Cross Section Of Vein

Lining the core of each is a thin layer of endothelium and covering each is a sheath of connective tissue but an artery has thick intermediate layers of elastic and muscular fiber while in the vein these are much thinner and less developed. The more constant cross veins are the humeral cross vein h between costa and subcosta the radial cross vein r between r and the first fork of rs the sectorial cross vein s between the two forks of r8 the median cross vein m m between m2 and m3 and the mediocubital cross vein m cu between media and cubitus. See bp4527 and bp4529 for others in the series.