How does the morphology of the scapula affect the line of action of the rotator cuff muscles and is it a risk factor for developing a throwing shoulder?

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K19834
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59010:Rehabilitation science-related
• Research Institution: Sapporo Medical University
• Principal Investigator: Toda Hajime 札幌医科大学, 保健医療学部, 講師 (40516580)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 骨形態 / 投球障害肩 / 肩甲骨 / 回旋筋腱板 / 画像解析

Outline of Final Research Achievements

Morphological variations in the scapula have been discussed as potentially correlating with the risk of developing throwing shoulder. In this study, we validated the method of measuring scapular bone morphology and investigated whether differences in scapular bone morphology were associated with a history of throwing shoulder. The results showed that the glenoid of baseball players without a history of shoulder injury tended to have greater retroversion and anterior torsion compared to baseball players with a history of shoulder injury and controls. These findings suggest that greater glenoid retroversion and anterior glenoid torsion may be adaptations to reduce the mechanical loading on the shoulder joint caused by the throwing motion.

Free Research Field

スポーツ理学療法学

Academic Significance and Societal Importance of the Research Achievements

これまで肩甲骨骨形態と投球障害肩の発症リスクの関連は十分な知見が確立されていなかった。本研究では「大きな関節窩後傾」や「大きな関節窩前捻」を持つ野球選手が投球障害肩の発症リスクを下げる可能性を示した。研究開始当初の目的である「骨形態に応じた機能的な予防プログラム」につながる知見は示せなかったが、投球動作への適応として重要となる骨形態的特徴が明確になり今後の検討につながる研究となった。