Thus, the judge, in making the inquiry, must be careful - particularly in cases where mental disturbances or disorders have supervened - not to lose sight of the focus which the definition in sub-paragraph (a) calls for lest he falls into the erroneous reasoning process of allowing the consequences of a mental disturbance or disorder to govern, or even intrude into, a finding of "impairment or loss of a body function". If, for example, a person loses the use of his or her limbs as a consequence of injury to the spinal column and cord, that loss is a consequence of the long-term impairment of the function of the spinal process. If, on the other hand, a loss of use of the limbs occurs as an hysterical response to minor trauma, it is the "mental or ... behavioural disturbance or disorder" which is producing the impairment of body function and it is, accordingly, the severity of the mental disorder itself which must fall to be considered under sub-paragraph (c). Between the two extremes to which I have referred will, no doubt, be a range of differing circumstances; but if the body of evidence before the judge demonstrates that the consequences of a mental disturbance or disorder are themselves producing the impairment of body function complained of, it would be, as Crockett and Southwell, JJ. pointed out, "anomalous" to regard those consequences as falling to be considered under sub-paragraph (a) of the definition when clearly it is the severity of the disorder or disturbance itself which falls to be judged under sub-paragraph (c). Although the textual distinction between sub-paragraphs (a) and (c ) has been touched upon in other decisions since Humphries v. Poljak (see, for example, Turner v. Love and The Transport Accident Commission[8]) their Honours' statement of principle remains as a seminal statement of principle governing the interpretation of the sub-section and ought, in my view, to be followed.