1989 年 13 巻 1 号 p. 95-98
Infraspinatus muscle atrophy is recognized in various shoulder diseases. It is especially most common in suprascapular nerve disorders. Post reported that cases with suprascapular nerve disorder had severe posterior shoulder pain, but with little or no infraspinatus muscle atrophy, and that measurement of the distal latency was the most useful method of diagnosis. We measured the distal latency of the suprascapular nerves in cases with posterior shoulder pain and infraspinatus muscle atrophy. Inalmost all of the cases, we measured the degree of supra and infraspinatus muscle atrophy by echography. There were 18 cases: 12 males: 6females: average age 31.9. Almost all of the young cases were athletes (baseball: volleyball: rugby: football etc). Only three cases had delayed distal latency. During the operation of one case, we found the suprascapular nerve was pressed by a ganglion on the basis of the scapular spine. Two other cases were treated conservatively. Other cases had slightly delayed in distal latency but had no laterality. The average distal latency: disordered side (supraspinatus 3.20 ± 0.39 msec: infraspinatus 3.79 ± 0.73 msec. ) normal side (supraspinatus 3.12 ± 0.30 msec: infraspinatus 3.69 ± 0.70 msec. ) We could not prove suprascapular nerve disorder in most cases by measuring distal latency. But the clinical features lead us to suspect suprascapular nerve disorder, therefore we must follow those cases up.