Heel Pain Explained: Plantar Fasciitis, Achilles Tendinopathy and Other Common Causes
Heel pain is often blamed on plantar fasciitis, but the heel is a complex area made of fascia, tendons, bursae, nerves, fat pad tissue, ligaments and bone. Identifying the correct structure is important because treatment can vary significantly.
Why heel pain should not be ignored
Heel pain is one of the most common foot and ankle problems seen by GPs, podiatrists, physiotherapists, sports medicine clinicians and musculoskeletal ultrasound practitioners. It can affect runners, athletes, people who stand for long periods, office workers and older adults.
For some people, heel pain develops gradually over months. For others, it appears suddenly after an injury, a change in footwear or an increase in walking, running or training. Understanding the likely cause is important because the best treatment depends on the structure involved.
Understanding the anatomy of the heel
The heel is designed to absorb impact and support body weight during standing, walking and running. Pain may arise from several structures, including:
Calcaneus
The heel bone, which forms the foundation of the heel.
Plantar fascia
A strong band of connective tissue running from the heel towards the toes.
Achilles tendon
The large tendon connecting the calf muscles to the back of the heel.
Retrocalcaneal bursa
A small fluid-filled sac behind the heel bone near the Achilles tendon.
Plantar fat pad
The natural cushioning tissue beneath the heel.
Nerves and ligaments
Several nerves and stabilising soft tissues pass around the ankle and heel.
Why does heel pain develop?
The foot experiences large forces during everyday movement. During walking, the heel repeatedly absorbs body weight. During running, forces may be several times higher. Over time, repeated loading can cause microtrauma, degeneration, tendon injury, fascial injury or irritation of nearby soft tissues.
Risk factors may include age, body weight, footwear, biomechanics, foot posture, tight calf muscles, prolonged standing, running and sudden changes in activity level.
Plantar fasciitis: the most common cause of heel pain
Plantar fasciitis is responsible for a large proportion of heel pain cases. The plantar fascia supports the arch of the foot, helps distribute forces during walking and stores and releases energy during movement.
The term “plantar fasciitis” suggests inflammation, but many long-standing cases are better described as plantar fasciopathy. This is because the tissue may show thickening, collagen disorganisation, degeneration and a poor healing response rather than simple inflammation alone.
Typical symptoms of plantar fasciitis
- First-step pain: pain is often worst during the first few steps in the morning.
- Pain under the heel: commonly felt at the inner or underside aspect of the heel.
- Pain after rest: symptoms may return after sitting or resting.
- Pain after activity: discomfort may increase after walking, running or exercise.
What can ultrasound show in plantar fasciitis?
Ultrasound may demonstrate plantar fascia thickening, reduced echogenicity, loss of the normal fibre pattern, increased blood flow in some cases and partial tears in more severe disease. A plantar fascia thickness above approximately 4 mm may support the diagnosis when interpreted with symptoms and clinical assessment.
What is a heel spur?
A heel spur is a bony projection extending from the calcaneus. Many people assume the spur itself is the cause of heel pain, but many heel spurs are not painful. In many cases, a spur is a sign of long-standing traction forces rather than the main source of symptoms.
Ultrasound helps assess the soft tissues around the spur, including the plantar fascia and adjacent tissues, rather than focusing on the bony spur alone.
Plantar fascia tears
Less commonly, the plantar fascia may partially or completely tear. This can occur after long-standing plantar fasciitis, sudden overload, sporting injury or, in some cases, following steroid injection.
Symptoms may include sudden sharp pain, an audible pop, bruising and difficulty walking. Ultrasound can help identify partial tears, full-thickness tears and associated haematoma.
Achilles tendinopathy and Achilles tendon tears
The Achilles tendon is the strongest tendon in the body, but it is still vulnerable to overload and injury. Achilles tendinopathy is usually a gradual degenerative process in which collagen fibres become disrupted, the tendon thickens and the tendon becomes less efficient at handling load.
| Type | Where it occurs | Common features |
|---|---|---|
| Mid-portion Achilles tendinopathy | Usually 2–6 cm above the tendon insertion | Back-of-heel or lower calf pain, morning stiffness, pain during or after running, swelling or tenderness. |
| Insertional Achilles tendinopathy | Where the tendon attaches to the calcaneus | Posterior heel pain, possible calcification, bone spur association and footwear-related irritation. |
| Achilles tendon tear or rupture | Partial or complete disruption of the tendon | Sudden pain, snapping sensation, difficulty walking or inability to push off. Urgent assessment is required if rupture is suspected. |
Ultrasound can assess Achilles tendon thickening, hypoechoic degeneration, neovascularisation, calcification, bursitis, partial tears and complete rupture.
Other common causes of heel pain
Retrocalcaneal bursitis
The retrocalcaneal bursa lies between the Achilles tendon and the heel bone. It may become inflamed due to friction, tight footwear or associated Achilles tendon disease. Symptoms often include swelling, tenderness and posterior heel pain.
Haglund’s syndrome
A Haglund deformity is a bony prominence at the back of the heel. It may contribute to Achilles irritation, bursitis and discomfort from footwear. Ultrasound can identify associated soft tissue abnormalities.
Baxter’s nerve entrapment
Compression of Baxter’s nerve can cause heel pain that may closely mimic plantar fasciitis. Symptoms can include burning pain, tingling and persistent discomfort despite treatment.
Tarsal tunnel syndrome
The tibial nerve passes through a tunnel near the ankle. Compression may cause heel pain, burning sensations, numbness or tingling. Ultrasound may help identify nerve enlargement, ganglion cysts or soft tissue compression.
Fat pad syndrome
The heel fat pad acts as a natural shock absorber. Over time, it may thin, degenerate or lose cushioning ability. Symptoms may include central heel pain and pain when standing on hard surfaces.
Calcaneal stress fracture
Repeated loading can sometimes cause a stress fracture of the heel bone, particularly in runners, military personnel and athletes. MRI is often preferred for suspected bone stress injury, although ultrasound may show indirect soft tissue signs in selected cases.
When should you consider an ultrasound scan?
A foot and ankle ultrasound scan may be useful if heel pain persists, symptoms are worsening, a tendon tear is suspected, conservative treatment has failed, or an ultrasound-guided injection is being considered.
| Reason for scan | What ultrasound may assess |
|---|---|
| Plantar heel pain | Plantar fascia thickening, tears, fibre pattern and local soft tissues. |
| Back-of-heel pain | Achilles tendon, insertional changes, retrocalcaneal bursa and adjacent soft tissues. |
| Burning or tingling pain | Nerves, soft tissue masses, ganglion cysts or compression-related features. |
| Swelling or a lump | Bursitis, cysts, fluid collections, soft tissue lesions or inflammatory changes. |
| Suspected tendon tear | Partial tear, full-thickness tear, haematoma and dynamic tendon movement. |
Treatment options for heel pain
Treatment depends on the diagnosis. Options may include physiotherapy, activity modification, calf and plantar fascia stretching, footwear modification, orthotics, shockwave therapy in selected cases, ultrasound-guided injections in selected conditions and, rarely, surgery.
Because different conditions can produce similar symptoms, diagnosis is important before deciding on a treatment plan.
When should you seek medical advice?
You should seek medical assessment if heel pain persists beyond several weeks, pain is worsening, swelling develops, walking becomes difficult, symptoms follow a sudden injury, or you suspect an Achilles tendon rupture.
Frequently asked questions
Is plantar fasciitis always inflammation?
Not always. Many long-standing cases involve degenerative changes and thickening of the plantar fascia rather than simple inflammation alone. This is why some clinicians use the term plantar fasciopathy.
Can a heel spur cause pain?
A heel spur can be present in people with heel pain, but many heel spurs are not painful. The surrounding soft tissues often explain the symptoms better than the spur itself.
Can ultrasound diagnose Achilles tendon rupture?
Ultrasound is commonly used to assess suspected Achilles tendon tears and ruptures. If rupture is suspected, prompt clinical assessment is important.
Do I need a GP referral?
London Private Ultrasound offers private musculoskeletal ultrasound appointments, and many patients can self-refer. If you are unsure which scan is most suitable, our team can guide you.
Final thoughts
Heel pain is common, but it has many possible causes. While plantar fasciitis is the most frequent diagnosis, conditions affecting the Achilles tendon, bursae, nerves, fat pad and surrounding structures can produce similar symptoms.
Musculoskeletal ultrasound is an excellent diagnostic tool for many soft tissue causes of heel pain and can help guide effective treatment and recovery planning.
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References and clinical review
References used in preparation: NHS foot and heel pain guidance; NICE Clinical Knowledge Summary for plantar fasciitis; British Orthopaedic Foot & Ankle Society information; BMUS musculoskeletal ultrasound guidance; American Academy of Orthopaedic Surgeons information on plantar fasciitis and Achilles tendinitis; British Journal of Sports Medicine research on Achilles tendinopathy.
Article preparation and clinical review: This patient information page was prepared with AI-assisted editorial support and reviewed for clinical accuracy by Dr Pedram Aghaei — Vascular Scientist, SVT reg. SVT 679 · Registered Clinical Technologist, RCT reg. 93290 · BMUS 20702, and Dr Hosna Rashidi — BMUS 29386, SVT reg. M11114.
Disclaimer: This article is intended for general patient information only and does not replace a medical consultation.