The medial papillary complex.

The anatomy of the papillary muscle of the conus, also known as Lancisi's muscle, was studied in 100 normal hearts from pathological collections and in 8 embryonic and fetal hearts. Wide morphological variations were observed and because of this the name medial papillary complex is proposed. It is concluded that the value of this complex as an anatomical landmark in the right ventricle is a very restricted one. The development of the medial papillary complex is described.