Demonstration of extended field-of-view ultrasound's potential to increase the pool of muscles for which in vivo fascicle length is measurable

Amy N. Adkins, Patrick W. Franks, Wendy M. Murray*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Static, B-mode ultrasound is the most common method of measuring fascicle length in vivo. However, most forearm muscles have fascicles that are longer than the field-of-view of traditional ultrasound (T-US). As such, little work has been done to quantify in vivo forearm muscle architecture. The extended field-of-view ultrasound (EFOV-US) method, which fits together a sequence of B-mode images taken from a continuous ultrasound scan, facilitates direct measurements of longer, curved fascicles. Here, we test the validity and reliability of the EFOV-US method for obtaining fascicle lengths in the extensor carpi ulnaris (ECU). Fascicle lengths from images of the ECU captured in vivo with EFOV-US were compared to lengths from a well-established method, T-US. Images were collected in a joint posture that shortens the ECU such that entire fascicle lengths were captured within a single T-US image. Resulting measurements were not significantly different (p = 0.18); a Bland-Altman test demonstrated their agreement. A novice sonographer implemented EFOV-US in a phantom and in vivo on the ECU. The novice sonographer's measurements from the ultrasound phantom indicate that the combined imaging and analysis method is valid (average error = 2.2 ± 1.3 mm) and the in vivo fascicle length measurements demonstrate excellent reliability (ICC = 0.97). To our knowledge, this is the first study to quantify in vivo fascicle lengths of the ECU using any method. The ability to define a muscle's architecture in vivo using EFOV-US could lead to improvements in diagnosis, model development, surgery guidance, and rehabilitation techniques.

Original languageEnglish (US)
Pages (from-to)179-185
Number of pages7
JournalJournal of Biomechanics
StatePublished - Oct 3 2017


  • Fascicle length
  • Forearm
  • Muscle architecture
  • Skeletal muscle
  • Ultrasonography

ASJC Scopus subject areas

  • Biophysics
  • Rehabilitation
  • Biomedical Engineering
  • Orthopedics and Sports Medicine


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