calcaneus. The tips of these spurs tend to point in the direction of the Achilles tendon fibers, and superficial collagen bundles from the tendon insert directly into the spur, forming a transition zone of fibrocartilage around it.4Scientific Reports. Why heel spurs are traction spurs after all
Interestingly, in specimens with calcific Achilles tendinitis, the back surface of the spur itself was bare, with no tendon fibers attaching to it. Instead, the Achilles tendon attached between the spur and the posterior wall of the heel bone, and the spurs were positioned laterally at the lowest border of the tendon insertion.5PubMed. Achilles tendon insertion: an in vitro anatomic study Posterior spurs are closely linked to a condition called Haglund syndrome, which involves a triad of a bony prominence at the back of the heel, inflammation of the bursa between the tendon and bone, and degeneration within the Achilles tendon itself.6PubMed. The Heel Complex: Anatomy, Imaging, Pathologic Conditions, and Treatment If you have ever noticed a hard bump at the back of your heel that rubs painfully against the counter of your shoe, a posterior spur or Haglund deformity could be involved.
How Heel Spurs Actually Develop
Understanding where spurs sit matters partly because it changes how we think about why they form. The old traction theory said that repetitive pulling from the plantar fascia or Achilles tendon caused new bone to build up at the attachment site, like the body reinforcing a wall that keeps getting yanked on. That theory makes intuitive sense, and for posterior spurs it holds up reasonably well: the spur tips align with the Achilles tendon fibers, and small bony spurs at the Achilles insertion do appear to develop when ossification at one point on the tendon’s attachment outpaces the surrounding area.7Arthritis & Rheumatism. The mechanism of formation of bony spurs (enthesophytes) in the Achilles tendon
For plantar spurs, though, the picture is messier. Research on older adults found that these spurs may be more of an adaptive response to repeated vertical compression of the heel, the kind of impact loading you get from standing and walking, rather than a response to longitudinal pulling by the plantar fascia.8PubMed Central. Plantar calcaneal spurs in older people: longitudinal traction or vertical compression? This would explain why spurs do not always sit in the direct traction line of the fascia or muscles. It also helps explain something clinicians see all the time: plenty of people with large plantar heel spurs feel no pain at all, while others with severe heel pain show no spur on X-ray.
At the tissue level, spur development appears to progress in stages. First, degenerative changes show up at the attachment where the plantar fascia meets bone, with cartilage cell clusters and small fissures forming. Then the bone plate at that attachment thickens as a small spur takes shape. Finally, in larger spurs, the bone develops vertically oriented internal struts that buttress the growing projection. The spur itself grows through a combination of different bone-formation processes.9PubMed. Heel spur formation and the subcalcaneal enthesis of the plantar fascia
Can You Have Spurs in Both Locations at Once
Yes, and it is not rare. The two spur types are biomechanically connected. The Achilles tendon and the plantar fascia both anchor to the calcaneus and effectively work as parts of the same chain: tightness or increased tension in the Achilles tendon changes the loading pattern on the plantar fascia, and vice versa. Research on patients with insertional Achilles tendinitis has found a relationship between posterior and plantar calcaneal spurs, suggesting that increased tension throughout this chain can promote spur formation at both sites.10PubMed Central. A Radiographic Study of Biomechanical Relationship between the Achilles Tendon and Plantar Fascia In population data, roughly a third of people who have any spur at all have them at both locations.11PubMed Central. Changes in prevalence of calcaneal spurs in men & women: a random population from a trauma clinic
How Common They Are and Who Gets Them
Heel spurs become significantly more common as you age. In a study of over 1,300 lateral ankle X-rays, plantar spurs showed up in about 32% of all patients, and dorsal (posterior) spurs in about 13%. The incidence of both types climbed steadily with age. Plantar spurs peaked at roughly 42% in people over 70, while dorsal spurs peaked at about 22% in the 61-to-70 age group. Dorsal spurs were more common in women than men, though no significant gender difference showed up for plantar spurs.12PubMed Central. The age dependent change in the incidence of calcaneal spur
A separate population study found that about 38% of people had at least one spur of either type. Large spurs were concentrated in people between 40 and 79 years old, with no large plantar spurs found at all in people under 40. In women under 50, the prevalence of both spur types was significantly higher than in men of the same age, and there was a moderate positive correlation between having both plantar and Achilles spurs in younger women that was absent in younger men.11PubMed Central. Changes in prevalence of calcaneal spurs in men & women: a random population from a trauma clinic The takeaway is that heel spurs are extremely common in middle-aged and older adults, common enough that finding one on an X-ray does not, by itself, mean much about whether it is causing your symptoms.
Why a Spur on X-Ray Does Not Always Mean Pain
This is one of the most important things to understand about heel spurs and their location. Many people walk around with sizable bony projections under or behind their heel and feel nothing at all. When heel pain does occur in the presence of a spur, the spur itself may not be the primary pain generator. The pain more often comes from the inflamed soft tissues around it: a thickened and irritated plantar fascia, a swollen bursa behind the heel, or a compressed nerve.
That said, the presence of a plantar spur is not meaningless. People with chronic plantar heel pain are significantly more likely to show a spur on X-ray than people without heel pain.13PubMed Central. Diagnostic imaging for chronic plantar heel pain: a systematic review and meta-analysis The spur likely reflects the same chronic mechanical stress that produced the soft-tissue damage, so it serves as a marker of how long and how severely the heel has been loaded. Researchers have even classified plantar spurs into distinct types based on their shape and orientation, and the type of spur appears to correlate with the severity of accompanying plantar fasciitis, with more inflammatory cells found in the spur tissue of the more severe type.14PubMed. Classification of Calcaneal Spurs and Their Relationship With Plantar Fasciitis
Nerve Entrapment Near the Spur
One underappreciated source of heel pain related to spur location involves a small nerve called the inferior calcaneal nerve, commonly known as Baxter’s nerve. This is the first branch of the lateral plantar nerve, and it runs along the inside of the heel in close proximity to where plantar spurs form. When a spur grows in that area, or when the surrounding tissues swell, the nerve can become compressed. The result is pain that mimics plantar fasciitis but does not always respond to the same treatments.15PubMed Central. Plantar Fasciitis with Chronic Baxter’s Neuropathy Causing Hindfoot Pain – A Case Report
When surgery is performed for chronic heel pain that hasn’t responded to conservative treatment, releasing the tissue around Baxter’s nerve is a routine part of the procedure. If an impinging spur or tight plantar fascia is identified as the cause of nerve compression, partial removal of the spur or release of the fascia is done to decompress the nerve.16PubMed. Heel pain–operative results This is worth knowing because people whose heel pain is burning, tingling, or radiating, rather than the classic “stepping on a stone” feeling, may have nerve involvement rather than purely fascial inflammation.
Conditions That Make Spurs More Likely
Heel spurs are associated with a cluster of systemic and mechanical conditions. Obesity and excess body weight are major contributors, for the simple reason that heavier body weight increases the compressive load on the heel with every step. Plantar fasciitis is the condition most often seen alongside plantar spurs, though the relationship goes both ways and the spur is probably a consequence of the same mechanical overload rather than the cause of the fasciitis. Inflammatory joint diseases, including rheumatoid arthritis, ankylosing spondylitis, and reactive arthritis, are also linked to spur formation.17PubMed Central. Plantar Fasciitis With a Calcaneal Spur
Gout is another condition worth mentioning. The metabolic disruptions that come with gout, particularly impaired microvascular blood flow and localized low oxygen levels at tendon and ligament attachment sites, appear to promote calcification. In gout patients, the presence of metabolic comorbidities roughly tripled the odds of developing a moderate-to-large calcaneal spur.18Turkish Journal of Medical Sciences. The frequency of Achilles and plantar calcaneal spurs in gout patients Flat feet and high arches are also mentioned as risk factors, presumably because both alter the way force distributes through the heel during walking.19PubMed Central. Calcaneal Spurs: A Potentially Debilitating Disorder
How Location Shapes Treatment
Because most heel spur pain comes from the surrounding soft tissue rather than the spur itself, treatment almost always starts with conservative measures aimed at reducing inflammation and correcting the mechanical stress that produced the problem. For plantar spurs, this typically means some combination of rest, stretching, cushioned or supportive footwear, and orthotic insoles. A randomized trial found that both custom insoles and minimalist flexible footwear significantly reduced pain and improved foot function in women with calcaneal spurs after six months, along with reduced foot pronation, which is the inward rolling that places extra stress on the medial heel.20PubMed Central. Effectiveness of mechanical treatment with customized insole and minimalist flexible footwear for women with calcaneal spur: randomized controlled trial
One clinical approach to heel spur syndrome treats it in two phases. The first phase uses an orthotic that both controls abnormal pronation and cushions the inflamed area. Once the acute inflammation settles, a second, more rigid orthotic is introduced to maintain proper foot mechanics long-term and prevent recurrence.21Clinics in Podiatric Medicine and Surgery. History and Mechanical Control of Heel Spur Pain This two-stage strategy reflects the idea that the spur itself is usually not the problem; it is the biomechanical pattern that caused the spur and the inflammation around it.
For posterior spurs, treatment often focuses on reducing friction and pressure at the back of the heel. Shoe modifications, heel lifts, Achilles stretching, and sometimes a period of immobilization in a walking boot all get used. If a Haglund deformity is present, open-backed shoes can provide immediate relief by eliminating the contact that provokes pain.
When Surgery Targets the Spur Directly
Surgery is reserved for people whose pain has not responded to months of conservative treatment. For plantar heel spurs, the most common procedures involve endoscopic spur removal combined with partial release of the plantar fascia. The spur is shaved down or excised through small incisions, and the tight band of the fascia is released to reduce tension on the heel bone. Comparing two different endoscopic approaches, both a medial dual-incision technique and a combined medial-lateral approach produced significant improvement in pain scores and functional outcomes after surgery, though the medial-only approach was faster to perform.22PubMed Central. Comparison of Short-Term efficacy between medial and lateral dual incision approach and medial dual incision approach for endoscopic spur resection combined with plantar fascia release in the treatment of heel pain syndrome
For posterior spurs associated with Haglund syndrome or insertional Achilles tendinitis, surgery typically involves removing the bony prominence, debriding any damaged tendon tissue, and sometimes reattaching the Achilles tendon if a significant portion had to be detached during the procedure. Recovery from posterior heel surgery tends to be longer than plantar surgery because of the Achilles tendon’s involvement and slower healing capacity.
Heel Pain in Children Is Usually Not a Spur
If your child complains of heel pain, a spur is almost certainly not the cause. In growing children and adolescents, the calcaneus has a growth plate at the back of the heel called the calcaneal apophysis, and this area is vulnerable to a condition called Sever’s disease, or calcaneal apophysitis. It is an overuse injury caused by repetitive stress on the growth plate, typically in active kids between the ages of 8 and 14. The pain is at the back of the heel, which can sound like a posterior spur, but X-rays will show an open growth plate rather than a bony spur. True calcaneal spurs are essentially an adult phenomenon. Large plantar spurs have not been found in people under 40 in population studies, and the condition becomes progressively more common with age.11PubMed Central. Changes in prevalence of calcaneal spurs in men & women: a random population from a trauma clinic A child with heel pain needs a different workup and a different set of treatments entirely.
The Spur You Can Feel Versus the Spur on the X-Ray
Posterior calcaneal spurs or Haglund deformities can sometimes be felt or even seen as a hard bump at the back of the heel. Plantar spurs, on the other hand, are buried under the fat pad of the heel and are essentially never palpable. You cannot feel a plantar spur by pressing on the bottom of your foot; what you are feeling when you press on a tender spot under the heel is the inflamed fascia or compressed soft tissue, not the bony projection itself. This matters because people sometimes assume the sharp, localized pain under their heel means they are “stepping on” the spur. In reality, the spur points forward along the foot, not straight down into the ground, and the heel’s fat pad sits between the spur and the walking surface. The pain comes from the tissue around the spur, not from the spur poking into the ground.
Knowing where heel spurs actually sit on the bone, which structures they develop within, and how they relate to the surrounding soft tissue is genuinely useful. It explains why two people with identical-looking spurs on X-ray can have completely different experiences, one in pain and one oblivious. It explains why treatments focus on the fascia, the tendon, the nerve, and the biomechanics rather than on grinding down the bony growth. And it explains why the spur itself, despite being the most visible feature on an X-ray, is usually a bystander rather than a villain.