Diagnostic ultrasound for tendon problems: what can the examination show?

In an ultrasound examination of muscles and bones, sound waves are sent into the tissue and create images in real time [7]. The guideline for Achilles tendon pain describes ultrasound as inexpensive, low-risk and easily accessible compared with MRI [1].

Lægehåndbogen describes that ultrasound gives a dynamic assessment of the tendon, but that the examination requires expertise [3]. Sound waves do not penetrate bone, and deep structures in the joints are therefore often better assessed with MRI or X-ray [7].

In Achilles tendon pain, ultrasound can show the degree of thickening in the tendon and any micro-ruptures [3]. A review article on the shoulder tendon supraspinatus describes that the method can show thickening, thinning and tears, and thereby distinguish between tendinopathy, partial tears and complete ruptures [6].

In plantar fasciitis, a thickened plantar fascia, more than four millimetres, with a darker tissue appearance is regarded as a typical ultrasound finding [2]. NHI writes that ultrasound or MRI can in some cases confirm the diagnosis [4].

The guideline for Achilles tendon pain emphasises that increased tendon thickness is common in tendinopathy, but not specific. Up to a quarter of adults without symptoms also have increased thickness. Normal values vary with age, height, body mass index and sex [1]. The guideline does not establish a direct link between imaging findings and how severe the symptoms are [1].

Imaging findings must therefore be read together with the history and clinical examination [1]. A review article on shoulder ultrasound concludes that the method is reliable when carried out by skilled examiners [6].

In Achilles tendon pain, the diagnosis is usually made from the history and examination, and the guideline states that imaging is not necessary to make it. It is suggested when the diagnosis is uncertain, when improvement fails to appear or the symptoms worsen during treatment, or when a procedure is considered [1]. NHI writes that ultrasound is used only in exceptional cases in Achilles tendon pain [5].

For heel pain, the guideline recommends that imaging is usually not used before other treatment has been tried, when the clinical criteria are met. X-ray is the first choice, and when plantar fasciitis or a fascia rupture is suspected, MRI or ultrasound is the next step [2].

As the symptoms are followed up, ultrasound can be used to compare the tendon with the healthy side and to re-examine during the course [7]. Because imaging findings and symptoms do not always correspond [1], a new examination is read together with how pain and function have developed. The exercise itself is built on gradually increasing loading, and you can read more about it in the article on rehabilitation of tendon problems.

According to Dr.Dropin, the ultrasound examination is always combined with a conversation and a clinical examination, and you do not need a referral from a doctor to book an appointment [7]. Ultrasound is one of several aids, and the therapist assesses together with you whether the examination is necessary in your case.

If you have tendon problems that are not improving, or the diagnosis is uncertain, a physiotherapist can examine you and assess whether ultrasound can give useful additional information. You can read more about diagnostic ultrasound and about physiotherapy.

What can ultrasound show in a tendon injury?

Ultrasound can show thickening of a tendon and micro-ruptures [3], and in the shoulder tendon, among other things, thinning and tears [6]. The findings are read together with the symptoms [1].

Do I need ultrasound to get the diagnosis?

Not necessarily. The guideline for Achilles tendon pain states that imaging is not necessary to make the diagnosis, but that it may be relevant when the diagnosis is uncertain or improvement fails to appear [1].

Is ultrasound better than MRI?

They have different uses. Ultrasound is inexpensive and easily accessible, while MRI is often used when deep structures are to be assessed, since sound waves do not penetrate bone [1][7].

Can a thickened tendon be found without pain?

Yes. According to the guideline for Achilles tendon pain, up to a quarter of adults without symptoms also have increased tendon thickness [1].

The article on rehabilitation of tendon problems describes gradual loading and exercise. You can find more articles in the overview of articles.

This article was written by Dr.Dropin Fysikalske and is based on the sources listed below. It gives general information and does not replace an examination by a healthcare professional.

The websites were accessed and read on 22 October 2026.

1. Chimenti RL, Neville C, Houck J, Cuddeford T, Carreira D, Martin RL. Achilles pain, stiffness, and muscle power deficits: midportion Achilles tendinopathy revision, 2024. J Orthop Sports Phys Ther. 2024;54(12). Link

2. Koc TA Jr, et al. Heel pain, plantar fasciitis: revision 2023. J Orthop Sports Phys Ther. 2023. Link

3. Lind M. Akillestendinose. Lægehåndbogen, sundhed.dk. Revised 9 October 2026. Link

4. Plantar fasciitt (hælsmerter) (plantar fasciitis, heel pain). NHI.no. Last updated 22 September 2025. Link

5. Akillessenebetennelse (Achilles tendonitis). NHI.no. Last updated 15 October 2024. Link

6. Manske RC, Voight M, Page P, Wolfe C. The application of musculoskeletal ultrasound in the diagnosis of supraspinatus injuries. Int J Sports Phys Ther. 2023;18(5). doi:10.26603/001c.88377. Only the abstract was accessed and read. Link

7. Diagnostisk ultralydundersøkelse (diagnostic ultrasound examination). Dr.Dropin Fysikalske. Link