c ) ( 3 ) . Thus , service connection may be granted for disability resulting from disease or injury incurred or aggravated while performing ACDUTRA , or from an injury incurred or aggravated while performing INACDUTRA . 38 U . S . C . A . § § 101 ( 24 ) , 106 . There are particular requirements for establishing PTSD in 38 C . F . R . § 3 . 304 ( f ) , which are separate from the general requirements for establishing service connection in 38 C . F . R . § 3 . 303 . See Arzio v . Shinseki , 602 F . 3 d 1343 , 1347 ( Fed . Cir . 2010 ) . Establishing service connection