Muscle activities during shoulder internal rotation differ in arm position: a preliminary quantitative analysis using positron emission tomography

Gaku Matsuzawa, Hirotaka Sano, Nobuyuki Yamamoto, Daisuke Kurokawa, Shoichi Watanuki, Manabu Tashiro, Eiji Itoi

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To investigate the muscle activity patterns of the glenohumeral joint during internal rotation both with the arm at 0° and 90° of abduction using 2-deoxy-2-[18F] fluoro-d-glucose (FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI). Materials and methods: Six healthy male volunteers underwent PET examination after performing active glenohumeral internal rotation exercise using an elastic band both with the arm at 0° and 90° of abduction. As a control, PET scan under resting condition was also performed. The exercise was performed before and after 18 fluorodeoxyglucose injection. Each PET image was fused to the corresponding MRI to identify each muscle. The standardized uptake value (SUV) of each muscle was compared between the two arm positions. Results: With the arm at 0° of abduction, the SUV increased significantly after exercise both in the middle and inferior 1/3 of the subscapularis, which were significantly higher than that of the superior 1/3 of the subscapularis (P < 0.05). The SUV of the inferior 1/3 of the subscapularis was significantly higher at 90° of abduction than at 0° of abduction and was significantly higher than that of the superior 1/3 at 90° of abduction (P < 0.01). The SUV after exercise in the inferior infraspinatus and teres minor increased. Conclusions: The middle and inferior parts of the subscapularis are the main shoulder internal rotators in 0° of abduction, whereas the inferior part of the subscapularis is the main internal rotator in 90° of abduction.

Original languageEnglish
Pages (from-to)1839-1847
Number of pages9
JournalSkeletal Radiology
Volume49
Issue number11
DOIs
Publication statusPublished - 2020 Nov 1

Keywords

  • Abduction
  • Adduction
  • Internal rotation
  • Positron emission tomography
  • Subscapularis

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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