Nerve entrapment syndromes of the upper extremity are fairly common. There are more and more work-related cases being reported each year. Overhead throwing athletes are also affected.
There are many possible causes for the kind of pressure on the nerve that can cause painful symptoms, numbness, and weakness. The most common are from anatomical variations in the shape of the bones near the nerves. The location of the nerves as they pass through muscles can also be a factor.
Changes in the cervical spine (neck) can cause problems from nerve compression. Bone spurs, joint hypertrophy, and other arthritic changes can impinge nerves in the upper neck and arm causing ulnar nerve compression.
Tumors, cysts, and fibrous tendon or muscle bands can apply pressure directly to the nerve. Knife wounds, fracture, crush injuries, or other trauma can result in bleeding in and around the nerve. All of these problems can occur anywhere along the length of the nerve as it leaves the cervical spine and travels down to the hand.
The specific cause of ulnar nerve entrapment may be identified with further testing. X-rays, EMG studies, physical exam, and lab values all help point to the etiology (cause) and the location of the problem. Treatment is determined based on these findings.