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Thorax
Published in David Heylings, Stephen Carmichael, Samuel Leinster, Janak Saada, Bari M. Logan, Ralph T. Hutchings, McMinn’s Concise Human Anatomy, 2017
David Heylings, Stephen Carmichael, Samuel Leinster, Janak Saada, Bari M. Logan, Ralph T. Hutchings
Chambers and great vessels - the right atrium (Fig.5.9) receives venous blood mainly from the superior vena cava and the inferior vena cava, but also from the coronary sinus (see below), the main vein of the heart itself and some other small veins. The internal wall is largely smooth, although there is a rough walled part separated from the smooth wall by a ridge, the crista terminalis, marked externally as a groove, the sulcus terminalis. The rough wall ridges are known as the musculi pectinate and extend out from the crista into the right atrial appendage and represent the primitive atrium of the heart. Internally, on the smooth wall just above the inferior vena cava beside the opening of the coronary sinus, is a shallow depression, the fossa ovalis (Fig. 1.3), lying on the interatrial septum, representing the remnants of the foramen ovale (a right to left interatrial shunt in foetal life). The blood passes from the atrium through the tricuspid valve (Fig.5.11) into the right ventricle, then through the pulmonary valve (Fig.5.12) into the pulmonary trunk, and so to the right and left pulmonary arteries, conveying deoxygenated blood from the right ventricle to the lungs.From the lungs, oxygenated blood is carried by the pulmonary veins (usually two on each side) to the left atrium (Figs.5.12, 5.14B) and then passes through the (bicuspid) mitral valve into the left ventricle (Fig.5.13), from where it leaves through the aortic valve to enter the aorta, the body’s largest vessel. The wall of the left ventricle is thicker (almost four times) than that of the right ventricle (Fig.5.14) because the pressure of blood in the systemic circulation is much greater than that in the pulmonary circulation.
Patent foramen ovale and cryptogenic stroke: contemporary evidence and treatment
Published in Expert Review of Cardiovascular Therapy, 2018
J. J. Coughlan, Aidan Daly, Samer Arnous, Tom J. Kiernan
As seen in the figure adapted from Konstantinides et al. [7] (Figure 1), the atrium begins as a single cavity. At around 28 days, a crest of tissue, which is the beginning of the septum primum, leaves the cephalic part of this primitive atrium and grows caudally, toward the endocardial cushion. This is the beginning of the division of the primitive atrium into two separate cavities, the left and right atria. The gap between the septum primum and endocardial cushion is known as the ostium primum.