Orthodromic sensory conduction along the ring finger in normal subjects and in patients with a carpal tunnel syndrome

• Published in: Electroencephalography and clinical neurophysiology Vol. 81; no. 1; pp. 18 - 23
• Main Authors: Lauritzen, Martin, Liguori, Rocco, Trojaborg, Werner
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.02.1991
• Subjects: Adult; Aged; Carpal tunnel syndrome; Carpal Tunnel Syndrome - physiopathology; Conduction velocity; Electromyography; Female; Fingers - innervation; Forearm; Hand; Humans; Male; Median nerve; Median Nerve - physiopathology; Middle Aged; Muscles - physiopathology; Neural Conduction; Reaction Time; Reference Values; Sensation - physiology; Sensory conduction; Ulnar nerve; Ulnar Nerve - physiopathology; Wrist; Carpal tunnel syndrome; Ulnar nerve; Conduction velocity; Sensory conduction; Median nerve
• ISSN: 0168-5597; 0013-4694
• DOI: 10.1016/0168-5597(91)90099-J

The purpose of the present study was to examine the value of measuring sensory conduction along the median and ulnar nerves of the fourth finger in the diagnosis of a carpal tunnel syndrome (CTS). In 23 controls, sensory conductions along median and ulnar nerves were identical. In 28 of 38 patients with CTS, stimulation of the ring finger revealed a reduced conduction velocity along sensory median nerve fibres in contrast to normal conduction along ulnar sensory nerve fibers. In 5 patients, a sensory action potential was absent over the median nerve and in another 5 sensory conduction was normal along both nerves. We conclude that testing of sensory conduction along the ring finger is useful in about 74% of patients with CTS, while in the remaining 26% other fingers must be examined to establish the diagnosis.