I have to admit, these are the kind of stories I love. Going in I know next to nothing about the brachial plexus, which excites me. I get to learn something new and, hopefully, you do too. This is a story about Chris Carpenter, the oft injured St. Louis Cardinals pitcher. Carpenter is suffering from an injury of the brachial plexus, which inhibits his pitching. According to Dr. George Paletta:

No one first and foremost has been able to tell Chris, 'If we do nothing, you'll go two or three years without a problem.' No one's been able to say that. That's part of the difficulty in making a decision as to the best treatment option for the long term. Short term, it's simple.

Carpenter's condition has the doctor's stumped. So what exactly is the injury and how is it supposed to heal?

What is the brachial plexus? The brachial plexus is a bundle of nerves running from the neck down to the upper chest and arm. The primary responsibility of this bundle is to move your upper body including the arms. It's a critical nerve bundle for pitchers in baseball, as it controls the muscles in the arms. 

How is the brachial plexus injured? In most cases you can injure the nerve from a traumatic accident such as with a car or motorcycle. The nerve roots are pulled from their source and you develop lesions, which inhibit the nerve communication.The nerves can also be severed depending on the accident. In Carpenter's case they don't know why it's happening.

How do you treat an injured brachial plexus? Time. Peripheral nervous system nerves will grow back at the rate of 1/4 inch a week. This is with the understand that the cause of the issue is known and addressed. For instance, a person with a tumor pushing up against the brachial plexus will have the tumor removed and normal growth will occur. In Carpenter's case, they don't know or they're not saying what caused the issue. There are genetic conditions that can cause abnormal nerve development and regeneration.

Can you recover from an injured brachial plexus? Yes, you can, but possibly with diminished capacity. Surgical options exis with succes rates of up to 80%, but these were different circumstances.