From my understanding:
1) You have a hole in the articular cartilage (shiny stuff like on a chicken bone) on the medial (inside) femoral condyle (knobbly bit at bottom of thigh bone) - c.1cm2, not big, not small but certainly could be painful if on the weightbearing surface (I have similar but on the outside, can be painful). This could be through to the bone, just says deep. Have you had a trauma?
2) trochlea - is the groove the kneecap sits in - suggests more diffuse softening
3) damage to the cartilage on the kneecap - softening again - 2) and 3) perhaps because you aren't tracking properly and the bones are rubbing together. Do you have a history of heavy impact sport etc?
These links will help with questions to ask the docs
http://www.kneeguru.co.uk/KNEEnotes/node/737 (anatomy)
http://www.kneeguru.co.uk/KNEEnotes/node/2263 (all about arthritis and cartilage etc)
Good luck
