( ( ( pulmonary or ) pulmonic ) ( ( -LRB- ( valve -RRB- ) ) ( ( ( stenosis ( ( Pathological narrowing ) ( of ( the ( heart valve ) ) ) ) ) ( which ( normally ( ( prevents ( backflow ( of ( ( oxygen-poor blood ) ( from ( the ( main ( pulmonary artery ) ) ) ) ) ) ) ) ( into ( the ( right ventricle ) ) ) ) ) ) ) . ) ) )
(ROOT (SINV (ADJP (JJ pulmonary) (CC or) (JJ pulmonic)) (PRN (-LRB- -LRB-) (VB valve) (-RRB- -RRB-)) (VP (VBZ stenosis) (NP (NP (JJ Pathological) (NN narrowing)) (PP (IN of) (NP (DT the) (NN heart) (NN valve))))) (SBAR (WHNP (WDT which)) (S (ADVP (RB normally)) (VP (VBZ prevents) (NP (NP (NN backflow)) (PP (IN of) (NP (NP (JJ oxygen-poor) (NN blood)) (PP (IN from) (NP (DT the) (JJ main) (JJ pulmonary) (NN artery)))))) (PP (IN into) (NP (DT the) (JJ right) (NN ventricle)))))) (. .)))
pulmonary or pulmonic (valve) stenosis Pathological narrowing of the heart valve which normally prevents backflow of oxygen-poor blood from the main pulmonary artery into the right ventricle.
(ROOT (S (NP (NNP Heart) (NNS valves)) (VP (VBP prevent) (NP (NP (DT the) (NN backflow)) (PP (IN of) (NP (NN blood)))) (PP (IN from) (S (VP (VBG happening) (PP (IN in) (NP (DT the) (NN heart))))))) (. .)))