Wheatley J R, Brancatisano A, Engel L A
Thoracic Medicine Unit, Westmead Hospital, Sydney, New South Wales, Australia.
J Appl Physiol (1985). 1991 May;70(5):2226-32. doi: 10.1152/jappl.1991.70.5.2226.
The role of the cricothyroid muscle (CT) in respiration is unclear. To examine the respiratory-related electrical activity of the CT, we measured its electromyogram (EMG) and compared it with that of the alae nasi (AN) in eight healthy subjects. During quiet breathing the CT EMG phasing was inspiratory in seven subjects. This pattern was similar to the AN with respect to phasing and shape of the integrated EMG. The onset of phasic CT and AN activity related to inspiration preceded flow by 173 +/- 39 and 570 +/- 76 (SE) ms, respectively (P less than 0.01). We measured the duration from onset of phasic activity to peak of the EMG (TA) and the total cycle duration (TT). TA/TT of the CT was 0.29 +/- 0.02, similar to that of the AN (0.28 +/- 0.03). Inspiratory resistive loading, panting, and voluntary hyperventilation increased CT activity above the peak level seen during tidal breathing. Voluntary glottic closure increased CT activity to a level above tonic but below peak tidal activity. The findings suggest that the phasic electrical activity of the CT simulates predominantly that of an upper airway dilator.
环甲肌（CT）在呼吸中的作用尚不清楚。为了检测CT与呼吸相关的电活动，我们测量了8名健康受试者的环甲肌肌电图（EMG），并将其与鼻翼肌（AN）的肌电图进行比较。在安静呼吸时，7名受试者的CT肌电图相位为吸气相。这种模式在积分肌电图的相位和形状方面与鼻翼肌相似。与吸气相关的CT和鼻翼肌的阶段性活动起始分别比气流提前173±39和570±76（SE）毫秒（P<0.01）。我们测量了从阶段性活动起始到肌电图峰值的持续时间（TA）和整个周期的持续时间（TT）。环甲肌的TA/TT为0.29±0.02，与鼻翼肌的TA/TT（0.28±0.03）相似。吸气阻力负荷、喘气和主动过度通气使环甲肌活动增加至高于潮式呼吸时所见的峰值水平。主动声门关闭使环甲肌活动增加至高于静息水平但低于潮式呼吸峰值活动的水平。这些发现表明，环甲肌的阶段性电活动主要模拟上呼吸道扩张肌的电活动。
