Ultrasonography of Peripheral Nerve Abnormalities

Nerve swelling accompanied by a hypoechoic structure is a common occurrence in peripheral nerve entrapment syndrome and is also indicative of a sort of tumour-like hyperplasia after nerve injury. Nerve entrapment often occurs at the bone fibre canals or tunnels, such as the median nerve in the carpal canal, the ulnar nerve in the cubital tunnel, the common peroneal nerve in the fibular canal at the fibular head and the tibial nerve in the tarsal tunnel. The nerve generally presents a narrow radial line at the entrapment where the proximal and/or distal end is swollen, which is seen along with hypoechoic changes and the absence of a mesh or layer structure.