Path
     Period
     Id
     Period
     Cardinality
     0 - *
     Definition
     A time period defined by a start and end date and optionally time.
     Comment
     A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times").
Period is not used for a duration (a measure of elapsed time). See [Duration](datatypes.html#Duration).
    
    
    
     Constraint
     
      
      
      All FHIR elements must have a @value or children 
     
      
      
      If present, start SHALL have a lower value than end 
     
      
    
    
    
  
    
     Condition