“The dicrotic elevation at different points of the arterial tree”

In a number of dogs the form of the pulse-wave was studied by means of the Hürthle manometer. The arteries upon which the observations were made were the following—aorta, brachiocephalic, innominate, carotids, thyroids, vertebrals, internal mammaries, axillaries, brachials, left subclavian, celiac axis, superior mesenteric, left renal, inferior mesenteric, left iliac, deep femoral, femoral, saphenous and peripheral end of the carotid, i. e., a side branch of the circle of Willis. The exact values of the apex and base of the pressure triangles were determined from readings of the systolic and diastolic pressures obtained by means of a valved manometer.

A careful study and comparison of the results has led to the following conclusions.

1. In passing from the heart to the periphery the dicrotic elevation increases in distinctness and in the special case of the aotrtico-femoral system the dicrotic elevation occurs lower on the catacrotic limb of the fundamental wave. On the other hand as the arteries decrease in size, the dicrotic elevation soon disappears, e. g., in the thyroid, saphenous and so forth. Consequently there is in every system of arteries (aorticofemoral, brachiocephalic and left subclavian) a region lying somewhere between the aortic arch and the periphery in which the dicrotic elevation is maximal.

2. In the aorticofemoral system the side pulse shows a maximal dicrotic wave between the origin of the renal and that of the deep femoral artery; in the brachiocephalic system, between the origin of the carotids and that of the vertebral or thyroid artery; in the left subclavian system the dicrotic wave is less pronounced in the mammary than in the vertebral artery and consequently the maximum in question must lie central from the origin of the former artery. In the case of the end pulse, the region of the maximal dicrotic wave is in or peripheral to the brachial, femoral and carotid arteries but it is impossible to say whether the maximum occurs in them or peripheral to them, because they were the most peripheral of the arteries examined in this connection.