[Evolutionary significance of reciprocal biological effects of form and function using the example of the scapula in...

The shoulder-blades of 99 catarrhine primates were investigated metrically and morphologically. In order to obtain comparable data, each analysed shoulder-blade was orientated in the same way in a 3-dimensional coordinate system. With the help of a diopthograph, the 3 planes were drawn without distorsion. On these planes the dimensions and angles were measured. These method produced the advantages of taking homologues data as well as of being able to compare the morphological data and its variability. Within the catarrhine primates, the area of the scapula (Fossa infra- and supraspinata) correlates highly significant with the body weight. Regarding the proportions and dimensions of the area of the scapula, there is no difference between the gibbons and the monkeys, regarding the dimensions, proportions and angles of the processes (acromion and coracoid) as well as the vertebral border of the scapula, the gibbons are close to the great apes. The areas of the shoulder-blades of the monkeys, where the shoulder stabilizing muscles originates, are fundamentally equal to each other. Whether body weight nor locomotion have an essential influence on its shape and structure (excl. Mandrillus). On the other hand, the variability of the joint area is considered and the processes are small. The gibbons, the great apes, and men are highly variable regarding the dimensions and the proportions of the area of the shoulder-blades. Regarding the dimensions, proportions, and angles of the acromion and the coracoid, where the shoulder joint stabilizing muscles originate, as well as the vertebral border, there are no fundamental differences between them and the processes are large and robuste.