The papillary muscles of the left ventricle and the cardiac segments.

The relationship between the arterial anatomicosurgical segments and the papillary muscles of the left ventricle was investigated in 38 human hearts of adult individuals of both sexes. The specimens were studied after (a) vinyl acetate injection and corrosion (28 hearts) or (b) formaldehyde fixation (10 hearts). In 4 of the corrosion casts, the cardiac chambers were not filled with the plastic substance and, prior to corrosion, the position of the papillary muscles was marked with threads or pins. The anterior papillary muscle was related to the (a) anterior interventricular segment (I SV); (b) lateral (II SV); and (c) left marginal segment (III SV). The medical portion of the anterior papillary muscle is supplied by the artery of the I SV whereas the lateral portion is supplied by the artery of the II or III SV. The posterior papillary muscle was related to the (a) anterior interventricular segment (I SV); (b) left marginal (III SV); (c) posterior interventricular segment (III DV) and (d) posterior ventricular (IV SV). As a rule, the papillary muscles are supplied by more than one segmental artery, therefore, anatomical variations may play an important role in functional alterations produced by ischemic lesions of the myocardium.