Henry Gray (18251861). Anatomy of the Human Body. 1918. groove);
this contains the trunks of the nutrient vessels of the heart,
and is deficient in front, where it is crossed by the root of
the pulmonary artery. The interatrial groove, separating the two
atria, is scarcely marked on the posterior surface, while
anteriorly it is hidden by the pulmonary artery and aorta. The
ventricles are separated by two grooves, one of which, the
anterior longitudinal sulcus, is situated on the sternocostal
surface of the heart, close to its left margin, the other
posterior longitudinal sulcus, on the diaphragmatic surface near
the right margin; these grooves extend from the base of the
ventricular portion to a notch, the incisura apicis cordis, on
the acute margin of the heart just to the right of the apex. The
base (basis cordis) (Fig. 491), directed upward, backward, and
to the right, is separated from the fifth, sixth, seventh, and
eighth thoracic vertebræ by the esophagus, aorta, and thoracic
duct. It is formed mainly b