As bass players, we subject our hands to repetitive use of certain muscles and tendons in the arm, forearm, wrist and hand, often causing or worsening an existing injury that we may or may not know about. In the medical world, this is called Repetitive Stress Syndrome (RSS) or Repetitive Stress Injury (RSI) and includes conditions like carpal tunnel syndrome (CTS). Playing seems to rarely cause the problem, unless your technique is extremely poor. Playing will often make it worse, though, if you already have symptoms.
Before continuing on, I should point out that if you find yourself with sore wrists after playing, the inability to grasp and hold anything, that you are dropping things, or that you wake up at night because your hands have gone numb and you have to shake them out to make the numbness go away, you need to see a doctor. If one half (thumb, forefinger, half of middle finger OR half of middle finger, 4th finger and pinkie) of your hand is difficult to control, or numb, or has less feeling in the fingers than the other half, or the other hand, you need to see a doctor. Either see your regular doctor or go straight to an orthopedist (someone who specializes in the musculoskeletal system), even a clinic if that's all you can afford.
If you have these problems, and you see a doctor, tell your doctor you play. Some doctors DO play guitar and bass, and they can show you proper placement of your hands. If your doctor does not, then ask a teacher. One lesson for proper technique is not going to kill you, and may help you on the road to recovery without surgery. Good hand placement doesn't look as cool as the monkey-arm look, but, the monkey-arm boys will do the hurting.
Speaking of surgery, this is the last option with almost any doctor. If your problem is so bad that you need surgery, you've managed to really damage yourself. RSI is usually treated conservatively, with anti-inflammatory medications, physical therapy, splinting, changing of habits and resting the offending joint, until it either gets better or gets bad enough to warrant surgery. After surgery, you have the bad luck of conservative treatment all over again until you heal. Up to eight weeks, sometimes, during which, you will most likely not even be allowed to touch your bass. So don't touch it if you are in this position.
How can you avoid all this? It really comes down to technique, and keeping your playing from compounding any problem you may already have. Avoid, at all costs, the "Death-claw grip". Keep your thumb on the back of the neck, your elbow away from your side, your fingers relaxed and the bass at a comfortable height. Too low, and you're bending down and creating a claw with your fret hand. Too high and you create the claw by keeping your arm too close to your body. Stretch your hands, fingers and wrists before playing. Five minutes of stretching before playing now will save you up to a year of pain in the future. In my case, it took nearly a year to rid myself of ulnar nerve compression, and a complete relearning of bass playing habits. It was not fun, and it did not feel good, and having only two-and-a-half working fingers really put a damper on my playing.
As far as I know, there are no MDs on ActiveBass. Yet, there are a ton of threads detailing ailing hands, wrists and fingers. See a doctor! See a doctor! See a doctor!
If you have been so unfortunate that you have broken a finger, your hand, your wrist, your arm, or your elbow, follow your doctors recommendations. DON'T play while you are healing this. It's like picking a scab. It's not tough or cool, and it will suck later when that bone has not healed properly because you just HAD to play.
April Stevenson has been playing bass for almost seven years and, in her other reality, is a medical transcriptionist for an orthopedic clinic.