quote:Originally posted by Gameth:
Impingment is when the muscle/tendons of the rotator cuff (usually the supraspinatus or infraspinatus are compressed between the greater tubercle of the humerus and the acromion. This happens normally at around 120 degrees of shoulder abduction. It can be a genetic condtion or overuse/poor mechanics. Like elbow higher then the shoulder during overhead throwing. It leads to a lot of pain and possible rupture of the tendons if not treated properly and the mechanism of injury fixed. It can become chronic in the form of tendonosis and usually is followed by a rupture in that case due to the build up of scar tissue in the tendon.
Ulnar nerve entrapment can happen at the thoracic outlet (TOS) where it can be compressed by the scalene muscles of the neck. At the elbow as it runs along the olecranon in its groove or under the pronator teres muscle. Ulnar nerve is your "funny bone". It can also be compressed at the wrist. Very similar to carpal tunnel syndrome but it affects the pinky and ring finger instead of the thumb/index/middle fingers. Those are the median nerve. Throwing can create traction to the ulnar nerve at the medial elbow.
Nicely done, Gameth. These are both solid explanations. You must have some medical knowledge if not background.
I would add that impingement is a theory and IMO has more to do with shoulders than elbows.
People aren't exactly sure what the precise cause of shoulder problems is, but the theory is that in certain orientations of the shoulder, muscles can rub against bones and be weakened that way. You can also put muscles and ligaments in mechanically problematic positions that can make them more vulnerable to injury.
In terms of elbows, IMO impingement is less of a problem at the beginning of an injury and more of a problem when the UCL starts to let go and the elbow joint starts to loosen up. In that case, too much stress can be placed on structures like the Ulnar Nerve as things in the elbow start to float around and get out of place due to the laxity of the joint.