The anatomy of the aortic root.

The aortic root is the anatomical bridge between the left ventricle and the ascending aorta. It is made up of the aortic valve leaflets, which are supported by the aortic sinuses (of Valsalva), and the interleaflet triangles interposed between the basal attachments of the leaflets. As such, it possesses significant length, and because of the semilunar attachment of the leaflets, there is no discrete proximal border to the root. It is limited distally, nonetheless, by the supravalvar ridge, or sinutubular junction. Descriptions of the aortic root over the years have been bedeviled by accounts of a valve anulus. There are at least two rings within the root, but neither serves to support the valve leaflets, each leaflets being attached in semilunar fashion from the sinutubular junction to a basal ventricular attachment Two leaflets are supported by muscle, and the third has an exclusively fibrous attachment. The root acts as a bridging structure not only anatomically, separating the myocardial and arterial components of the left ventricular pathway, but also functionally, since its proximal and distal components can withstand considerable changes in ventricular and arterial pressures. In this review, we describe the anatomy of this crucial cardiac component, emphasizing the current problems which have arisen due to indiscriminate descriptions of a nonexistent anulus.

Cardiac veins: a review of the literature.

Cardiac veins have long stood in the shadow of their more extensively studied counterparts, the coronary arteries. The clinical importance of the coronary venous system, nonetheless, should not be underestimated. Intricate and beneficial therapeutic options are increasingly being developed that depend on knowledge of the structure of this venous network. Such interventions have been shown greatly to promote cardiac health, and to enhance the efficacy of cardiac pacing. A comprehensive appreciation of the architecture of the coronary venous system, therefore, is crucial to optimal cardiac care. It is possible to provide an overview of the arrangement of the cardiac veins, with the larger veins draining to the coronary sinus, and thence to the right atrium, but with smaller and minimal veins draining directly to the cavities of the atrial chambers. The venous pathways, nonetheless, are highly variable, making exceptions the commonly accepted rule. As such, unique solutions for imaging, and simple attentiveness to possible venous variations, can greatly enhance clinical outcomes. For example, identifying the diameter, course, and valves of the cardiac veins allows for anticipation of impediments during interventional procedures, and allows for informed clinical decision-making. Also of significance is awareness of alternate arrangements that may be encountered in terms of venous drainage, and the importance of intramural venous collecting spaces in these patterns. The objective of our review, therefore, is to explore and describe the anatomical distribution of the coronary veins.

The clinical anatomy of the coronary collateral circulation.

Although the structure and function of the coronary vasculature has been exhaustively studied, it still holds significant elements of mystery for the researcher and clinician. This is particularly true regarding the structure and function of the human collateral coronary circulation. Controversy still exists concerning the pathways of collateral vessels as well as their function. Controversies also exist relative to the methods used to delineate the pathways, these being additionally compounded by the lack of standardization of the studies and measurements. In this review, we summarize our current knowledge of this functionally significant vascular network.