Development of spatial relations of shoulder and brachium in embryonal chick wing.

Abstract

The linear marking method was employed to study morphogenetic movements of tissues involved in the development of the definitive position and shaping of the shoulder and arm. Chick embryos in the range of embryonal day 3.5 to 4.5 were used with the following results: -Asymmetrical growth of the early wing bud and the oblique position of humerus anlage in the early wing bud as proposed by Saunders (1948) and Seichert (1965) were confirmed. -It was found that the cranial ascend of the shoulder (Seichert and Knospe 1992) is accompanied by the slight ventromedial rotation of the complex consisting of the scapula and coracoid. -Torsion along the longitudinal axis of the stylopodium was observed: the proximal part of the stylopodium (both the humerus anlage and related soft tissues) moves in the sense of supination, the distal part moves in the sense of pronation.