( ( ( ( ( migraine headache ) , ) ( ( common ( Definition ( A disorder ) ) ) ( involving ( repeated ( or ( recurrent headache ) ) ) ) ) ) , ) ( ( ( ( associated ( with ( temporary changes ) ) ) ( in ( diameter ( of ( the ( blood vessels ) ) ) ) ) ) ( in ( the head ) ) ) . ) )
(ROOT (S (NP (NP (JJ migraine) (NN headache)) (, ,) (NP (NP (JJ common) (NNP Definition) (NNP A) (NN disorder)) (VP (VBG involving) (NP (JJ repeated) (CC or) (NN recurrent) (NN headache)))) (, ,)) (VP (VBN associated) (PP (IN with) (NP (JJ temporary) (NNS changes))) (PP (IN in) (NP (NP (NN diameter)) (PP (IN of) (NP (DT the) (NN blood) (NNS vessels))))) (PP (IN in) (NP (DT the) (NN head)))) (. .)))
migraine headache, common Definition A disorder involving repeated or recurrent headache , associated with temporary changes in diameter of the blood vessels in the head.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (NN blood) (NNS vessels)) (PP (IN in) (NP (DT the) (NN head)))) (VP (VBP dilate)))) (, ,) (NP (NP (DT a) (NN migraine)) (, ,) (NP (DT a) (JJ severe) (NN headache)) (, ,)) (VP (MD can) (VP (VB occur))) (. .)))