ELECTROMYOGRAPHY OF THE PRIMARY ROTATORS OF THE FOREARM
- VernacularTitle:前臂主要迴旋肌的肌电
- Author:
Tianming CHANG
- Publication Type:Journal Article
- From:
Acta Anatomica Sinica
1955;0(03):-
- CountryChina
- Language:Chinese
-
Abstract:
The electromyographies were made on 12 healthy young adult males to investigate the function of supinators and pronators in the extended and flexed elbows during pro- nation and supination.The potentials were picked up with the needle electrode from the pronator teres,pronator quadratus,the supinator,the biceps brachialis and the bra- chioradialis.The study revealed the following facts: 1.During slow pronation,regardless whether the elbow was flexed or extended, the potentials from the pronator quadratus were always more active than that from the pronator teres.The former showed the activities from “marked” to “most marked” and the latter from “slight” to “moderate”.When the pronation was resisted,the activities increased in both muscles. 2.During slow supination,both pronators showed activities of various degree as antagonistic muscles.During slow supination in the extended elbow,the potentials ap- peared in the supinator alone,but no activities were seen in the biceps unless the supina- tion was resisted.The biceps was,therefore,not proved to be a supinator when the elbow was in an extending position.When the flexed elbow was supinated from a prone position,the activities were recorded from the supinator immediately but none from the biceps at first.When the forearm reached an intermediate position,it began to show “slight” activity whereas the supinator showed “marked”.When the forearm moved to- ward full supination the activities of the supinator decreased gradually,reaching “no activity” at the end,but the activities of the biceps increased gradually.It was proved that the supinator was a primary supinator and the biceps a reinforcer. 3.The brachioradialis is usually described as a pronator when the forearm is in supine position and a supinator in prone position.This present study showed it was neither a pronator nor a supinator in the extended forearm,and it was only so when supinating a flexed forearm from a prone to semiprone position.In the further course of supination the activities were not increased at all.Thus the brachioradialis could be considered as an axillary supinator from prone to semiprone position.
