It means that you have had no significant knee injury in the past and that you have no evidence, whether by X-ray, MRI or physical examination, of arthritis or cartilage damage in the knee.

CNN: Will jogging hurt an obese person's joints?

While gouty arthritis is diagnosed by aspiration of joint fluid, distinguishing tendinitis versus a sprain versus a fracture requires a clinical examination and possibly an X-ray or magnetic resonance imaging.

CNN: Do I have gout or tendinitis?

An examination of the unique eyes of skate (ray fish) led to advances in combating blindness, the horseshoe crab was crucial in developing a test for bacterial contamination, and sea urchins helped in the development of test-tube fertilization.

CNN: Mars can wait. Oceans can't

But Ray Palmer, of the Forensic Science Service, insisted his own re-examination of the fibres "bolsters the initial findings", that fibres linked Hall to the scene.

BBC: Suffolk murder conviction appeal rejected