Foot Ultrasound Scan: What an Ultrasound Scan of the Foot Shows, From Plantar Fasciitis to Morton's Neuroma

A foot ultrasound uses sound waves to look at the soft tissues of the foot, such as the thick band of tissue under the heel and arch, the tendons around the ankle and the nerves between the toes. People often search for a foot ultrasound for plantar fasciitis or a Morton's neuroma ultrasound, but the NHS says plantar fasciitis pain can usually be eased by yourself, and many foot problems are diagnosed without an ultrasound scan of the foot at all.

This guide explains what a foot ultrasound can and cannot show, how it compares with MRI and X-ray, what happens during the scan, and how referral works if you are thinking about a private ultrasound scan.

What a foot ultrasound can show

The NHS ultrasound scan page says ultrasound is used to see images of the inside of the body, such as muscles, and to investigate symptoms such as pain or a lump. George Eliot Hospital NHS Trust adds that ultrasound can assess how some parts of the body work at the time of the scan, especially tendons and muscles. In the foot, that makes it useful for:

• The plantar fascia, the band of tissue under the heel and arch that is painful in plantar fasciitis.
• Morton's neuroma, a thickening of tissue around a nerve, usually between the 3rd and 4th toes.
• Tendons, such as the Achilles tendon at the back of the heel and tibialis posterior on the inner side of the ankle.
• Lumps, such as a ganglion cyst on the top of the foot.

The NHS ganglion cyst page says a ganglion is a fluid-filled lump that usually appears on the wrist or hand but can be on the top of the foot, and that most often get better without treatment. It says to see a GP if you are worried about a lump, if it gets bigger, or if it is hard and does not move. For tendon pain at the back of the heel, our guide to Achilles tendon pain: ultrasound or MRI explains when each scan is used.

Foot ultrasound for plantar fasciitis: self-care comes first

The NHS describes plantar fasciitis as pain on the bottom of the foot, around the heel and arch, that is often worst when you first get up after sleeping or resting and eases as you move. It says you can usually ease the pain yourself with rest, raising the foot, an ice pack wrapped in a towel, cushioned shoes with good arch support, gentle stretches and painkillers such as paracetamol or ibuprofen. The NHS plantar fasciitis page does not list a scan as a usual step.

The NHS says to see a GP if your foot pain has not improved after treating it yourself for 2 weeks, if the pain is severe, getting worse or keeps coming back, if you have tingling or loss of feeling in your foot, or if you have diabetes and foot pain. A GP may suggest a physiotherapist or podiatrist, and in many areas you can contact NHS community musculoskeletal services without a GP referral.

When pain does not settle, ultrasound can support the diagnosis. In a study published in the Annals of the Rheumatic Diseases, ultrasound showed the plantar fascia was thicker and less bright (reduced echogenicity) in painful heels than in pain-free heels, and the authors concluded that ultrasound allows confirmation of the clinical diagnosis. The same study used ultrasound to guide injections for plantar fasciitis that had not responded to other treatment.

Morton's neuroma ultrasound: when it is used

The NHS Morton's neuroma page describes shooting, stabbing or burning pain between the 3rd and 4th toes, and a feeling like a pebble is stuck under your foot. It says a GP can look at your foot to see if it is Morton's neuroma and refer you to a foot specialist if needed, and that self-care such as wide, low-heeled shoes and soft insoles often helps.

A Morton's neuroma leaflet from Wrightington, Wigan and Leigh Teaching Hospitals says the diagnosis can be made by your clinician, and that occasionally you may be referred for an ultrasound or MRI scan. It also says a steroid injection may be given in clinic or under ultrasound guidance. So a Morton's neuroma ultrasound is usually a second step, used when the diagnosis is uncertain or treatment is being planned, rather than the first test.

Foot ultrasound vs MRI vs X-ray: what ultrasound cannot show

Ultrasound is not a good test for bone. George Eliot Hospital explains that sound waves do not travel well through air or bone, and that bone can block the path of the waves, creating an 'acoustic shadow' that can hide part of the image. That means fine bone detail, and most fractures, are a job for other tests.

Stress fractures are a common example. A University Hospitals Sussex stress fracture leaflet says they happen when something puts too much stress on a bone, and that not all stress fractures show on an X-ray, because the early changes can be too small to see; a later X-ray may show them. It also says that if a new X-ray or scan would not change how the fracture is managed, you do not need one. A suspected stress fracture is usually looked at with X-ray or MRI rather than ultrasound.

In short: X-ray shows bone and joints, but uses ionising radiation and always needs a referrer; see our foot X-ray page. MRI shows bone and soft tissue together in detail and suits more complex problems; see our foot and ankle MRI scan page. Ultrasound suits the soft tissues listed above. After an injury, our guide on whether a sprained ankle needs an X-ray or MRI explains the usual order of tests.

What happens during a foot ultrasound scan

The NHS says a healthcare professional puts a slippery gel on your skin and moves a small device called a probe across it. Ultrasound scans do not use any radiation, unlike X-rays or CT scans, and the NHS says the sound waves used are safe. You may be asked to remove jewellery from the area, so loose trousers or a skirt that let the sonographer reach your foot and ankle are easiest.

Because ultrasound shows tendons and muscles working in real time, you may be asked to move your toes, foot or ankle during the scan. The probe usually does not hurt, but the NHS notes it can feel uncomfortable over a painful area. The NHS says an ultrasound scan can take around 10 to 45 minutes, but it might take longer.

You may get your results at the end of the appointment, or it may take a few weeks, depending on why you had the scan. A clear result does not always explain your pain or rule out every cause, so talk the report through with the clinician who referred you. Our guide to what ultrasound can detect covers the wider uses of ultrasound.

Referral, and when foot pain needs urgent help

Because ultrasound does not use ionising radiation, some private clinics accept self-referral for a foot ultrasound, depending on the clinic's own policy. Others ask for a referral from a GP, physiotherapist, podiatrist or consultant. Our guide to private ultrasound without a GP referral explains the options. A foot X-ray is different: under the Ionising Radiation (Medical Exposure) Regulations 2017 it always needs a referrer, which many private clinics arrange through their own doctor.

Some foot pain should not wait for a scan. The NHS page on pain in the bottom of the foot says to call 111, or go to an urgent treatment centre, if you have severe pain, cannot walk, your foot has changed shape or is at an odd angle, you heard a snap, grinding or popping noise at the time of injury, or you feel faint, dizzy or sick from the pain.

Key points

• A foot ultrasound is good for soft tissues: the plantar fascia, Morton's neuroma, tendons and lumps such as ganglion cysts.
• It is not a good test for bone, so suspected stress fractures usually need X-ray or MRI.
• Most plantar fasciitis eases with self-care; the NHS says to see a GP if it is not better after 2 weeks.
• Ultrasound may be self-referral at some clinics, depending on clinic policy; an X-ray always needs a referrer.

Comparing clinics on FindScan

You can compare clinics offering a foot ultrasound near you on our private ultrasound scan page, see each clinic's own listed price, and send an enquiry to the clinic you choose. The clinic contacts you to arrange your scan, confirms the final price and tells you whether it needs a referral.

FindScan is a directory of independent, regulated imaging clinics, not a healthcare provider, and nothing here replaces advice from your GP, podiatrist or the clinician treating you. Speak to them about your symptoms or results; if your symptoms are urgent, call NHS 111, or 999 in an emergency.