For this reason her claim may not be sustained under the unusual pathological result doctrine. Cf. Findon v. NickChevrolet, 204 Pa. Super. 99, 203 A.2d 238. Judgment affirmed.
We find no capricious disregard of competent evidence in the case at bar, indeed no other determination by the Board could have been sustained on this record. Where, as in the instant case, there is no accident in the ordinary lay understanding of the term, disability which occurs in the performance of claimant's usual duties is not compensable if it results from the aggravation of a pre-existing physical weakness: Mohler v. Cook, 205 Pa. Super. 232, 209 A.2d 7. And see Findon v. NickChevrolet, 204 Pa. Super. 99, 203 A.2d 238. Judgment affirmed.
There is another bar to claimant's recovery in the instant case. Where there is no accident in the ordinary lay understanding of the term, disability which occurs in the performance of claimant's usual duties is not compensable if it results from the aggravation of a pre-existing physical weakness: Findon v. Nick Chevrolet Co., 204 Pa. Super. 99, 203 A.2d 238. Dr. Richards testified that, in view of claimant's congenital spondylolisthesis, "there is certainly a pre-existing weakness in the lower back". In Williams v. NewBethlehem Burial Service, 167 Pa. Super. 364, 74 A.2d 677, claimant suffered from a congenital spondylolisthesis which rendered him more susceptible to injuries of the back.
197 Pa. Super. 648, 180 A.2d 272, and that the word "accident" is popularly defined as a sudden and unexpected event: Lacey v.Washburn Williams Co., 309 Pa. 574, 164 A. 724. However, the law is well settled that the factor which is unexpected may lie either in the circumstance causing the injury or in the nature of the injury itself: Good v. Pa. Department of Property andSupplies, 346 Pa. 151, 30 A.2d 434. Where an employe is performing his usual work but there occurs an unexpected and unusual pathological result, the accident resides in the extraordinary nature of the effect rather than in the cause: Gammaitoni v. Gasparini Excavating Co., 185 Pa. Super. 643, 139 A.2d 679. The foregoing principle applies only to disability of a normal healthy workman who has no physical weakness other than is common to all men: Rovere v. InterstateCemetery Co., 164 Pa. Super. 233, 63 A.2d 388. Such disability is not compensable if it results from the aggravation of a pre-existing physical weakness: Findon v. NickChevrolet, 204 Pa. Super. 99, 203 A.2d 238. Carlson v. Batts, 207 P.2d 1023 (Idaho); Carter v.International Detrola Corp., 43 N.W.2d 890 (Michigan); Youngv. Melrose Granite Co., 189 N.W. 426 (Minnesota); Hurd v. Hesse Hurt, 172 S.E. 289 (Virginia).
Essential to an award in this class of case is, however, a finding that the claimant was a normal healthy workman before the event. Findon v. Nick Chevrolet, 204 Pa. Super. 99, 203 A.2d 238 (1964); Scannella v. Salerno Importing Co., 2 Pa. Commw. 11, 275 A.2d 907 (1971). Therefore, the Board must consider whether the claimant's previous back injury was disqualifying.