Kerala Journal of
Physical Medicine and Rehabilitation
Official Journal of the Kerala Chapter of Indian Association of Physical Medicine and Rehabilitation
Volume 25 | Issue 2 | June 2026
Original Article
Ultrasonographic Measurement of Median Nerve Cross-Sectional Area for the Diagnosis and Severity Assessment of Carpal Tunnel Syndrome: A Cross-Sectional Diagnostic Study
Arya Vijayan
Dept of Physical Medicine & Rehabilitation, Govt T D Medical College, Alappuzha,
Dr Arya Vijayan MD PMR
Kaniyamparambu House, Thanneer-mukkom P O Cherthala, Alappuzha – 688527
Email : vijayanarya555@gmail.com
Arya Vijayan. Ultrasonographic Measurement of Median Nerve Cross-Sectional Area for the Diagnosis and Severity Assessment of Carpal Tunnel Syndrome: A Cross-Sectional Diagnostic Study. KJPMR. 2026;25(2):10-14.
Background: Carpal tunnel syndrome (CTS) is the most common form of peripheral nerve entrapment. Nerve conduction studies (NCS) are considered the gold standard for diagnosis; however, ultrasonography (US) has emerged as a non-invasive alternative.
Objectives: To evaluate the efficacy of ultrasonographic measurement of median nerve cross-sectional area (CSA) in diagnosing and grading the severity of CTS and to assess its association with comorbidities such as diabetes mellitus.
Methods: This cross-sectional diagnostic study was conducted in the Department of Physical Medicine and Rehabilitation at a tertiary care center. A total of 67 wrists from 37 patients were included. All participants underwent clinical examination along with assessment using Boston Carpal Tunnel Questionnaire (BCTQ). NCS were followed by ultrasonographic measurement of median nerve CSA at the carpal tunnel inlet. Severity was graded using Modified Bland’s scale and receiver operating characteristic (ROC) analysis was used to determine optimal cut-off values.
Results: Mean CSA increased significantly with CTS severity. The optimal CSA cut-off for diagnosing CTS was 9.5 mm² with sensitivity 95.1% and specificity 96.2% (AUC = 0.959). Cut-offs of 10.5 mm² and 14.5 mm² effectively differentiated mild-to-moderate and moderate-to-severe CTS respectively. Clinical tests showed no significant association with NCS severity. No statistically significant association was found between CTS and comorbidities.
Conclusion: Ultrasonographic measurement of median nerve CSA demonstrates excellent diagnostic accuracy and effectively grades CTS severity. It can serve as a reliable, non-invasive alternative or adjunct to NCS in appropriate clinical settings.
Keywords: Carpal tunnel syndrome, Ultrasound, Cross-sectional area, Diagnostic accuracy