Cryptotetany--place of EMG-recording

Ninety-two cryptotetany tests were performed with simultaneous EMG-recording in the M. Interosseus dorsalis I and the M. Opponens pollicis. It was found that, in 21 cases out of 92 (22.8%), exclusively in the M. Interosseus dorsalis I, and in 11 cases out of 92 (11.9%), exclusively in the M. Opponens pollicis, multiplet activity was detected for at least 2 minutes. From this study it appears that, in performing the cryptotetany test, the M. Opponens pollicis is certainly not be preferred to the M. Interosseus dorsalis as the only place of recording. It appears, on the contrary, that simultaneous recording in the M. Interosseus dorsalis I and the M. Opponens pollicis is to be preferred to a recording exclusively in the M. Interosseus dorsalis I. In this way, a not unsignificant number of false negative cryptotetany tests can be avoided.