Subatrial papillary muscle

The subatrial papillary muscle (also identified as "posterior papillary muscle" by human nomenclature) arise near the caudal mural aspect of LV and lies near the subsinuosal interventricular groove. The subatrial papillary muscle (musculus papillaris subatrialis) is closer to the paraconal interventricular groove that the subauricular papillary muscle.

The two large papillary muscles (musculi papillares) of the left ventricle are thick, smooth rolls of myocardium, coming from the LV outer wall which have compound apices and give rise to the stout chordae tendineae of this chamber.