Assertion: papillary muscle | /r/CapableOf | prevent backward expulsion
Facets:
value: into the atria
type: TRANSITIVE-OBJECT
Source sentences:
text: The papillary muscles prevent backward expulsion into the atria.
text: The papillary muscles are extensions of the myocardium that pull the cusps together and downward at the onset of ventricular contraction, thus preventing their backward expulsion into the atria.