Soreness at the back of the heel almost always traces to one of a handful of conditions affecting the Achilles tendon, the bursa tucked behind it, or the bone they attach to. The most common culprit in adults is insertional Achilles tendinopathy, a degenerative process right where the tendon meets the heel bone. But bony prominences, inflamed bursae, growth-plate irritation in kids, and even certain medications can produce the same nagging ache. Identifying which structure is angry matters, because the fixes differ depending on the cause.
A Crowded Neighborhood of Tissue
The back of your heel packs a surprising amount of anatomy into a small space. The Achilles tendon fans out and anchors into the calcaneus, the large heel bone. Sandwiched between the tendon and the bone sits the retrocalcaneal bursa, a small fluid-filled cushion that prevents friction during walking. Research on cadaveric specimens found that this bursa is present in everyone and always contains a synovial fold that sits between the tendon’s front surface and the back of the calcaneus. The floor of the bursa is lined with a thin layer of fibrous cartilage where the tendon attaches, and the bony surface behind it has an exceptionally thin cortical shell.1PubMed. Clinical anatomy of the retrocalcaneal bursa That thin bone and tight arrangement of soft tissue help explain why this spot is so vulnerable. Any swelling, extra bone growth, or tendon thickening in such cramped quarters quickly becomes painful.
Insertional Achilles Tendinopathy
This is the most frequent source of posterior heel pain in active adults. Insertional Achilles tendinopathy is a degenerative condition marked by pain, swelling, and stiffness right at the point where the tendon meets the calcaneus. The problem is driven by excessive mechanical loading and compressive forces at the enthesis, which is the specialized zone where tendon transitions into bone. Over time, the tendon tissue in this area undergoes degeneration rather than true inflammation, and it can develop calcification within its fibers.2PubMed Central. Current Concepts Review Update: Insertional Achilles Tendinopathy
You feel it most when starting to walk after sitting for a while, or when pushing off the ground during running. Squeezing the back of the heel where the tendon meets bone reliably reproduces the pain. Ultrasound studies comparing people with insertional versus midportion Achilles tendinopathy (the kind that hurts a few inches above the heel) found that the insertional group had significantly thicker tendons at the calcaneus on the injured side and a much higher rate of calcification and bony changes compared to the midportion group.3PubMed Central. Differences at the Achilles Insertion Between Adults with Insertional and Midportion Achilles Tendinopathy as Observed Using Ultrasound That distinction matters because the two conditions respond differently to treatment. What works well for midportion pain, such as aggressive eccentric heel drops off a step, can actually aggravate the insertional type by increasing compression at the bone.
Haglund’s Deformity and Retrocalcaneal Bursitis
If the bony bump at the back of your heel seems larger than normal and shoes press into it painfully, you may be dealing with Haglund’s deformity. This is an enlargement of the posterosuperior corner of the calcaneus, the bony ridge right where the Achilles tendon attaches. The enlarged bump rubs against rigid shoe counters, especially in dress shoes, heels, or stiff boots, irritating the overlying soft tissue and causing pain and visible swelling.4PubMed Central. Haglund’s Syndrome: A Commonly Seen Mysterious Condition
Haglund’s deformity and retrocalcaneal bursitis frequently travel together. The excessive bony prominence pinches and inflames the retrocalcaneal bursa, and once that bursa swells it presses against the Achilles tendon from the front. Rigid and prominent heel counters with higher heels worsen the impingement on the soft tissues overlying the prominence.5Orthopedic Clinics of North America. Haglund’s Deformity and Retrocalcaneal Bursitis The result is a cycle of mechanical irritation: the bone pushes the bursa into the tendon, shoes push against the bone, and everything stays angry. People sometimes call this “pump bump” because the rigid heel counters of pump-style shoes are a classic trigger.
Posterior Heel Pain in Children and Teenagers
If your child complains that the back of the heel hurts after sports, the likely explanation is Sever’s disease, or calcaneal apophysitis. This is the leading cause of heel pain in kids between roughly 8 and 15 years old.6Advanced Emergency Nursing Journal. Sever’s Disease (Calcaneal Apophysitis) It happens because the calcaneus is still growing at that age and has an open growth plate at its back end. Repetitive stress from running, jumping, and court sports puts strain on that growth plate before it has fully hardened.
Sever’s disease can show up in one heel or both. It is widely considered an overuse injury, though the exact mechanism is not entirely nailed down. The prevailing view is that the combination of a still-soft growth plate and the pull of the Achilles tendon creates microstress that inflames the area.7PubMed Central. Sever’s Disease of the Pediatric Population: Clinical, Pathologic, and Therapeutic Considerations The good news is that it resolves on its own once the growth plate fuses, usually by the mid-teens. In the meantime, activity modification, heel cups, and stretching keep it manageable. Unlike adult posterior heel conditions, Sever’s disease does not cause lasting damage.
Bone Spurs at the Insertion
Posterior calcaneal spurs, the bony projections that grow where the Achilles tendon attaches, are a related but distinct source of pain. These spurs form over time in response to sustained traction forces from the tendon pulling on the bone. They are common findings on X-rays of people with insertional Achilles tendinopathy, and in many cases they exist without causing symptoms at all. The trouble starts when a spur grows large enough to press into surrounding soft tissue or, in some cases, when the spur itself fractures from the chronic pulling forces. Because these are essentially stress fractures caused by sustained traction, spur fractures may need surgical intervention.8World Journal of Orthopedics. Characterizing posterior calcaneal spur fractures in insertional Achilles tendinopathy: A case control study
Not every spur you see on an X-ray is the source of your pain. Imaging studies routinely find heel spurs in people who have no symptoms. The clinical decision is whether the spur is merely present or actively contributing to the problem, and that judgment usually comes from correlating the spur’s location and size with the exact spot that hurts.
Less Obvious Causes
Systemic Inflammatory Disease
Sometimes posterior heel pain is the first sign of something happening throughout the body. In conditions like ankylosing spondylitis and psoriatic arthritis, the immune system targets entheses, the spots where tendons and ligaments attach to bone. The Achilles insertion at the heel is one of the most commonly affected sites. Clinical trials studying these conditions specifically enrolled patients who had both clinical and MRI-confirmed heel enthesitis, which gives a sense of how routinely the heel is involved.9PubMed Central. Achilles tendon enthesitis evaluated by MRI assessments in patients with axial spondyloarthritis and psoriatic arthritis: a report of the methodology of the ACHILLES trial If your heel pain showed up alongside low back stiffness that is worse in the morning, skin plaques, or pain in other tendons, it is worth mentioning to your doctor. The treatment in these cases targets the underlying disease rather than just the heel.
Medications That Weaken the Tendon
A class of antibiotics called fluoroquinolones (ciprofloxacin, levofloxacin, and similar drugs) has a well-documented association with Achilles tendon problems. A systematic review and meta-analysis found that fluoroquinolone use roughly quadrupled the odds of developing Achilles tendinopathy and about two and a half times the odds of Achilles tendon rupture.10PubMed. Fluoroquinolones and the risk of tendon injury: a systematic review and meta-analysis An earlier systematic review noted that the risk is highest within the first month after starting the medication.11PubMed. Tendon Injury and Fluoroquinolone Use: A Systematic Review If your heel pain appeared shortly after taking one of these antibiotics, that connection is worth flagging. Older adults and people on corticosteroids at the same time appear to face higher risk.
Nerve Entrapment
The sural nerve runs along the outer aspect of the ankle and the back of the heel. When it becomes compressed or irritated, it can produce pain that mimics Achilles tendon problems closely enough to fool both patients and clinicians. Sural nerve compression is frequently misdiagnosed as recurrent tendinopathy, prompting athletes to undergo tendon-focused treatments that never resolve the issue.12PubMed Central. Overview of nerve entrapment syndromes in the foot and ankle Clues that the nerve is involved rather than the tendon include burning or tingling sensations alongside the ache, pain that runs along the outer edge of the foot, and tenderness that doesn’t quite line up with the Achilles tendon itself. If standard tendon treatments aren’t helping, nerve entrapment should be on the differential.
Getting the Right Diagnosis
A hands-on clinical exam is still the starting point: where exactly does it hurt, what movements reproduce it, and does squeezing the tendon or pressing on the bone trigger the pain? But imaging can sharpen the picture considerably. Ultrasound has proven to be both sensitive and specific for differentiating the common causes of heel pain. A comparative study found that adding shear wave elastography to standard ultrasound boosted diagnostic accuracy for Achilles tendinopathy to nearly 98%, with very high sensitivity and specificity.13PubMed Central. Ultrasound imaging and shear wave elastography for the differential diagnosis of heel pain: a comparative cross-sectional study Ultrasound has practical advantages over MRI for an initial workup: it is cheaper, faster, and lets the examiner see the tendon while you move your ankle in real time. MRI still has a role for complex cases, especially when surgery is being considered or when a systemic inflammatory condition needs full characterization.
X-rays are useful mainly for identifying Haglund’s deformity, posterior heel spurs, or spur fractures. They do not show soft tissue well, so a normal X-ray does not rule out bursitis or tendon degeneration.
Exercise and Loading Programs
For insertional Achilles tendinopathy specifically, exercise-based rehabilitation has the strongest evidence base of any nonsurgical option. A review of treatment options for insertional Achilles tendinopathy concluded that exercise has the highest level of evidence supporting its ability to reduce pain.14PubMed Central. Nonsurgical Treatment Options for Insertional Achilles Tendinopathy The key detail, though, is that the standard Alfredson protocol (eccentric heel drops performed off the edge of a stair) can worsen insertional pain because the deep ankle dorsiflexion at the bottom of the movement compresses the already irritated insertion against the calcaneus.
The workaround is to perform the loading exercises on a flat surface rather than off a step, keeping the heel no lower than the forefoot. Isometric holds, where you simply push up onto your toes and hold the position, are another good starting point because they can reduce pain without the compressive provocation. The progression from isometrics to slow heavy resistance training to eventually plyometric loading follows a pattern that lets the tendon adapt gradually. How long this takes varies, but expect weeks to months of consistent work rather than a quick turnaround. Tendon tissue remodels slowly compared to muscle, and posterior heel conditions are notorious for requiring patience.
Heel Lifts and Footwear Changes
A simple heel lift inserted into your shoe can make a meaningful difference. A study of patients with insertional Achilles tendinopathy found that pain during walking dropped significantly right after a heel lift was fitted, and the improvement held after two weeks of continuous wear.15PubMed Central. Immediate and Short-Term Effects of In-Shoe Heel-Lift Orthoses on Clinical and Biomechanical Outcomes in Patients With Insertional Achilles Tendinopathy The mechanism is straightforward: a lift of about 12 millimeters reduces the tensile load on the Achilles tendon by slightly shortening its working length during the stance phase of walking.16PubMed. The Effect of an In-shoe Orthotic Heel Lift on Loading of the Achilles Tendon During Shod Walking Less pull on the tendon means less compression at the insertion, which means less pain.
Footwear itself matters beyond the lift. If Haglund’s deformity or retrocalcaneal bursitis is part of the picture, shoes with rigid, unyielding heel counters will keep aggravating the bump. Switching to shoes with a soft or absent heel counter, open-backed shoes, or even temporarily using clogs or slides can reduce external pressure on the area. For runners, shoes with a higher heel-to-toe drop accomplish something similar to a heel lift by keeping the ankle in slight plantarflexion throughout the gait cycle. These are not permanent solutions, but they buy time for loading programs and other treatments to take effect.
Shock Wave Therapy
Extracorporeal shock wave therapy (ESWT) delivers focused or radial pressure waves to the affected area and has accumulated a reasonable evidence base for Achilles tendinopathy. A review of trials with strong methodological ratings found that about 64% of patients with chronic insertional Achilles tendinopathy reported being completely recovered or much improved four months after completing a course of radial shock wave therapy. When shock wave therapy was combined with an eccentric loading program, that figure rose to about 82%.17PubMed Central. Extracorporeal Shock Wave Therapy for Achilles Tendinopathy Longer-term data is encouraging as well: a study tracking patients for five years after shock wave therapy found sustained improvements in pain and function scores, with particularly strong results in physically active patients.18PubMed Central. Therapeutic Response of Extracorporeal Shock Wave Therapy for Insertional Achilles Tendinopathy Between Sports-Active and Nonsports-Active Patients With 5-Year Follow-up
The caveats are real, though. Not all trials agree. Some found no benefit of shock wave therapy over control treatments, and ESWT has not convincingly outperformed other options like platelet-rich plasma injections or high-volume image-guided injections in head-to-head comparisons.17PubMed Central. Extracorporeal Shock Wave Therapy for Achilles Tendinopathy In practice, shock wave therapy is most useful as a second-line treatment when a reasonable stretch of rehab exercises and footwear modifications hasn’t been enough. It is generally well tolerated, with temporary redness and mild discomfort during the session as the main downsides.
Corticosteroid Injections and Their Risks
Corticosteroid injections around the heel are sometimes used for retrocalcaneal bursitis when the bursa is the primary pain generator. They can reduce inflammation and provide short-term relief. But they carry a serious risk that is worth understanding before you agree to one. Case reports have documented complete Achilles tendon rupture occurring shortly after corticosteroid injections into the retrocalcaneal bursa.19PubMed Central. Complete Achilles tendon rupture after local infiltration of corticosteroids in the treatment of deep retrocalcaneal bursitis The bursa sits in direct contact with the tendon, so any medication injected into that space inevitably bathes the tendon’s undersurface.
Corticosteroids are known to weaken collagen, and a tendon that is already degenerative from tendinopathy is more vulnerable to rupture. Clinicians writing about this complication note that while local corticosteroid injection may help the symptoms of retrocalcaneal bursitis, it poses a definite risk of Achilles tendon rupture.20PubMed. Can local corticosteroid injection in the retrocalcaneal bursa lead to rupture of the Achilles tendon and the medial head of the gastrocnemius muscle? This does not mean injections should never be used, but it does mean they should be a considered decision rather than a reflexive one. Ultrasound-guided injection can improve accuracy, and limiting the number of injections reduces cumulative exposure. If your doctor suggests an injection, ask whether you have tendon degeneration in addition to bursitis, because that combination raises the stakes.
Why the Achilles Region Is Uniquely Vulnerable
It is worth understanding why this particular spot in the body seems so prone to trouble. The Achilles tendon is the thickest and strongest tendon you have, yet it operates under enormous loads. Every time you walk, the tendon transmits forces several times your body weight. When you run or jump, those forces increase dramatically. The insertion zone is especially stressed because it is where the soft, flexible tendon meets rigid bone, and it has to manage both pulling and compressive forces simultaneously. Research into primate evolution has shown that modern humans have a uniquely long Achilles tendon compared to other primates, an adaptation that boosts efficiency during walking and running but that also means more tendon tissue under load.21PubMed Central. Evidence for an elongated Achilles tendon in Australopithecus
The blood supply at the insertion is another factor. The zone where the tendon attaches to bone receives less blood flow than the mid-tendon, which means it heals more slowly after microinjury and is more susceptible to degenerative changes over time. Add in the tight quarters described earlier, where tendon, bursa, and bone are packed against each other with almost no room for swelling, and you have an anatomical setup practically designed to create chronic problems when anything goes slightly wrong. None of this means posterior heel pain is inevitable, but it does explain why it is so common, so stubborn, and so worth addressing early rather than hoping it resolves on its own.