Good. Got a doctor yet? Hospital? If not, get on it D:<
Unfortunatley I lack a hospital, or anyplace to make a hospital, or anyone to work at the hospital, or the knowledge of how they work.
Sheesh, man, it's easy. Just dig out a room, stick a few beds and chests in it, and make sure you have splints, cloth, and thread available (in the next bug fix, casts and crutches will be fixed, so then, you'll need those to). Designate a hospital zone over this room and watch your dwarves fill up the chests with the necessary materials.
Now, go into the nobles screen and appoint a chief medical dwarf. The one at the top of the list is the dwarf in your fort with the highest skill in diagnosis (diagnosis is required before the patient is treated, even though it should be pretty obvious that he's got, say, an arrow lodged in his left testicle). Appoint him, or anyone else, really.
If all goes well, your wounded dwarves will go to rest in the hospital, get diagnosed, and then fixed up, which may have some delays if your chief medical dwarf has labors turned on besides all the ones in healthcare (hint).
Some dwarves will remain in the hospital for the rest of their lives in the current version - those with broken spines, for instance - but your expedition leader, for example, will be fine.
If you don't have any splints, they can be bought, or made in a carpenter's workshop. Thread and cloth should be obvious. Having a water source (a well) helps in preventing infection somewhat. Soap helps too, much more reliably, but seeing as soap is still bugged, you'd do well to avoid making it, 'cuz otherwise you'll be spammed with your dwarves canceling the clean self job (item inaccesible). If you do make soap for the hospital, dig a dwarven bathtub in an oft-frequented hallway - as your dwarves pass through it, they'll be cleaned, and they won't bother you about the soap.
The more you know.