MUSCULAR ARCHITECTURE OF THE HUMAN HEART 229 



ficial. The ligaments that attach themselves to the aorta are the 

 aortic septum, the valves as well as two fibrous rings, one of which 

 encircles the right ostium venosum and the other the left. The 

 bicuspid and tricuspid valves are attached partly to the fibrous 

 rings and partly to the septum aorticum. Through them the papil- 

 lary muscles are attached to the tendinous structure in the base 

 of the heart. These all tend to the tie firmly the muscle bundles 

 to the aorta, towards which they force the blood in contracting, 

 and were it not so the force of contraction might '^ shoot the aorta 

 out of the heart." The two rings encircling the ostia venosa unite 

 over the septum of the ventricle into a single band and continue 

 into the membranous septum. Here they form the posterior 

 fibrous triangle, which is very pronounced in the pig. So it may 

 be seen that the aorta is held in place by three ligaments all of 

 which are extensions of the septum aorticum. They correspond 

 to the three semilunar valves of the aorta and also mark the tri- 

 gona fibrosa of the B N A. 



I shall describe them (1) as the posterior one which is an exten- 

 sion of the membranous septum backward between the venous os- 

 tia."*^ It forms the posterior fibrous triangle and to it are attached 

 the medial cusp of the tricuspid valve and the anterior cusp of the 

 bicuspid valve.^2 At the point of attachment of this ligament to 

 the aorta the atrio-ventricular bundle of His perforates the mem- 

 branous septum to enter the left ventricle. This ligament expands 

 into that portion of the wall of the aorta which lies opposite the 

 posterior semilunar valve.^^ (2) The left ligament^^ marks the 

 fibrous triangle to the left of the aorta opposite the left leaflet of 

 the semilunar valve immediately below the left coronoary artery. 

 The left ligament appears to have nothing to do with the aortic 

 septum. The left fibrous ring to which the bicuspid valve is 

 attached arises from left and the posterior ligaments of the aorta. 

 (3) The right ligament encircles the right side of the aorta opposite 

 the right cusp of the aortic valve below the right coronary artery. 



" Poirier and Charpy, Tome 2, fig. 360, nodule droit. 

 « See Spalteholz's Atlas, 1896, fig. 419. 



« Note that the B N A as used for this valve, improperly called the right semi- 

 lunar value by English anatomists. 

 ^■^ Nodule gauche. 



