Ultrasound-Based Evaluation of Median Nerve and Flexor Pollicis Longus Tendon in Adolescents: Impact of Smartphone Overuse

Objective: Adolescents are increasingly engaged in prolonged smartphone use, raising concerns regarding potential musculoskeletal effects, particularly on structures involved in repetitive thumb and wrist movements. The aim of this study was to evaluate the impact of smartphone overuse on the cross-sectional area (CSA) of the median nerve (MN) and flexor pollicis longus (FPL) tendon using ultrasonography in adolescents.

Methods: A total of 82 adolescents aged 10-18 years were divided into 2 groups based on the Smartphone Addiction Scale (SAS): high users (≥80) and low users (<80). Bilateral ultrasonographic measurements of the MN and FPL tendon CSAs were taken at predefined anatomical levels. Comparative and correlational analyses were performed using appropriate statistical methods.

Results: Both groups exhibited significantly higher CSA values on the dominant side compared to the nondominant side (P < .05). In the high smartphone use group, the CSA of the MN at the carpal tunnel and FPL tendon was significantly greater than that of the low-use group (P < .05). Positive correlations were found between smartphone use scores and CSA measurements.

Conclusion: Excessive smartphone use in adolescents is associated with increased CSA values of both the MN and FPL tendon, particularly on the dominant side. These findings may reflect early, subclinical structural adaptations that could precede overuse-related symptoms. Ultrasonographic evaluation may serve as a useful tool for early identification and preventive strategies in at-risk youth populations.

Cite this article as: Esmerer E, Özçetin M, Ertürk S, Akkuş E, Us MC. Ultrasound-based evaluation of median nerve and flexor pollicislongus tendon in adolescents: impact of smartphone overuse. Cerrahpaşa Med J. 2026, 50, 0081, doi: 10.5152/cjm.2026.25081.