The structure and elastic properties of arterial junctions.

Light microscopic studies showed marked differences in the elastin pattern at aorto-branch junctions on the proximal and distal lips of the junctions, both for small elastic branches such as the intercostals, and for the large muscular branches arising from the abdominal aorta. A light-pipe method showed that the internal apical curvature of translucent human cerebral arteries became flatter as the pressure increased. Longitudinal strips of aorto-branch junctions from sheep and dogs were stretched at known strain rates. There appear to be differences in the two species as the flow divider is least distensible in sheep and most distensible in dogs. Scanning electron microscopy of NaOH-digested arteries showed that the internal elastic membrane is a fenestrated sheet, the adventitia has fibrous elastin, and the medial layers are transitional. There are many interlamellar connections.