Stripped to the naked question upon which a decision rests, this case resolves itself to this: Was Spencer's condition of which he complains caused by accident, as asserted by him, which occurred either on the 5th or 8th of April, or was it merely the result of an old injury aggravated by the cumulative effect of exertions while doing heavy work prior to April 9th, as found by the Industrial Commission? It is only accidental injuries that are compensable. To be compensable on this application, the finding must be that the accident referred to caused the injury or condition of which the applicant complains or aggravated a pre-existing condition. If the applicant's present condition was caused by a previous accident, the injury being aggravated by the cumulative effect of exertion while doing heavy work, it cannot be held to have been caused by an accident arising out of or in the course of employment with the state road commission. If there is substantial competent evidence to support the finding of the commission, we may not disturb it. If undisputed competent evidence leads to but one conclusion, that of an accidental injury while applicant was in the employ of the state road commission, then we may set aside the negative award of the commission. I am unable to concur in the result reached in the opinion of Mr. Justice MOFFAT on this question. The commission made findings which are fully set out in the prevailing opinion. It was found that the incident with respect to dumping the *Page 356 scraper and claimed as the accident causing the injury did occur on April 5th. The date is of no importance on the question of fixing liability if in fact the injury was caused by such an occurrence in the course of employment. It was necessary, however, for the commission to find further that the condition of which applicant complains was caused by such accident, or that it was the result of something else. The commission made a definite finding that the injury was caused in some other manner and at some other time than by the occurrence of April 5th. The date is significant for other reasons. Testimony with respect thereto bears on the credibility of the applicant and is important in determining whether or not an injury resulted from the claimed accident. In his application for compensation, filed April 18, 1932, and in his testimony at the first hearing, held May 16, 1932, the applicant definitely fixed the 5th day of April, 1932, as the day of the happening of the accident. At the last hearing, and after the decision of this court in 81 Utah 511,20 P.2d 618, an amended application was filed where the date was said to be the 8th of April, and the testimony elicited from and on behalf of applicant at the last hearing attempted to fix that date as the correct one. There is ample evidence in the record to support the finding of the commission that the occurrence referred to happened on the 5th rather than on the 8th of April. The commission found that applicant's condition consisting of an injury to the sacroiliac joint was not caused by any "accident or single occurrence," but that it was the result of an old injury of January, 1930, and "the accumulated effect of labor performed by applicant since the month of May 1931." Evidence of Spencer's previous injury while employed by Davis Howe Co. in January, 1930, the treatment and care given him because of such injury, and a settlement with him by the state fund on account of such injury, was before the commission on this hearing. The evidence respecting date of injury had a more subtle influence on the decision than that indicated in the prevailing *Page 357 opinion. If the accident happened on the 5th, then Spencer continued to work dumping the scraper for two or three days thereafter, notwithstanding his own physician testified that such could not be done, while, if he was not injured until the 8th, it must be he suffered pain from some other cause, since the evidence shows he suffered pain in his back for two or three days before such date. Dr. Kahn, in answer to the question, "What effect would that have on his ability to perform manual labor or bodily exertion of any kind?" said, "He could not do it." When attention was called to the testimony of Mr. Spencer to the effect that he had been injured on the 5th and continued working until the 9th, and the testimony of Dr. Kesler that Spencer had visited him on the evening of the 8th and had told him he was injured on the 5th, Dr. Kahn said, "I can't understand it, that is all." The credibility of Spencer had a large influence on the decision because of this further fact that the symptoms of a sacroiliac sprain are almost wholly subjective. Except in unusual cases, the X-ray will not reveal the truth or falsity of the claim of such an injury. There were no external evidences of an injury. The physician must depend on statements of the patient as to whether or not he suffers pain. Dr. Baldwin testified:
"Q. Was there in this any definite objective symptoms? A. None that I could find.
"Q. And by subjective symptoms that means the symptoms that you get from the patient's statements? A. That is all."
The members of the commission had to decide what evidence they would believe. They were in a much better position to judge the credibility of witnesses than we are. They had known Spencer for more than ten years, during which time they had dealt with him personally with respect to eight or nine different injuries. In view of all the facts and circumstances, particularly the medical evidence and the previous experience which the commission had had with the applicant, they decided they could not put full credence *Page 358 in Spencer's testimony respecting the cause of his present condition. I think the state of the record is not such as to require a finding that Spencer's condition was caused by accident while employed by the state road commission. The Industrial Commission did not act arbitrarily or capriciously nor ignore reasonable and undisputed evidence which required an affirmative finding. There was substantial credible evidence before the commission which supports the finding made that the applicant's present condition resulted from a previous accident and injury to the sacroiliac joint plus accmulated effect of exertion while working. To hold otherwise, it would be necessary to disregard certain of the testimony of the medical witnesses and the reasonable inferences deducible therefrom. When the evidentiary facts are such that reasonable men might draw either one of two conclusions as to the ultimate facts, the findings of the Industrial Commission are conclusive on the court. The order of the Industrial Commission denying compensation should be affirmed.