Muraki T, Aoki M, Uchiyama E, Takasaki H, Murakami G, Miyamoto S. A cadaveric study of strain on the subscapularis muscle. Objectives: To measure the strain on 3 fiber groups of the subscapularis muscle at various glenohumeral joint positions and to determine the appropriate shoulder position for subscapularis muscle stretching. Design: Repeated-measures design. Setting: Biomechanics laboratory. Specimens: Nine frozen-thawed glenohumeral joints obtained from 9 fresh cadavers. Interventions: Not applicable. Main Outcome Measure: The strain on the upper, middle, and lower fiber groups of the subscapularis were measured by precise displacement sensors during 14 different glenohumeral joint positions. Results: The glenohumeral joint position that showed the largest strain varied among the 3 fiber groups. Although no position showed significantly large strain on the upper and middle fiber groups, external rotation at 30°, 60°, and 90° of elevation, abduction, flexion, and horizontal abduction revealed significantly greater strain on the lower fiber groups (P<.005). Additionally, except for external rotation at 0° of elevation, the strain on the lower fiber group was significantly greater than that on the upper and middle fiber groups in external rotation (P<.005). Conclusions: The stretching position of each fiber group of the subscapularis differs depending on the glenohumeral joint position. External rotation at 30° to 60° of glenohumeral elevation, abduction, flexion, and horizontal abduction can significantly stretch the lower fiber group of the subscapularis muscle. © 2007 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.
Muraki, T., Aoki, M., Uchiyama, E., Takasaki, H., Murakami, G., & Miyamoto, S. (2007). A Cadaveric Study of Strain on the Subscapularis Muscle. Archives of Physical Medicine and Rehabilitation, 88(7), 941–946. https://doi.org/10.1016/j.apmr.2007.04.003