Anatomical study of the muscles of the shoulder, arm and forearm in three species of wild birds

In the past many authors have focused on the anatomical study of the wing in order to correlate anatomical details with the peculiarities of flight in different species. In spite of the limited information about the anatomy of the thoracic limb in European avian species, we decided to investigate these structures in three species presenting a different kind of flight spread throughout the Italian territory: the Grey Heron (Ardea cinerea), the Eurasian Buzzard (Buteo buteo) and the Common Kestrel (Falco tinnunculus). Therefore we performed a stratigraphic dissection of the wing in different subjects of the species examined. Comparing the results of this study with those found in literature for similar species, we observed many peculiarities which have not previously been described. The most relevant was that involving the Coracobrachialis caudalis muscle, the scapular and humeral anchor and the Extersor radialis carpi muscle. The Coracobrachialis caudalis muscle in the Grey Heron is composed of two different heads instead of the typical one observed by Vanden Berge (1970) in other Ciconiiformes. Regarding the scapular and the humeral anchor the different development found through the species suggests a correlation between these structures and the kind of flight. Concerning the Extersor radialis carpi muscle, the differences we found in the number of bellies could support Nair’s hypothesis (1954) about a correlation between the heads of this muscle and different type of flights such as soaring of flapping. These deductions should be confirmed by further studies in wind tunnel and electromyography.