A. Claims for workers' compensation shall be allowed only:
(1) when the worker has sustained an accidental injury arising out of and in the course of his employment;
(2) when the accident was reasonably incident to his employment; and
(3) when the disability is a natural and direct result of the accident.
B. In all cases where the employer or his insurance carrier deny that an alleged disability is a natural and direct result of the accident, the worker must establish that causal connection as a probability by expert testimony of a health care provider, as defined in Section 52-4-1 NMSA 1978, testifying within the area of his expertise.