( ( In ( the ( patellar ( ( -LRB- ( or ( ( knee jerk ) -RRB- ) ) ) reflex ) ) ) ) ( , ( ( the calf ) ( ( extends ( on ( the thigh ) ) ) ; ) ) ) )
(ROOT (S (PP (IN In) (NP (DT the) (JJ patellar) (PRN (-LRB- -LRB-) (CC or) (NP (NP (NN knee)) (NP (NN jerk))) (-RRB- -RRB-)) (JJ reflex))) (, ,) (NP (DT the) (NN calf)) (VP (VBZ extends) (PP (IN on) (NP (DT the) (NN thigh)))) (: ;)))
In the patellar (or knee jerk) reflex, the calf extends on the thigh;
(ROOT (X (NP (DT The) (`` ``) (JJ knee-jerk) ('' '') (NN motion)) (SBAR (IN that) (S (NP (NNS people)) (ADVP (RB involuntarily)) (VP (VBP perform) (SBAR (IN after) (S (S (VP (VBG being) (VP (VBN struck) (PP (IN in) (NP (NP (DT the) (NN knee)) (PP (IN in) (NP (DT a) (JJ certain) (NN way)))))))) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (DT a) (JJ reflex))))))))))))