Contribution to the topographic and macroscopic anatomy of the equine shoulder joint

A total of 31 equine shoulder joints was investigated macroscopically and w ith help of corrosion costs. At the medial side of the scapula close to the Proc. supraglenoidalis a sme ll groove can be found, the sulcus supraglenoidalis. It is caused by the co urse of the supraspinatus muscle which posses over the proc. supraglenoidal is. The articular surface of the glenoid cavity is incised craniomedially ( incisura cavitatis glenoidalis). In the very centre of the glenoid cavity a small depression (foveola cavitatis glenoidalis) can be found. The humeral articular facet shows a corresponding notch at the craniomedial side oppos ite to the glenoid incision [Incisura faciei articularis capitis humeri). T he cranial limitation of the humeral joint facet is formed by the crista ca pitis humeri. This crest arises in the area of insertion of the lateral and medial glenohumeral ligaments. Three cranial socks of the joint capsule as described by other authors coul d also be found in this investigation. In contrast to the literature in all articular corrosion casts performed during this study, one caudal sock exc lusively was observed. This caudal sack is situated caudolateral and distal to the joint gap. The joint capsule displays two distinct bundles of collagen fibres reinforc ing its fibrous layer: The ligamentum glenohumerale mediate travels from it s origin distal of the tuberculum supraglenoidale to the tuberculum minus h umeri. The lateral glenohumeral ligament, which is significantly stronger t han the medial ligament, divides into two parts. The cranial of these inser ts near the pars cranialis of the greater tubercle while the other ends in the vicinity of the pan caudalis. The double heeded m. articularis humeri originates from the distal end of t he caudal scapular margin and is attached to the humerus by a thin tendon p late penetrating the muscle body of the m. brachialis. The articular muscle serves as a protection for the joint capsule, especially when the shoulder joint is bent. On the one hand this is due to the fact that its belly is c losely attached to the articular capsule, on the other hand this muscle cou rses like the tendon of a bow which allows to pull the capsule in caudal di rection.