The cardiac apex and its superficial blood supply.

The cardiac apex was defined and 3 types were presented: the anatomical apex, the base of which was established at the incisura apicis cordis; the amplified anatomical apex, twice the volume of the preceding; and the geometric apex, the distal third of the ventricles. These types of cardiac apex were studied in connection with the superficial branches of the coronary arteries at their level. The investigation was conducted on 81 normal hearts (56 males and 25 females) of 60 Caucasian and 21 non-Caucasian individuals. The arteries were injected with colored gelatine mixed with a radiopaque substance. The number of branches decreased from the geometric (the largest type) to the anatomical apex (the smallest): 27 on the surface of the geometric apex, 14 on the surface of the amplified anatomical apex, and 7 on the surface of the anatomical apex. The sternocostal aspect had a higher number of superficial branches than the diaphragmatic aspect in all types of cardiac apex. Sexual differences were found in the incidence of the r posterior ventriculi sinistri intermedius on the amplified anatomical apex as it was more frequent in females than in males. In the geometric apex there were 3 branches also more frequent in females: r anterior ventriculi sinistri inferior, r posterior ventriculi sinistri lateralis I, and r posterior ventriculi sinistri lateralis IV.