area of cardiac dullness vs pectus

area of cardiac dullness and pectus both are nouns.

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

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