( Sternotomy ( ( requires ( ( ( the use ) ( of ( a sternal ) ) ) ( ( ( saw ( to ( divide ( the sternum ) ) ) ) and ) ( requires ( spreading ( of ( ( ( the ( divided portions ) ) ( of ( ( the sternum ) ( with ( a ( sternal retractor ) ) ) ) ) ) ( to ( allow ( for ( ( ( ( ( ( visualization ( of ( the ( thoracic structures ) ) ) ) , ) ( passage ( of ( instruments ( into ( the chest ) ) ) ) ) ) , ) and ) ( removal ( of specimens ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Sternotomy)) (VP (VBZ requires) (SBAR (S (NP (NP (DT the) (NN use)) (PP (IN of) (NP (DT a) (NN sternal)))) (VP (VP (VBD saw) (S (VP (TO to) (VP (VB divide) (NP (DT the) (NN sternum)))))) (CC and) (VP (VBZ requires) (S (VP (VBG spreading) (PP (IN of) (NP (NP (DT the) (VBN divided) (NNS portions)) (PP (IN of) (NP (NP (DT the) (NN sternum)) (PP (IN with) (NP (DT a) (JJ sternal) (NN retractor))))) (S (VP (TO to) (VP (VB allow) (PP (IN for) (NP (NP (NP (NN visualization)) (PP (IN of) (NP (DT the) (JJ thoracic) (NNS structures)))) (, ,) (NP (NP (NN passage)) (PP (IN of) (NP (NP (NNS instruments)) (PP (IN into) (NP (DT the) (NN chest)))))) (, ,) (CC and) (NP (NP (NN removal)) (PP (IN of) (NP (NNS specimens)))))))))))))))))) (. .)))
Sternotomy requires the use of a sternal saw to divide the sternum and requires spreading of the divided portions of the sternum with a sternal retractor to allow for visualization of the thoracic structures, passage of instruments into the chest, and removal of specimens.
(ROOT (S (NP (DT The) (NN sternum)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (IN of) (NP (NP (DT the) (JJ elongated) (NN bony) (NN structure)) (SBAR (WHNP (WDT that)) (S (VP (VBZ anchors) (NP (DT the) (JJ anterior) (JJ thoracic) (NN cage))))))))) (. .)))