In Part One of the Matt Garza analysis, we noted that he threw five pitches while mainly relying on his fastball/slider combination to put hitters away. In Part Two, we'll analyze the source of his radial nerve irritation, and what it means for his long-term health.

What the Hell is the Radial Nerve?

Matt Garza landed on the 15-day disabled list in early April due to "radial nerve irritation." As Chris Neault from Disabled List Informer said:

The radial nerve supplies sensory and motor information to the back of the hand, forearm, and triceps. Most commonly, the radial nerve becomes irritated as it passes through the forearm or lateral elbow, most notably in the area of the supinator muscle. This muscle turns the palm upwards, such as when a power curve is thrown. The nerve may also get irritated as it passes by the bony structures on the outside of the elbow.

There are two bones in your forearm: The Ulna and the Radius. When pitchers experience "hyperextension" of the elbow joint, or release pitches with a supinated grip, they slam the ulnar olecranon processes into their humeral olecranon fossa (soft tissue), causing inflammation of the hyaline cartilage. In turn, this causes the ulna bone to irreversibly lengthen, which results in loss of flexion about the elbow.

Sound like a lot to digest? It is! But, here's a fun tip - if you know any competitive pitchers, preferably one who threw 120+ innings in a year and had a supinated breaking ball, ask him to touch the palm of his throwing arm to the throwing arm shoulder. Many people will be unable to do this - try it yourself. If you aren't a pitcher (or haven't had a freak accident causing loss of flexion about the elbow), you should have no problem laying your hand (or at least your fingertips) on your shoulder.

You've probably heard of Ulnar Collateral Ligament replacement surgery, better known as Tommy John surgery. However, you've probably never heard of radial nerve irritation. It is far less common than ulnar nerve irritation, but it does happen to baseball pitchers, and it is often misdiagnosed. As Chris Neault said above, the radial nerve is often irritated as it passes through the forearm or the lateral elbow in the area of the supinator muscle. The supinator muscle does exactly what it sounds like - it turns the palm upwards (or thumbs up).

Take a good look at the picture of Matt Garza that I used for the introduction of this post. Now compare it to Greg Maddux below:

Here's Garza again for comparison:

Note the position of the hand, most notably the flexion of the wrist. Greg Maddux's palm is turned down, while Garza's is towards first base. Garza is experiencing early pronation, which is not good. This still reinforces my believe that Matt Garza throws a supinated slider (and probably curve ball), as pronating early is the best way to achieve maximum supination through release. Bad news, Rays fans - that "nasty curve" you see on TV? It's destroying his elbow.

When Matt Garza supinates hard through release, he is taxing the relatively small supinator muscle in addition to slamming his olecrenanon process into its fossa, and irritating his radial nerve.

A supinated release is not efficient. For proof, we only need to look at how a boxer throws a straight punch:

A boxer throws a straight jab palm down and uses his pronator teres to add force to the punch. Punches are not thrown palm up!

Over the weekend Part Three will be up, finally doing a video-based analysis of Matt Garza's pitching mechanics.