A prior unadjudicated disability to the back, whether conspicuous to or occult from a human eye, does not constitute the employee a physically impaired person within the meaning of the statute, unless such disability affects a specific member of the body in a manner which makes the loss of use thereof, be it total or partial, obvious and apparent to an ordinary layman. 85 O.S. 1951 ยง 171[ 85-171]; Special Indemnity Fund v. Keel, 196 Okla. 315, 164 P.2d 996; Special Indemnity Fund of State of Okla. v. Iven, supra; Special Indemnity Fund v. Smith, Okla., 349 P.2d 759; Gullet v. State Industrial Commission, Okla., 346 P.2d 719; Special Indemnity Fund of State of Okla. v. Levering, Okla., 345 P.2d 885; Special Indemnity Fund v. Wade, 199 Okla. 547, 189 P.2d 609. The trial tribunal did not find that the pre-existing unadjudicated disability to the back produced an impairment of any specific member of the body and the record fails to disclose any evidence which would have justified such conclusion.