920 cases with peripheral nerve injuries those who were seen in Hanyang University Hospital EMG laboratory during a period January 1972 -October 1983 were evaluated for the causes.

This study revealed that the causes were traumatic, occupational and pathological factors locally or systemically. And many of them could be prevented if a certain caution was made.

3 nerves of upper extremity and 2 nerves of lower extremity those nerves most frequently affected were evaluated and the causes were discussed.

In 204 median nerve injuries evaluated (Table 1-1), laceration and penetration injuries was most common cause(51.5%) and the next common cause was compression and traction injuries (33.8%). The later group(69 cases) was evaluated again for the details. As table 1-2 shown the carpal tunnel syndrome was most frequent cause(76.8%) and 5 other various causes were encountered.

In 219 ulnar nerve injuries evaluated(table 2-1), laceration was most frequent(46.6$) and the next frequent causes were compression and traction injury(15.1%). The later group (33 cases) was evaluated again for the details. As the table 2-2 shown simple compression at the elbow was in 60.6% and 4 other causes were encountered.

In 162 radial nerve injuries evaluated(table 3-1), fracture of the humerus was the most frequent(37.0%), and the next frequent cause were compression and traction injuries(19.8%). The later group(32 cases) was evaluated again for the details. As the table 3-2 shown simple compression at the humerus was in 62.5% and 5 other causes were encountered.

In 303 peroneal nerve injuries evaluated(table 4-1), compression & traction injury and IM injection the gluteal region were the 2 most frequent causes(16.8%, 16.8%). The former group(51 cases) was evaluated again for the details. As the table 4-2 shown compression at the fibular neck was in 54.9% and 6 other causes encountered.

In tibial nerve injuries evaluated(table 5-1), IM injection injury was the most frequent causes(25.0%) and compression injury was in 9.4%. The later group(3 cases) was evaluated again for the details. As the table 5-2 shown massive edema of leg with CO intoxication in 66.6% and the other was due to a prolonged cramp of calf.