Chonnam Med J.  1995 Jun;31(1):91-102.

Reflex actions of the semicircular canals on the clavotrapezius muscle in cats

• Cho SJ
• Park SH
• Jeong HS
• Kim JH

Abstract

The present experiment was designed to observe action of the clavotrapezius muscle, a superficial cervical extensor, on the head in cats. The clavotrapezius muscles were subjected to direct electrial stimulation to produce contraction, and the head movements induced by the contraction were observed photographically. In addition, the semicircular canal nerves were electrically stimulated and the responses of the clacytrapezius muscle were recorded by means of electromyography. 1) Contraction of the unilateral clavotrapezius muscle evoked dorsal extension associated with the ipsilateral rotation of the head. 2) Simultaneous contraction of the bilateral clavotrapezius evoked pure dorsal extension of the head. 3) Stimulation of the horizontal canal nerve evoked the contraction of the contralateral clavotrapezius muscle and relaxation of the ipsilateral one. 4) The vertical canal nerve stimulation evoked the contraction of the contralateral clavotrapezius muscle and relaxation of the ipsilateral one. 5) Superimposed stimulation of the two paired canal nerves always produced the proper reflex action of the each canal on the clavotrapezius muscle. These experimental results indicate that the clavotrapezius muscle has not only extensor but also rotator actions on the head movements, as the other deep cervical extensor muscles, in cats

MeSH Terms

Animals
Cats*
Electromyography
Head
Head Movements
Muscles
Reflex*
Relaxation
Semicircular Canals*