Moment arms of the arm muscles at the glenohumeral joint using the tendon excursion method

Eiji Itoi, Seok Beom Lee, Lawrence J. Berglund, Fredrick M. Schultz, Patricia G. Neale, Kai Nan An

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Muscle moment arm defines the function of the muscle. To date, moment arms of the arm muscles at the glenohumeral joint using the tendon excursion method have not been reported. As the functions of these muscles at the shoulder joint are controversial, this study was undertaken to determine the moment arms of the long and short heads of the biceps (LHB, SHB), the coracobrachialis, and the long head of the triceps muscles. The moment arms were determined in 10 cadaveric shoulders by measuring the tendon excursion when the arm was rotated by 1 radian (57.3°) in 22 different motions. The LHB was a flexor, horizontal flexor, and abductor. The SHB and coracobrachialis were flexors, horizontal flexors, and adductors. The long head of the triceps was an extensor and adductor. Arm rotation significantly affected the function of the LHB only: it was an internal rotator in flexion and an external rotator in abduction. This study clarifies the individual function of the arm muscles at the glenohumeral joint.

Original languageEnglish
Pages (from-to)45-53
Number of pages9
JournalJournal of Musculoskeletal Research
Volume11
Issue number2
DOIs
Publication statusPublished - 2008 Oct 6
Externally publishedYes

Keywords

  • Biceps brachii
  • Muscle function
  • Shoulder biomechanics

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

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