Carpal tunnel syndrome is the most frequent neuropathy of the upper extremity, that mainly occurs in manual workers and individuals, whose wrist is overloaded by performing repetitive precise tasks. In the past it was common among of typists, seamstresses and mechanics, but nowadays it is often caused by long hours of computer keyboard use. The patient usually complains of pain, hypersensitivity and paresthesia of his hand and fingers in the median nerve distribution. The symptoms often increase at night. In further course of the disease atrophy of thenar muscles is observed. In the past the diagnosis was usually confirmed in nerve conduction studies. Nowadays a magnetic resonance scan or an ultrasound scan can be used to differentiate the cause of the symptoms. The carpal tunnel syndrome is usually caused by compression of the median nerve passing under the flexor retinaculum due to the presence of structures reducing carpal tunnel area, such as an effusion in the flexor tendons sheaths (due to overload or in the course of rheumatoid diseases), bony anomalies, muscle and tendon variants, ganglion cysts or tumors. In some cases diseases of upper extremity vessels including abnormalities of the persistent median artery may also result in carpal tunnel syndrome. We present a case of symptomatic carpal tunnel syndrome caused by thrombosis of the persistent median artery which was diagnosed in ultrasound examination. The ultrasound scan enabled for differential diagnosis and resulted in an immediate referral to clinician, who recommended instant commencement on anticoagulant treatment. The follow‑up observation revealed nearly complete remission of clinical symptoms and partial recanalization of the persistent median artery.

ultrasonography, diagnostic imaging, median nerve, CTS, thrombosis of the persistent median artery