( Triceps ( ( ( Muscle ( at back ) ) ( of ( ( upper arm ) ( which ( extends ( the arm ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Triceps)) (VP (VBP Muscle) (ADVP (IN at) (RB back)) (PP (IN of) (NP (NP (JJ upper) (NN arm)) (SBAR (WHNP (WDT which)) (S (VP (VBZ extends) (NP (DT the) (NN arm)))))))) (. .)))
Triceps Muscle at back of upper arm which extends the arm.
(ROOT (S (NP (DT The) (NNS triceps)) (VP (VBP help) (S (NP (DT the) (NN body)) (VP (VB extend) (NP (DT the) (NN arm))))) (. .)))