416.911—Definition of disabling impairment.
        
        (1) 
         A disabling impairment is an impairment (or combination of impairments) which, of itself, is so severe that it meets or equals a set of criteria in the Listing of Impairments in appendix 1 of subpart P of  part 404 of this chapter or which, when considered with your age, education and work experience, would result in a finding that you are disabled under  § 416.994, unless the disability redetermination rules in  § 416.987(b) apply to you.
    
    
        
        (2) 
         If the disability redetermination rules in  § 416.987 apply to you, a disabling impairment is an impairment or combination of impairments that meets the requirements in  §§ 416.920 (c) through (f).
    
    
        
        (b) 
         If you are a child, a disabling impairment is an impairment (or combination of impairments) that causes marked and severe functional limitations. This means that the impairment or combination of impairments: