In the case of
back pain, the anatomical findings would be things like structural problems and changes with the spine, discs, nerves, tissues ect...
Clinical presentation refers to typical physical signs or symptoms that are associate with a particular disease, pain, numbness, inability to walk, things like that.
So the statement can mean that after look at the damage or disease in this person's back, their symptoms (pain, whatever) is not as severe as it could be or should be.