( ( a ( concussion injury ) ) ( ( affecting ( the brain ) ) ; ) )
(ROOT (S (NP (DT a) (NN concussion) (NN injury)) (VP (VBG affecting) (NP (DT the) (NN brain))) (: ;)))
a concussion injury affecting the brain;
(ROOT (S (NP (DT A) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN concussion)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (NN type)) (PP (IN of) (NP (NN brain) (NN injury))))) (. .)))