Contraction properties of the superior pharyngeal constrictor muscle.
OBJECTIVE
The mechanical contraction property of the superior pharyngeal constrictor (PC) muscle was analyzed and compared with the levator veli palatini (LVP) muscle.


METHODS
Twenty adult dogs anesthetized with sodium pentobarbital were used.


RESULTS
The isometric contraction curves of LVP and PC were recorded after direct electric stimulation to each muscle. The contraction time of isometric twitch contraction of the superior PC muscles was 30.3+/-5.25 msec, and the half relaxation time was 22.97+/-5.44 msec. The summation curve was observed at a stimulus frequency above 20 Hz of a repetitive pulse stimulus frequency of 85 Hz.


CONCLUSIONS
The mechanical contraction properties of the PC muscle are similar to those of the LVP, but with more aspects that are characteristic of a fast twitch muscle.
Ishii
S
S
First Department of Oral and Maxillofacial Surgery, Osaka University Faculty of Dentistry, Suita City, Japan.
Kogo
M
M
Iida
S
S
Adachi
T
T
Hamaguchi
M
M
Matsuya
T
T
D000818:Animals; D004285:Dogs; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D007537:Isometric Contraction; D009119:Muscle Contraction; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D010156:Palatal Muscles / Q000502:physiology; D010609:Pharyngeal Muscles / Q000502:physiology*; D013997:Time Factors