Investigations

The diagnosis of CTS is usually a clinical one. Investigations can help if the diagnosis is unclear:

• Ultrasound. Some studies show that patients with CTS have an increased cross-section area of the median nerve within the canal compared with controls
• Electromyographic and nerve conduction studies. These are most helpful for determining the site, and severity, of nerve compression. They have a sensitivity of approximately 85% and a specificity >95%

Learning bite

It is possible to have normal nerve conduction studies with CTS.