( ( parts ( of ( the ( thyroid ( , ( ( parathyroid and ) thymus ) ) ) ) ) ) ( glands . ) )
(ROOT (S (NP (NP (NNS parts)) (PP (IN of) (NP (DT the) (NN thyroid) (, ,) (NN parathyroid) (CC and) (NNS thymus)))) (VP (VBZ glands)) (. .)))
parts of the thyroid, parathyroid and thymus glands.
(ROOT (S (NP (DT The) (CD two) (JJ parathyroid) (NNS glands)) (VP (VBP are) (VP (VBN located) (PP (IN behind) (NP (DT the) (NN thyroid) (NN gland))))) (. .)))