From The Bodily Fisic, by Sartoris Mateme, an Arcaitian medical text that is the cornerstone of any physik doctor’s education.
A broken bone is easily mended by a wizard, yet the wound of a backbone can be delicate to set right again. If someone lives remotely and they happen to fall, not near any mage, woodland healer’s hut, or any people at all and they let it heal on it’s own without seeking any of those helpful folk at all, then the bones may regrow wrong or the injury so great to begin with that they will never walk again. Self-sufficient yeomen, calm in their humble farms, isolated, would not be able to work their fields and would starve if a parson or wizard does not come calling or if they do not crawl to the nearest neighbor. In County Dunn the folk there tell of a man Arthren, out on his farmstead, broke his leg, and drug himself 20 miles to the next farm, eating rabbits an squirrels along the way, cutting his hands and scraping along rocks and twigs for 3 days before his slowly lurching lump collapsed at the gate of a Yeoman Jonner. Barring this determination, if the break is left to heal on its own, crippled limbs are much harder for a wizard to heal. There is no wound to close, no raw flesh and swollen tissue to command back in its place, and it is hard to see with the glowing hand what is inside a leg. Some brute magicians take to chopping the leg off cleanly at the site of the break and fusing it back on as it’s supposed to be, but even that is an imprecise art. Those skilled in the unseen, attuned to the blind movements of surrounding nature, are the best at setting ill-healed bone breaks right, but the experiments of a mad, crude transmogrifier on living tissue have the most power to repair if they are performed right. It is a blear physic cursed for challenging hell. Therefore, the maintenance of healer at hand and thus immediate healing is the simple prevention for crippling. Now wounds of a magical nature are of an entirely different matter. There are many spells which can render a wound unwilling to heal and even those that will lacerate the wound further if healing is attempted. This is done by manner of a hex that intercepts the power of the healing spell and redirects it to its own foul purpose. A sensing of a magical wound first before treatment is necessary. Deep and dark magic make injuries far worse than the unhealed of material nature. Vile wizards have stricken their victims with such curses, but more often mages will halve and seal their enemies and leave them on the field to wait to be found and live out their lives half men of magical means. For too many dark lords this fate is more satisfying than the preventing the return of an enemy. As for those born with deformities, the situation is much like that of poorly healed injuries. Some a wizard can sense and correct, others may be too twisted and beyond their abilities. It would be a grave world we must live in to have to live permanently with every injury that befalls man.