Características biomecânicas da articulação escapulotorácica no retorno da elevação dos membros superiores: uma revisão crítica da literatura

Abstract

Clinical observations have shown that patients with disorder of the shoulder joint complex describe the lowering of the arms to be more painful than its raising. The scapulothoracic joint has an important role in the understanding of the shoulder joint complex kinematics and muscle activity, as well as in the specific features during the lowering of the arms. Therefore, the aim of this study was to conduct a critical review about the biomechanical characteristics of the scapulothoracic joint during the lowering of the arms in healthy subjects and subjects with shoulder disorders. A computerized search was performed in MEDLINE, SCIELO, LILACS and PEDro databases. Hand search was also conducted and, after reading the full texts, fourteen studies remained eligible to be included according to the inclusion criteria previously established. Among the included studies, eight have investigated kinematic characteristics and six presented electromyography characteristics. Two studies analyzed both characteristics and, only two showed results related to individuals with shoulder disorders. The results of these studies showed that during the lowering of the arms, the three-dimensional movements of the scapulothoracic joint involved a combined movement of downward rotation (perpendicular axis to the scapular plane), anterior tilt (medial-lateral axis) and internal rotation (vertical axis) in the frontal (lowering of arm abduction), sagittal (lowering of arm flexion) and scapular planes. Thus, the lowering of the arms is considered to be a reverse movement of the scapulothoracic movements during arm elevation. However, there are significant differences in angular positions of the scapulothoracic joint when compared to arm elevation, mainly in the downward rotation and tilt movements. The isolated scapulothoracic muscles activity and its co-activation reduce gradually during the lowering of the arms and present lower values when compared to the elevation phase. The lack of studies that assess the biomechanical characteristics of the scapulothoracic joint in individuals with shoulder disorders limits the understanding of kinematics and muscle activity in this specific population.