Effects of electrical stimulation of cricothyroid and
thyroarytenoid muscles on voice fundamental frequency.
Botulinum toxin injections into
thyroarytenoid muscle provide an effective treatment for adductor spasmodic dysphonia and voice changes post botulinum therapy can be measured by both voice handicap index and voice analysis.
Predominance of FOG and FG muscle fibers correspond to the data obtained in physiological studies of laryngeal muscles of primates, dogs and rabbits (Hall-Craggs, 1968; Hast, 1969), in which the
thyroarytenoid muscle was classified as fast.
They also help the student to experience approaching a high note with high air flow, and without hauling too much vocal weight (e.g., overactivation of the
thyroarytenoid muscle) into the note.
The lesion was removed en bloc, including the involved
thyroarytenoid muscle (figure 2).
The medial surfaces of the vocal folds can become parallel without pressing the vocal folds together if cricothyroid and
thyroarytenoid muscle activities are balanced.
Then a 25-gauge butterfly needle was used to endoscopically deliver 2.5 units of botulinum toxin into the belly of the left
thyroarytenoid muscle. Hemostasis was achieved with the placement of neurosurgical patties saturated with epinephrine 1:1,000 over the bleeding mucosa.
Lower range singing is marked by more
thyroarytenoid muscle (TA) activity and lower subglottic pressure, while higher range singing in female classical production and male falsetto involves a more active cricothyroid muscle (CT) and generally higher subglottic pressure.
The depth of injection should be such that the injection volume is deposited just lateral to the
thyroarytenoid muscle so that the presence of the injected material results in medialization of the arytenoid cartilage.
Five units of BTX-A (2.5 U/0.1 ml normal saline) were injected into each of two locations on each
thyroarytenoid muscle with a 25-gauge laryngeal injection needle at the time of direct laryngoscopy.
The second factor is the amount of tensile stress that can be generated in either the vocal ligament or the
thyroarytenoid muscle fibers that course in the anterior-posterior direction.
Findings on laryngeal EMG were essentially normal except for the detection of a few large-amplitude motor units within the left
thyroarytenoid muscle that were not consistent with a focal laryngeal mononeuropathy.
