pectus vs area of cardiac dullness

pectus and area of cardiac dullness both are nouns.

Word	Noun	Adjective	Verb	Adverb
pectus	Yes	No	No	No
area of cardiac dullness	Yes	No	No	No

pectus (noun)	area of cardiac dullness (noun)
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates	a triangular area of the front of the chest (determined by percussion); corresponds to the part of the heart not covered by the lungs