Ultrasound of peripheral nerves: when can it be relevant?

Peripheral nerves are the nerves outside the brain and spinal cord. With high-resolution ultrasound it is possible to see individual bundles in a nerve and how size and shape change in disease [1]. The advantages highlighted are that the examination gives images in real time and is less invasive than traditional electrophysiological examinations [1].

The editors of an overview in Frontiers in Neurology consider that ultrasound should be the first choice for entrapped nerves. This is their opinion, and it is not based on a direct comparison of the methods [1].

NHI describes ultrasound of nerves as a useful supplement to electrophysiological examinations, especially in chronic inflammatory neuropathies. The author recommends ultrasound as an addition and not as a replacement [2]. In the study the article is based on, ultrasound found more cases than nerve conduction studies, but also gave more false positive findings [2].

The review is from 2020 and is marked as more than two years old on NHI.no. It does not discuss carpal tunnel syndrome or sciatica [2]. Findings on ultrasound must be interpreted together with symptoms and the clinical examination.

NHI describes sciatica from a disc herniation as a weakened intervertebral disc in the lower back pressing on or irritating a nerve root, often the sciatic nerve. The pain radiates from the back down into the leg. The diagnosis is made largely from the history and examination, including the straight leg raise test and a neurological examination of sensation, strength and reflexes [3].

Imaging is usually not needed early in the course. It is used for persistent pain, when another disease is suspected and often before a possible operation, and MRI is preferred over CT [3]. Sound waves do not pass through bone, so a disc herniation in the spine is usually assessed with MRI, as also stated on the page about diagnostic ultrasound.

Our sources do not say how often ultrasound of the sciatic nerve changes the assessment or treatment, so nothing can be said about that here.

Carpal tunnel syndrome is an example of a nerve problem in the arm. The symptoms are tingling, numbness or reduced sensation, sometimes with pain, in the area supplied by the median nerve, especially the middle and index fingers. The symptoms are often worst at night [4]. NHI states that the diagnosis is usually made from the history and examination, and that a nerve conduction study can be used to confirm it. Ultrasound is not described in the NHI article [4].

Frontiers in Neurology describes a study in which the cross-sectional area of the median nerve was measured in carpal tunnel syndrome, and the ultrasound diagnoses agreed well with electrophysiological findings in an Indonesian group of patients. One case report shows how ultrasound revealed calcified nodules pressing on the nerve and prevented an unnecessary operation in one patient. The overview also describes methods for scanning the ulnar and radial nerves [1].

Diagnostic ultrasound uses sound waves to create images of the body's tissues in real time. According to the page about diagnostic ultrasound, the examination is always combined with a conversation and a clinical examination, and the therapist can compare with the healthy side.

Loss of control over urination or bowel movements with sciatica can be caused by compression of the nerves to the bladder and bowel (cauda equina syndrome). NHI then recommends seeking emergency help immediately, for example at an emergency clinic or emergency department [3]. Rapidly increasing paralysis and pain that cannot be managed also call for prompt assessment [3].

In carpal tunnel syndrome, NHI recommends early surgery if the weakness is significant [4]. Weakened strength in the thumb should therefore be assessed by a doctor.

A chiropractor can take your history, examine you clinically and assess whether imaging is relevant, and can refer to MRI, CT or a specialist when needed. Diagnostic ultrasound is used as part of the examination together with a conversation and clinical examination. If you have pain radiating down the leg, you can read more about disc herniation and low back pain.

Can ultrasound show sciatica?

Sciatica from a disc herniation is caused by a disc in the back pressing on a nerve root [3]. Sound waves do not pass through bone, and when imaging is needed, MRI is preferred [3]. Our sources do not discuss ultrasound of the sciatic nerve.

Can ultrasound replace a nerve conduction study?

NHI describes ultrasound as an addition to electrophysiological examinations and not as a replacement [2].

How is carpal tunnel syndrome diagnosed?

Usually from the history and an examination of the hand and arm. When needed, the diagnosis can be confirmed with a nerve conduction study [4].

Do I need a referral to book an appointment?

No. You do not need a referral from a doctor to book an appointment with a chiropractor at Dr.Dropin.

You can find more articles in the overview of articles. The page about chiropractors describes the examination at our clinics.

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. Chang KV, Kim SB. Editorial: Use of ultrasound in diagnosis and treatment of peripheral nerve entrapment syndrome. Front Neurol. 2020;10:1348. doi:10.3389/fneur.2019.01348. Link

2. Johannessen T. Ultralyd ved perifere nevropatier (Ultrasound in peripheral neuropathies). NHI.no. 11 May 2020 (the page is marked as more than two years old). Link

3. Isjias (prolaps) (Sciatica, disc herniation). NHI.no. Last updated 15 January 2026. Link

4. Karpaltunnelsyndrom, diagnostikk (Carpal tunnel syndrome, diagnosis). NHI.no. Last updated 29 September 2025. Link