( Occasionally ( ( ( ( ( ( ( ( ( ( ( ( ( ( the spleen ) , ) heart ) , ) ( nervous system ) ) , ) bones ) , ) joints ) , ) and ) ( skeletal muscles ) ) ( also ( come ( under attack ) ) ) ) . ) )
(ROOT (FRAG (ADVP (RB Occasionally)) (NP (NP (NP (DT the) (NN spleen)) (, ,) (NP (NN heart)) (, ,) (NP (JJ nervous) (NN system)) (, ,) (NP (NNS bones)) (, ,) (NP (NNS joints)) (, ,) (CC and) (NP (JJ skeletal) (NNS muscles))) (VP (ADVP (RB also)) (VBN come) (PP (IN under) (NP (NN attack))))) (. .)))
Occasionally the spleen, heart, nervous system, bones, joints, and skeletal muscles also come under attack.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT the) (NN part)) (PP (IN of) (NP (NP (DT the) (JJ skeletal) (NN system)) (SBAR (WHNP (WDT that)) (S (VP (VBZ connects) (NP (NNS bones) (NNS joints))))))))) (. .)))