A complex muscle fiber network in the cricothyroid muscle: a scanning electron microscopic study.
OBJECTIVE
To examine the three-dimensional ultrastructure of cricothyroid (CT) muscle fibers to elucidate their morphologic characteristics with regard to the specific functions of the muscle.


METHODS
An anatomic animal study.


METHODS
The CT muscles of five adult rats were processed using the HCl-hydrolysis method to remove the peri- and intramuscular connective tissue components. The fine muscle fiber arrangements were observed by scanning electron microscopy.


RESULTS
Complex muscle fiber interconnections (myomyous junctions) were identified in the muscles. Myomyous junctions were characterized by the connection of many villous processes that were 1 to 2 mum in diameter and 2 to 4 mum in length with a serrated appearance at the ends of a lateral branch or a bifurcating trunk of the muscle fibers.


CONCLUSIONS
Myomyous junctions form a complex muscle fiber network, which is thought to synchronize the activity of the CT muscle fibers. This is the first three-dimensional demonstration of the muscle fiber network in the CT muscle; this network may play a major role in the functional specificity of the CT muscle.
Hyodo
Masamitsu
M
Department of Otolaryngology, Ehime University School of Medicine, Toon City, Ehime, Japan. hyodoma@m.ehime-u.ac.jp
Taguchi
Aki
A
Yamagata
Takahiko
T
Desaki
Junzo
J
D000818:Animals; D003413:Cricoid Cartilage; D007821:Laryngeal Muscles / Q000033:anatomy & histology / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning / Q000295:instrumentation; D018485:Muscle Fibers, Skeletal / Q000648:ultrastructure*; D010699:Phonation / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013957:Thyroid Cartilage