We have shown previously by means of quail/chick transplantations that external and visceral organs, i.e., somatopleural and splanchnopleural derivatives, acquire their endothelial network through different mechanisms, namely immigration (termed angiogenesis) versus in situ emergence of precursors (or vasculogenesis). We have traced the distribution of QH1-positive cells in chick hosts after replacement of the last somites by quail somites (orthotopic grafts) or lateral plate mesoderm (heterotopic grafts). The results lead to the conclusion that the embryo becomes vascularized by endothelial precursors from two distinct regions, splanchnopleural mesoderm and paraxial mesoderm. The territories respectively vascularized are complementary, precursors from the paraxial mesoderm occupy the body wall and kidney, i.e., they settle along with the other paraxial mesoderm derivatives and colonize the somatopleure. The precursors from the two origins have distinct recognition and potentialities properties: endothelial precursors of paraxial origin are barred from vascularizing visceral organs and from integrating into the floor of the aorta, and are never associated with hemopoiesis; splanchnopleural mesoderm grafted in the place of somites, gives off endothelial cells to body wall and kidney but also visceral organs. It gives rise to hemopoietic precursors in addition to endothelial cells.

A fracture dislocation of the upper thoracic spine with spinal cord injury is reported in a neonate. This rare injury is associated with attendant predisposing obstetric circumstances (breech transverse presentations, large baby size) that can alert clinicians of potential problems and aid in the diagnosis of neonatal hypotonia and paralysis.

This study proves the real existence of a microvascular suprafascial axis formed by fibular perforator anastomoses and stretching over the entire length of the fibula, from the fibular head to the distal tip of the lateral malleolus. This suprafascial vascular axis could be an anatomical basis for a fasciocutaneous fibular flap.