Major Questions about Teres Minor: The Pattern of Reactive Changes in a Precolumbian Human Skeletal Sample From Illinois

Abstract

The ubiquitous presence of reactive changes at the insertion of a minor muscle of the rotator cuff on the proximal humerus (teres minor) is analyzed in an adult Late Woodland (AD 800–1150) period osteological sample (N = 43) from west-central Illinois (Schroeder Mounds, 11HE177). Fifty-seven percent left (20/35) and sixty-nine percent right humeri (25/36) have reactive change to the t. minor facet. There are no statistically significant differences by sex or side asymmetry. Reactive change generally co-associates with greater humeral robusticity. Besides a minor collaborative role in shoulder joint stability, teres minor has a limit range of movement as an abductor and external rotator of the arm. Injuries to the t. minor are exrememly rare in modern clinical contexts and only in athletes who engage in actvivites that utilize overhead arm movements. That is, the reactive change may be associated with particular arm movements or body posture which, in this pre-Columbian horticulturalist sample, may be related to activities for which there are no modern clinical correlates.