[Treatment of the combined musculus trapezius/serratus anterior paresis with scapulothoracal arthrodesis according to Spira (author's transl)].

The combined paresis of the musculus trapezius and musculus serratus anterior results in a positional change and major loss of active mobility of the shoulder girdle. This greatly disturbs the mechanics of movement of the upper arm. The individual signs include a lowering of the shoulder blade in ventro-caudal direction in accordance with the weight of the arm, as a result of the absence of muscular restraint. In this position, the scapula exercises so to say an adducting action on the upper arm, so that this will usually not exceed an abduction of about 40 degrees, in relation to the perpendicular line of C7, althoug it may be freely mobile in the glenohumeral joint. Increase of elevation of the upper arm and of the force exercised by the musculature acting on the glenohumeral joint can be achieved via a correction of the position of the shoulder girdle associated with simultaneous stabilization of the shoulder blade at the posterior thoracic wall. Using an actual case as basis, scapulothoracic arthrodesis in the modification according to Spira is described as a method to correct the position of the shoulder blade and to stabilize the scapula. Other possibilities of stabilization in the form of musculature transpositions and paresis operations are discussed. The article also comments on the indication of scapula fixation.