Platelet adhesion to collagen occurs :
Platelet adhesion to collagen occurs von-Willebrand factor)Endothelial injury allows platelets to contact the underlying extracellular matrix; subsequent adhesion occurs through interactions with von Willebrand factor (vWF), which is a product of normal endothelial cells and an essential cofactor for platelet binding to matrix elements.
Factor VIII
Factor IX
von Willebrand factor
Fibronectin