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Ultrasound imaging of small peripheral nerves – a primer for radiologists Cover

Ultrasound imaging of small peripheral nerves – a primer for radiologists

Journal of Ultrasonography
Volume 26 (2026): Issue 104 (April 2026)
By: Aakanksha Agarwal,  Abhishek Chandra,  Palak Dhakar and  Mahesh Prakash  
Open Access
|Mar 2026
Figures & tables

Figures & Tables

Fig. 1.

Schematic diagram illustrating the honeycomb architecture of nerves when imaged in cross-section (yellow – epineurium; purple – perineurium; orange – endoneurium). The image on the right shows the normal honeycomb architecture of the median nerve (asterisk) with an echogenic epineurium

Fig. 2.

Longitudinal image of the median nerve (yellow) and the underlying flexor tendon (green) within the carpal tunnel. The distal radius (R) and scaphoid (S) can be seen at inlet. Note the tubular appearance of the nerve, contrasting with the linear fascicular appearance of the underlying tendon

Fig. 3.

The medial antebrachial cutaneous nerve (yellow arrow) can be identified adjacent to the basilic vein (blue) within the subcutaneous fat, superficial to the muscular fascia. The probe position is shown in the inset image. Care should be taken to ensure minimal probe pressure to identify the basilic vein

Fig. 4.

The lateral antebrachial cutaneous nerve (yellow circle) is identified in the antecubital fossa, adjacent to the cephalic vein (A and B). Note probe position in the inset. Image C demonstrates thickening of the LABC (blue arrow) in a patient following biceps tendon repair, compared to the contralateral normal nerve in image D. The orange arrow demonstrates focal scarring of the overlying skin in image C, indicating prior surgical intervention

Fig. 5.

Images A and B demonstrate the normal superficial branch of the radial nerve (yellow) in the distal forearm as it travels in the subcutaneous plane, curving over the distal radius (R) and lying superficial and lateral to the distal brachioradialis muscle (red). Images C and D demonstrate a hypoechoic mass lesion (M) closely abutting the SBRN (yellow arrow) and the posterior interosseous nerve (green arrow) just distal to their origin from the radial nerve in the proximal forearm. Image E demonstrates focal thickening of the SBRN (yellow arrow) at the level of the wrist, superficial to the firstt extensor compartment tendons (red arrow), which show mild effusion consistent with DeQuervain’s tenosynovitis

Fig. 6.

Images A and B demonstrate the normal dorsal cutaneous branch of the ulnar nerve (smaller yellow circle) arising from the ulnar nerve (yellow circle) in the distal forearm (inset). The ulnar nerve lies deep to the flexor carpi ulnaris tendon (red) and gives rise to the DCBUN, which wraps over the ulna and travels in the subcutaneous plane of the dorsal forearm. Image C demonstrates neuroma formation within the DCBUN (asterisk) in a patient with a glass-cut injury in the distal forearm. Image D shows a hypoechoic mass along the DCBUN (asterisk) in the distal dorsal forearm in orthogonal planes, consistent with a peripheral nerve sheath tumor, presenting as a hypoechoic fusiform lesion with the DCBUN seen as a tail at both ends

Fig. 7.

Images A and B demonstrate one of the variant anatomical courses of the palmar cutaneous branch of the median nerve (PCBmn) (small yellow circle). Here, the nerve can be seen ulnar to the flexor carpi radialis (green circle) and superficial to the flexor retinaculum (blue) at the level of the carpal tunnel. In this patient, the nerve courses in the subcutaneous plane more distally than usual. Note the probe position in the inset. The median nerve (yellow circle), flexor tendons (blue), and an incidental low-lying muscle belly of flexor tendons (red) can also be seen. Image C shows an end-neuroma (asterisk) in the PCBmn in a patient with a penetrating injury in the distal forearm. The flexor carpi radialis (R) lies superficial to the nerve, and overlying hypoechoic scar (S) is also present. Image D demonstrates focal thickening of the PCBmn (white asterisk) as it courses medial to the flexor carpi radialis tendon in a patient with thenar pain. This can be compared with the contralateral normal side (yellow asterisk). The median nerve was normal in course and caliber in this patient

Fig. 8.

Images A and B demonstrate the common digital nerve (yellow circle) at the level of the metacarpal head, with the lumbrical muscle (blue) between the flexor tendons (green). The red circle marks the digital vessels. Images C and D show the ulnar and radial branches of the digital nerve (yellow circle) as they course along adjacent fingers. The flexor tendons of the respective fingers can also be seen (green). Image E demonstrates a neuroma in two orthogonal planes in continuity with a common digital nerve (asterisk). Image F shows entrapment of the ulnar digital nerve (red asterisk) of the thumb within scar tissue (S) in a patient following pulley release

Fig. 9.

Images A and B demonstrate the lateral femoral cutaneous nerve (yellow circle) superficial to the muscular fascia (green), lying between the sartorius (S) anteriorly and the tensor fascia lata (TFL) posteriorly. Image C shows thickening of the LFCN as it crosses the inguinal ligament (encircled). The normal proximal caliber of the LFCN can be seen at the level of the iliacus muscle (ILM). Image D demonstrates ultrasound-guided perineural hydrodissection of the LFCN as it courses superficial to the muscular fascia between the TFL and sartorius

Fig. 10.

Images A and B demonstrate the normal medial femoral cutaneous nerve superficial to the femoral vascular bundle, distal to the femoral canal. The nerve originates from the femoral nerve and travels medially, piercing the muscular fascia (green) over the sartorius (S) to innervate the medial thigh. Image C shows a perineural steroid injection around the medial femoral cutaneous nerve within the subcutaneous plane, superficial to the sartorius, in a diabetic patient with persistent pain along the distribution of this nerve

Fig. 11.

Images A and B demonstrate the normal saphenous nerve (yellow) within the adductor canal, deep to the sartorius (S) and the vastoadductor membrane between the vastus medialis (VM) and adductor magnus (A). Images C and D show the saphenous nerve (yellow) after piercing the vastoadductor membrane and giving rise to the infrapatellar branch (green). Note its proximity to the great saphenous vein (blue). Images E and F demonstrate the saphenous nerve (yellow) in the lower medial thigh before piercing the medial muscular septum. In images G and H, the nerve (yellow) lies in the subcutaneous plane in close relation to the great saphenous vein (blue)

Fig. 12.

Images A and B demonstrate the origin of the sural nerve (yellow) in the lateral aspect of the popliteal fossa from the common peroneal nerve (CPN). Here, the CPN is thickened, while the sural nerve remains normal in caliber and echogenicity. Images C and D demonstrate the sural nerve (yellow) at the level of the lateral ankle within the subcutaneous plane between the Achilles tendon (AT) and the peroneal tendons (PL/PB). Image E demonstrates edema within the sural nerve (yellow arrow) in the distal leg, and image F demonstrates a partial neuroma in the sural nerve (yellow arrow) at the level of the ankle following arthroscopy. The red arrow demonstrates the portal site and route, coursing along the lateral margin of the nerve, resulting in partial epineurial disruption

Fig. 13.

Images A and B demonstrate the normal superficial peroneal nerve (yellow) in the mid-lower leg as it pierces the lateral muscular septum, with underlying lateral muscle bellies (M). Image C shows a peripheral nerve sheath tumor involving the superficial peroneal nerve (arrows)

Fig. 14.

Images A and B show an intermetatarsal neuroma (yellow) imaged from the plantar aspect with the probe placed transversely at the level of the metatarsal heads. The metatarsal heads (B) and the intermetatarsal ligament (red) can be seen. Finger pressure from the dorsal aspect accentuates the appearance of the neuroma by displacing it superficially. Image C shows the neuroma (between arrows) in the longitudinal plane
DOI: https://doi.org/10.15557/jou.2026.0005 | Journal eISSN: 2451-070X | Journal ISSN: 2084-8404
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Language: English
Submitted on: Oct 13, 2025
Accepted on: Feb 9, 2026
Published on: Mar 20, 2026
Published by: MEDICAL COMMUNICATIONS Sp. z o.o.
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
ultrasound,
small nerve imaging,
high-frequency imaging
Related subjects:
Medicine,
Basic medical science,
Basic medical science, other

© 2026 Aakanksha Agarwal, Abhishek Chandra, Palak Dhakar, Mahesh Prakash, published by MEDICAL COMMUNICATIONS Sp. z o.o.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 26 (2026): Issue 104 (April 2026)
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