At the hearing, claimant did not appear preoccupied with personal discomfort and his thoughts did not wander during the hearing. He answered questions alertly and his general appearance suggested no obvious abnormality." In reviewing the record for substantial evidence, "issues of credibility and the drawing of permissible inference from evidentiary facts are the prime responsibility of the Secretary."

"Substantial evidence" is the standard of review by the District Court; issues of credibility and drawing of permissable inferences are for the Secretary.

Claimant's fully healed right knee fusion does not constitute a medically determinable cause of claimant's subjective complaints of disabling pain. Subjective complaints of pain must be considered and evaluated, but only if there is a medically determinable impairment that could cause the pain. Court noted that a diagnosis of psychological disorder that transforms emotions into pain is a sufficient basis for the finding of a medical or medically determinable impairment.