The shoulder joint system: Biomechanics and instability

The joints of the shoulder number from four to five, depending on interpretation. Together, they form one of the most complex and mobile joint systems in the human body. In mechanical terms, "the shoulder joint system" is a mechanism with multiple degrees of freedom. The shoulder system provides a wide range of motion, to the detriment of stability. To a greater or lesser extent, instability characterizes all of the system's joints and in particular the glenohumeral joint, which has received most attention in the literature. Without going into the merits of surgical procedures and basic theoretical studies of a mechanical nature, in this work it is presented a review with comments of the methodological developments in biomechanics which can be useful in studying the instability of the entire joint system or its parts, and which can be of assistance in selecting which type of corrective surgery should be performed.