Dilator Naris Function A Useful Test of Facial Nerve Clarence T. Sasaki, MD,
Douglas
G. Mann
\s=b\ The
dilator naris muscle is an active of respiration in man. Its level of function appears to vary directly with ventilatory resistance. Three cases are reported to illustrate the use of the respiratory function of this muscle as a clinical test of seventh nerve integrity when its volitional function cannot be elicited.
participant
(Arch Otolaryngol 102:365-367, 1976) functions have been ascribed muscle (DNM) of alae nasi. Some believe that the alar muscle plays a role in regulating the nasal valve, acting therefore as an effector of respiratory resistance.1-4 Others consider it to be merely vestigial in man, perhaps functioning purely in facial expression.1 Although it appears that its purpose in man has yet to be firmly established, it is more probable that the DNM functions alternately on two levels. It may be used volitionally in facial expression or it may contract rhythmically with respiration. This respiratory activity may be most easily appreciated in the dyspneic infant, but it may also be seen in the adult patient as well. The DNM respiratory function is for the most part
Many
to the dilator naris
Accepted
Integrity
publication Feb 26, 1976. Department of Surgery, Section of Otolaryngology, Yale University School of Medicine, New Haven, Conn. Reprint requests to the Department of Surgery, Section of Otolaryngology, Yale University School of Medicine, 333 Cedar St, New Haven, CT 06510 (Dr Sasaki).
involuntary and is regulated reflexly by the respiratory center.5-7 The effer-
facial nerve integrity when volitional function cannot be elicited.
the DNM and other facial muscles. The afferent limb of this reflex is less clear, but appears to be the thoracic vagus nerve, transmitting afferent impulses from pulmonary pressure and mechano-receptors to brain stem
Ten normal adult volunteers participated in this study. Electromyograms (EMG) of the DNM were obtained by inserting a bipolar concentric needle electrode into the alae nasi. Without anesthesia, this procedure did not prove excessively painful. Signals from this electrode were amplified by a preamplifier and were displayed on a polygraph. The EMG signals were simultaneously integrated and displayed in phase. Ventilatory pressure changes were monitored by a water-filled
ent limb of this reflex is the facial nerve, supplying motor innervation to
inspiratory
neurons.8
Our purpose is twofold: (1) to establish DNM as an active organ of respiration in man and (2) to use its respiratory function as a clinical test of
METHODS
B
for
From the
1.\p=m-\Relaxedbreathing muscle.
Fig
through
nose.
Downloaded From: http://archotol.jamanetwork.com/ by a New York University User on 06/06/2015
A, Integrated EMG. B, EMG of dilator naris
tube inserted into the airway. From a transducer, pressure changes were ampli¬ fied by a preamplifier and displayed in phase oscillographically. In sequence, each patient was asked to breathe through the nose, breathe through the mouth, and breathe through pursed lips (simulating dyspnea). Proper electrode position was repeatedly checked by eliciting a voluntary nasal flare.
RESULTS
During eupneic nasal breathing, eight of ten patients demonstrated phasic inspiratory DNM activity, even though alar motion was not percep¬ tible with quiet respiration (Fig 1, Table). When subjects breathed through open mouths, only one of ten patients showed inspiratory DNM activity. Mouth breathing offered less ventila¬ tory resistance than nose breathing (Fig 2, Table). During respiration through pursed lips, all ten patients developed phasic DNM activity and visible alar flaring (Fig 3, Table). Duration of DNM discharge increased as did spike amplitude and frequency with in¬ creasing ventilatory resistance.
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Douglas
G. Mann
\s=b\ The
dilator naris muscle is an active of respiration in man. Its level of function appears to vary directly with ventilatory resistance. Three cases are reported to illustrate the use of the respiratory function of this muscle as a clinical test of seventh nerve integrity when its volitional function cannot be elicited.
participant
(Arch Otolaryngol 102:365-367, 1976) functions have been ascribed muscle (DNM) of alae nasi. Some believe that the alar muscle plays a role in regulating the nasal valve, acting therefore as an effector of respiratory resistance.1-4 Others consider it to be merely vestigial in man, perhaps functioning purely in facial expression.1 Although it appears that its purpose in man has yet to be firmly established, it is more probable that the DNM functions alternately on two levels. It may be used volitionally in facial expression or it may contract rhythmically with respiration. This respiratory activity may be most easily appreciated in the dyspneic infant, but it may also be seen in the adult patient as well. The DNM respiratory function is for the most part
Many
to the dilator naris
Accepted
Integrity
publication Feb 26, 1976. Department of Surgery, Section of Otolaryngology, Yale University School of Medicine, New Haven, Conn. Reprint requests to the Department of Surgery, Section of Otolaryngology, Yale University School of Medicine, 333 Cedar St, New Haven, CT 06510 (Dr Sasaki).
involuntary and is regulated reflexly by the respiratory center.5-7 The effer-
facial nerve integrity when volitional function cannot be elicited.
the DNM and other facial muscles. The afferent limb of this reflex is less clear, but appears to be the thoracic vagus nerve, transmitting afferent impulses from pulmonary pressure and mechano-receptors to brain stem
Ten normal adult volunteers participated in this study. Electromyograms (EMG) of the DNM were obtained by inserting a bipolar concentric needle electrode into the alae nasi. Without anesthesia, this procedure did not prove excessively painful. Signals from this electrode were amplified by a preamplifier and were displayed on a polygraph. The EMG signals were simultaneously integrated and displayed in phase. Ventilatory pressure changes were monitored by a water-filled
ent limb of this reflex is the facial nerve, supplying motor innervation to
inspiratory
neurons.8
Our purpose is twofold: (1) to establish DNM as an active organ of respiration in man and (2) to use its respiratory function as a clinical test of
METHODS
B
for
From the
1.\p=m-\Relaxedbreathing muscle.
Fig
through
nose.
Downloaded From: http://archotol.jamanetwork.com/ by a New York University User on 06/06/2015
A, Integrated EMG. B, EMG of dilator naris
tube inserted into the airway. From a transducer, pressure changes were ampli¬ fied by a preamplifier and displayed in phase oscillographically. In sequence, each patient was asked to breathe through the nose, breathe through the mouth, and breathe through pursed lips (simulating dyspnea). Proper electrode position was repeatedly checked by eliciting a voluntary nasal flare.
RESULTS
During eupneic nasal breathing, eight of ten patients demonstrated phasic inspiratory DNM activity, even though alar motion was not percep¬ tible with quiet respiration (Fig 1, Table). When subjects breathed through open mouths, only one of ten patients showed inspiratory DNM activity. Mouth breathing offered less ventila¬ tory resistance than nose breathing (Fig 2, Table). During respiration through pursed lips, all ten patients developed phasic DNM activity and visible alar flaring (Fig 3, Table). Duration of DNM discharge increased as did spike amplitude and frequency with in¬ creasing ventilatory resistance.
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