For special work one needs special knowledge and an acquired faculty for making use of it.

What does a second year's student make of a small thoracic aneurysm?
He knows the anatomy of the chest; he begins to know the normal heart sounds and areas of dullness; but he cannot yet fit his various items of knowledge together.

Then comes the experienced physician and perhaps makes a complete diagnosis without any examination at all, merely from hearing the patient speak or cough.

He has the same facts as the student, but he has acquired the faculty of instantly connecting an abnormality of function with its correleated anatomical change.

It is a matter of experience.