The sinus node.

This discussion of the sinus node begins with a description of its normal anatomy, particularly in the human heart, and then proceeds to a review of the several pathologic changes known to affect the sinus node. The latter include diseases of the sinus node artery, changes in the normal collagen framework of the node, pericarditis and certain infiltrative processes. The concluding section combines an examination of function and structure of the sinus node on the basis of experimental observations. Some new laws of the heart dealing with governance of normal cardiac rhythm are presented.