Does reaching the back reflect the actual internal rotation of the shoulder?

Ikuko Wakabayashi, Eiji Itoi, Hiroshi Minagawa, Moto Kobayashi, Nobutoshi Seki, Yoichi Shimada, Kyoji Okada

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


To clarify the relationship between the vertebral level reached by the thumb and the internal rotation angle of the humerus, 7 shoulders in healthy volunteers were examined by use of an electromagnetic tracking device. Measurements were repeated in the hanging-arm position with the thumb pointing anteriorly and at the buttock, sacrum, and each vertebral level up to T6. From the hanging-arm position to the buttock, 54.3% of internal rotation occurred (mean, 39.8°), and from the buttock to the sacrum, 11.7% occurred (mean, 8.6°). In total, 66% of internal rotation occurred from the hanging-arm position to the sacrum. Above the sacrum, the contribution of elbow flexion to the level of the vertebral spine became much greater, and internal rotation of the shoulder did not change significantly above the T12 level. We recommend that the level of the thumb below the buttock be subdivided for more accurate assessment of internal rotation.

Original languageEnglish
Pages (from-to)306-310
Number of pages5
JournalJournal of Shoulder and Elbow Surgery
Issue number3
Publication statusPublished - 2006 May 1
Externally publishedYes

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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