part of start stage end stage trabecular layer of ventricle cardiac muscle tri-tipped trabecula Cardiac muscle located in the trabecular layer of the ventricle that is attached to the base of the AV and BV valves. It is similar to the papillary muscle in mammals and birds but, does not attach to the ends of the valve leaflets. 2015-02-19T03:45:32Z Ceri zebrafish_anatomy ZFA:0005826 larval:protruding-mouth adult