Median nerve deformation and displacement in the carpal tunnel during index finger and thumb motion

Margriet H.M. Van Doesburg, Yuichi Yoshii, Hector R. Villarraga, Jacqueline Henderson, Stephen S. Cha, Kai Nan An, Peter C. Amadio

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


The purpose of this study was to investigate the deformation and displacement of the normal median nerve in the carpal tunnel during index finger and thumb motion, using ultrasound. Thirty wrists from 15 asymptomatic volunteers were evaluated. Cross-sectional images during motion from full extension to flexion of the index finger and thumb were recorded. On the initial and final frames, the median nerve, flexor pollicis longus (FPL), and index finger flexor digitorum superficialis (FDS) tendons were outlined. Coordinate data were recorded and median nerve cross-sectional area, perimeter, aspect ratio of the minimal-enclosing rectangle, and circularity in extension and flexion positions were calculated. During index finger flexion, the tendon moves volarly while the nerve moves radially. With thumb flexion, the tendon moves volarly, but the median nerve moves toward the ulnar side. In both motions, the area and perimeter of the median nerve in flexion were smaller than in extension. Thus, during index finger or thumb flexion, the median nerve in a healthy human subject shifts away from the index finger FDS and FPL tendons while being compressed between the tendons and the flexor retinaculumin the carpal tunnel. We are planning to compare these data with measurements in patients with carpal tunnel syndrome (CTS) and believe that these parameters may be useful tools for the assessment of CTS and carpal tunnel mechanics with ultrasound in the future.

Original languageEnglish (US)
Pages (from-to)1387-1390
Number of pages4
JournalJournal of Orthopaedic Research
Issue number10
StatePublished - Oct 2010


  • Carpal tunnel
  • Deformation
  • Median nerve
  • Motion
  • Ultrasound

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


Dive into the research topics of 'Median nerve deformation and displacement in the carpal tunnel during index finger and thumb motion'. Together they form a unique fingerprint.

Cite this