( ( A ( medical instrument ) ) ( ( called ( ( a sphygmomanometer ) ( is ( used ( to ( ( measure ( the pressure ) ) ( within ( your arteries ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ medical) (NN instrument)) (VP (VBD called) (SBAR (S (NP (DT a) (NN sphygmomanometer)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (DT the) (NN pressure)) (PP (IN within) (NP (PRP$ your) (NNS arteries))))))))))) (. .)))
A medical instrument called a sphygmomanometer is used to measure the pressure within your arteries.
(ROOT (S (NP (NNP Sphygmomanometer)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NN blood) (NN pressure))))))) (. .)))