Related Experiment Video
Updated: May 28, 2026

Screening of Axonal Degeneration in Carpal Tunnel Syndrome Using Ultrasonography and Nerve Conduction Studies
Published on: January 11, 2019
Ulnar nerve conduction abnormalities in carpal tunnel syndrome
Oya Umit Yemisci1, Seniz Akcay Yalbuzdag, S Nur Saracgil Cosar
1Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Baskent University, M. Fevzi Cakmak Cadde 5, Sok. No. 48, Bahcelievler, Ankara, Turkey. oyaumit@hotmail.com
Introduction:
The aim of this study was to verify the involvement of ulnar nerve fibers in cases of carpal tunnel syndrome (CTS) and investigate the correlation between ulnar nerve conduction parameters and extra-median spread of symptoms.
Methods:
Electrophysiological studies were conducted in 93 CTS and 76 control hands. Patients were analyzed with regard to symptoms in the fifth finger.
Results:
In the CTS cases, ulnar distal motor latency (DML) and distal sensory latency (DSL) were significantly longer, and amplitudes were lower than in controls. Increased median nerve DML correlated with increased ulnar nerve DSL and decreased sensory amplitudes and conduction velocities (SCVs). In cases with symptoms in the fifth finger, ulnar nerve SCVs and amplitudes were lower than in patients without symptoms.
Conclusions:
Pathological processes leading to median neuropathy in CTS may affect ulnar nerve motor and sensory fibers in the Guyon canal. This may explain the extra-median spread of sensory symptoms in CTS patients.
Related Concept Videos
Spinal Nerves: Plexus I
The Cervical Plexus
The cervical plexus, formed by the anterior rami of the first four...
Bones of the Upper Limb: Ulna
Arteries of the Upper Limbs
Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation
Diabetic Neuropathy
Disorders of the Autonomic Nervous System
Raynaud's disease, also known as Raynaud's phenomenon, is a...