Lip Muscles Research Articles

Extracranial head and neck cysticercosis: report of nine cases with emphasis in serologic analysis and natural history of the disease

Cysticercus cellulosae is the larval form of Taenia solium, representing the second most common larval infection in humans produced by cestodes. It affects any tissue but is more common in skeletal muscle, CNS and eye. This infection has been known since 500 BC; in Guatemala it was first reported in 1877. It has no racial predilection but is rare in Jews and Moslems who do not eat pork. Humans are definitive hosts for Taenia solium ; pigs and wild hogs are intermediate hosts, but humans can manifest the sporadic larval form. Human cysticercosis is acquired by ingestion of infected pork or fecally contaminated foods. Cysticercosis is clinically characterized by the presence of solitary or multiple submucosal/cutaneous firm nodules, which are circumscribed, movable, usually asymptomatic, and measure 1-1.5 cms. Mature cysticerci are small translucent oval cysts containing the invaginated scolex with 4 sucking openings, each with a double crown of hooks. Macroscopic and microscopic features are both diagnostic. Living larvae with an intact membrane do not elicit an inflammatory reaction unless degenerated or dead. Anticysticercus serum titers are valuable for follow-up and should be first determined before or immediately after diagnosis. MRI and/or CT are mandatory to rule out CNS involvement. The affected head and neck sites in our series are buccal mucosa (3), lower lip (2), upper lip (1), tongue (2), and temporal muscle (1). All of our cases represented single lesions, 3 of them without active CNS compromise. Systemic treatment is mostly recommended for CNS cysticercosis, Praziquantel being the most accepted drug.

Clinical and imaging diagnoses of intramuscular hemangiomas: the wattle sign and case reports

emangiomas are considered benign vascular rowths, that may have a congenital origin with the ossibility that trauma serves as a stimulus.1-5 They onsist of vessels that have a purposeless arrangement nd lack of functional relationship to the surrounding egion’s blood supply. These hemangiomas can occur hroughout the body, with 1% of them arising in the keletal muscle of adults.6-9 Intramuscular hemangioas (IMHs) most frequently involve the pelvic region, ut 10% to 15% occur in the head and neck reion,8,10,11 with the masseter muscle being the most ommon site.1,7,8,10,12 Approximately 36% of all head nd neck IMHs involve the masseter muscle.5 Lesions n the immediate circumoral region are rarely noted, lthough involvement of the lip musculature,8,13 the entalis muscle,14 and buccinator muscle8,15 have een reported. Two cases of IMH in the orofacial region are reported; oth showed the wattle sign, an enlargement of the linical vascular swelling when the head is in a depenent position. In the first patient, an extraoral swelling n the mandibular bicuspid region with phleboliths was resent. A second patient had a swelling that involved

The Importance of Maxillary Canine: A Review

Canines are the unique members of dental arches. They play a very important role in human and animal’s dentition. They support lip and facial muscles and in this way promote facial esthetics. In addition, the canines act as important guideposts in occlusion. Their deep overbite serves as a protective mechanism relieving the posterior teeth from excessive and potentially damaging horizontal forces during lateral excursion of the mandible. The ectopic eruption and impaction of the canine is a frequently encountered problem. The prevalence is estimated to be between 0.8 to 2.8% in the maxilla. In the maxilla, it is shown to be palatal to dental arch in about 85% of the cases. The etiology of the ectopic eruption and impaction is not well understood although, according to some speculations, it can have a multi- factorial feature as: arch length discrepancy, genetic and familial trend, delayed exfoliation of the primary canine, abnormal tooth bud’s position, trauma, etc. The diagnosis of unerupted canines involves: inspection, palpation and radiographic assessment. The ectopic canine would often require complex multidisciplinary treatment involving surgical, restorative, periodontal as well as orthodontic components. In this article, an overview of the incidence and sequelae as well as the surgical periodontal and orthodontic considerations in the management of impacted canines are presented. Key words: Maxillary canine- Diagnosis of Impaction- Treatment

Activity of lip muscles associated with simulated upper incisors position

Activity of lip muscles associated with simulated upper incisors position

5. 上顎前歯の前後的位置と口唇閉鎖機能における口唇の筋活動との関係(11月例会講演抄録)

5. 上顎前歯の前後的位置と口唇閉鎖機能における口唇の筋活動との関係(11月例会講演抄録)

Electromyographic activity of the lip muscle as a measure of puffing on a cigarette

The electromyographic activity (EMG) of the upper lip muscle (m. orbicularis oris) during sucking on a cigarette was examined as a potential new measure of smoking behaviour. This parameter was examined under conditions of actual smoking, sham smoking and sucking on a straw. We applied psychophysical procedures (methods of magnitude production), normal and paced smoking, two conventional means to confirm puffing (video recording and changes in air pressure in a cigarette holder) on different groups of smokers (heavy and light). The data revealed that lip-EMG is a valid and reliable means to quantify sucking on a cigarette in a variety of situations common to the study of smoking. It was concluded that lip-EMG may be a sensitive and selective measure of motor activity associated with smoking. The lip-EMG may also be applied together with hand activity and breathing to identify individual puffing, particularly in heavy smokers and during actual smoking. Discussed were several applications of this method to the study of smoking and other motivated behaviour such as consumption of water and palatable fluids.

Lower lip repair in Van der Woude syndrome.

Van der Woude syndrome is an unusual congenital malformation. It combines lower lip sinuses with a cleft lip and/or palate. The asymmetry appears more pronounced due to lower lip hypotonia and procheilia, which are more unaesthetic than the fistulae themselves. The malformation of the orbicularis oris muscle in its medial part induces the hypotonic aspect of the lower lip, which contrasts with the retracted scarred upper lip after the cleft has been repaired. It is also responsible for a real bilabial asymmetry. For many years, the most common surgical treatment was simple excision of the sinuses. Bad functional repair results prompted the authors to try another surgical procedure, the split-lip advancement technique as described by Mutaf. The authors report here on 8 operated children out of 25 patients followed up for Van der Woude syndrome. They evaluated the results according to the appearance of the lip when relaxed, its functional aspect, and the satisfaction of the parents or the child. Our results point to the importance of early surgical treatment, radical excision of dysplastic tissue and the repair of lip muscles to restore good lip functionality and satisfactory bilabial symmetry. The technique now used in our department has made it possible for us to achieve these goals.

Typical Versus Atypical Oral Motor Function in the Pediatric Population: Beyond the Checklist

Typical Versus Atypical Oral Motor Function in the Pediatric Population: Beyond the Checklist

Seeing and hearing speech excites the motor system involved in speech production

The perception of action is associated with increased activity in motor regions, implicating such regions in the recognition, understanding and imitation of actions. We examined the possibility that perception of speech, both auditory and visual, would also result in changes in the excitability of the motor system underlying speech production. Transcranial magnetic stimulation was applied to the face area of primary motor cortex to elicit motor-evoked potentials in the lip muscles. The size of the motor-evoked potentials was compared under the following conditions: listening to speech, listening to non-verbal sounds, viewing speech-related lip movements, and viewing eye and brow movements. Compared to control conditions, listening to and viewing speech enhanced the size of the motor-evoked potential. This effect was only seen in response to stimulation of the left hemisphere; stimulation of the right hemisphere produced no changes in motor-evoked potentials in any of the conditions. In a control experiment, the size of the motor-evoked potentials elicited in the muscles of the right hand did not differ among conditions, suggesting that speech-related changes in excitability are specific to the lip muscles. These results provide evidence that both auditory and visual speech perception facilitate the excitability of the motor system involved in speech production.

Electromyographic activity of lower lip muscles during chewing with the lips in contact and apart

Electromyographic activity of lower lip muscles during chewing with the lips in contact and apart

Movement-related modulation of vibrotactile detection thresholds in the human orofacial system.

By virtue of the direct coupling between circumoral skin and the underlying orofacial musculature, mechanosensation associated with precise orofacial force control may contribute significantly to processes associated with perception, proprioception, and sensorimotor control in this region. The purpose of this study was to assess lower lip (LL) vibratory detection thresholds of adult subjects during the simultaneous performance of a visually guided and continuous lip motor control task. Vibrotactile inputs were delivered to the right LL vermilion at test frequencies of 5, 10, 50, 150, 250, and 300 Hz. The psychophysical detection task was performed simultaneously with the three force control conditions: a null-force baseline condition, an active force control task performed with the right index finger, and an active force control task performed with the lip musculature. For the active tasks, subjects were instructed to use their analog force signal (lip or finger) to continuously perform a visually guided precision force task by tracking a 2 Hz sinusoidally moving target calibrated to a peak-to-peak force load of 0.2 N. Both the analog force signal and the target-tracking signal were displayed in real-time on an oscilloscope. Results showed a statistically significant elevation of LL vibrotactile detection thresholds for test frequencies below 50 Hz during the simultaneous performance of the lip force control task. Disassociating the site of motor control from the location of sensory stimulation (active control task) was effective in normalizing the elevations in LL vibrotactile thresholds, thus demonstrating that the threshold elevation during the lip force task was not solely an artifact of the added attentional load resulting from combining a perceptual task with a motor control requirement. These findings are discussed in relation to published reports of movement-related sensory gating in limb systems and the possible significance that this phenomenon may have for perception and proprioception in the orofacial system.

Histopathology of Cleft Lip Muscle: an Enzyme Histochemical and Electron Microscopic Study

Objective: This study was performed to identify the histopathological changes in the cleft lip muscle and its possible relationship to the pathogenesis of clefting.Patients and Methods: Biopsies of orbicularis oris muscle were obtained from the lateral cleft edge of 40 infants with unilateral complete cleft lip with or without cleft palate. Control samples were obtained from 13 infants who had accidental trauma to the lip. Frozen sections 8 μm thick were cut and stained with haematoxylin and eosin and examined for succinate dehydrogenase, nicotinamide adenine dinucleotide, and adenosine triphosphatase at pH 9.4, 4.2, and 4.6. The rest of the biopsy was used for electron microscopic studies.Results: There was a reduction in the number of muscle fibres with a relative increase in connective tissue in cleft lip muscle. There was a generalised reduction in the diameter of both type 1 and type 2 fibres and the quantity of type 2 fibres was increased. The cleft muscle showed increased oxidative enzyme activity and centrally located conglomerates of formazan deposits. Electron microscopic studies showed mitochondrial aggregates and morphological alterations. Other ultrastructural features of the cleft lip muscle were comparable with those of the control samples.Conclusion: These results show that cleft lip muscle is intrinsically different from healthy control muscle. The changes observed in cleft lip muscle are comparable with changes seen in developing muscle that is exposed to hypoxia. The role of hypoxia as a possible pathogenic factor that acts on the developing primary palate region during the critical period of development is discussed.

Developmental change in variability of lip muscle activity during speech.

Compared to adults, children's speech production measures sometimes show higher trial-to-trial variability in both kinematic and acoustic analyses. A reasonable hypothesis is that this variability reflects variations in neural drive to muscles as the developing system explores different solutions to achieving vocal tract goals. We investigated that hypothesis in the present study by analyzing EMG waveforms produced across repetitions of a phrase spoken by 7-year-olds, 12-year-olds, and young adults. The EMG waveforms recorded via surface electrodes at upper lip sites were clearly modulated in a consistent manner corresponding to lip closure for the bilabial consonants in the utterance. Thus we were able to analyze the amplitude envelope of the rectified EMG with a phrase-level variability index previously used with kinematic data. Both the 7- and 12-year-old children were significantly more variable on repeated productions than the young adults. These results support the idea that children are using varying combinations of muscle activity to achieve phonetic goals. Even at age 12 years, these children were not adult-like in their performance. These and earlier kinematic studies of the oral motor system suggest that children retain their flexibility, employing more degrees of freedom than adults, to dynamically control lip aperture during speech. This strategy is adaptive given the many neurophysiological and biomechanical changes that occur during the transition from adolescence to adulthood.

Physiological effects of an 8-week mechanically aided resistance facial exercise program

This paper describes a study that for the first time addresses the physiological effects of an 8-week mechanically aided facial exercise program, using the Facial-Flex device (Facial Concepts, Inc., Blue Bell, PA) with four healthy individuals with no motor, speech, language, or hearing problems. For a variety of non-speech and speech tasks, upper and lower lip muscle activity (EMG) and upper and lower lip movements were recorded at two baseline sessions (separated by 1 week) and immediately after an 8-week training period. The results indicate that after the training period, all four subjects showed an increase in the number of task repetitions and the duration of isometric contraction using the Facial-Flex device with a fixed resistance (Linebaugh tests). However, with respect to physiological changes as related to the exercise program, the results were mixed. Only one subject showed the expected significant increase in normalized EMG activity. This response was mirrored in a significant overall increase in movement range and peak velocity after the 8-week training period. Regarding the other three subjects, one subject showed no systematic training effect at all, whereas the remaining two subjects showed a significant increase in movement duration. Non-speech and speech tasks were found to be clearly different in their overall physiological characteristics; speech related movements were found to be more clearly defined in terms of larger amplitudes, shorter durations, higher peak velocities, and less variable movement cycles. The apparent discrepancy between the results of the Linebaugh tests and the physiological measures on specific oromotor tasks warrants some caution in drawing conclusions on changes in the oro-motor system based on general performance measures. Further studies with well-defined clinical populations are needed to assess the usefulness of this device as an aid in the treatment of speech disorders based on motor system impairments.

6. Electromyographic activity of lower lip muscles during chewing with the lips in contact and apart(12 月例会, 九州歯科学会月例会報告)(タイトルのみ掲載)

6. Electromyographic activity of lower lip muscles during chewing with the lips in contact and apart(12 月例会, 九州歯科学会月例会報告)(タイトルのみ掲載)

Histologic, histochemical, and ultrastructural analysis of soft tissues from cleft and normal lips.

The cause of cleft lip remains speculative. The nature and extent of pathophysiologic changes in cleft lip muscle are controversial. This study was undertaken to better understand the developmental processes at work. There were two groups of patients. In group 1, 40 fresh tissue specimens were taken from 22 patients who were 2 to 5 months old-their age at the time of their primary cleft lip repair. In group 2, eight control specimens were collected from six children who were seen in the emergency department with lip lacerations. Fresh specimens fixed in neutral buffered formalin were evaluated by the use of hematoxylin and eosin with Luxol fast blue, Bielschowsky, and Masson trichrome stains. Fresh frozen tissue was histochemically assessed by the use of hematoxylin and eosin, modified Gomori trichrome, and adenosine triphosphatase. Ultrastructural analysis was performed on fine sections of glutaraldehyde-fixed tissue. Histologic examination revealed increased endomysial and perimysial collagen in cleft specimens with evidence of muscle-bundle size variation and nonneurogenic atrophy. Insignificant differences were observed between cleft-side and noncleft-side specimens when the means of 200 counts of neural-tissue bundles in the subdermis were compared (p = 0.093). Histochemical examination revealed no typical checkerboard pattern, but a preponderance of type 2 fiber was seen. By means of electron microscopy, increased numbers of subsarcolemmal mitochondria were found in cleft, noncleft, and control specimens. Increased absolute numbers of mitochondria and variations in size, shape, and crystal arrangement were identified. In conclusion, there is no evidence of deficient neural supply in the cleft lip. There is also no evidence of neurogenic muscle atrophy or a metabolic abnormality. There are characteristic myopathic changes. These, in concert with the observed interstitial fibrosis, may have far-reaching implications for growth and function.

Word Length Effects on EMG/Vowel Duration Relationships in Apraxic Speakers

The effects of word length on the timing of lip electromyographic (EMG) activity for production of the vowel /u/ and the relationship of this activity to vowel duration were examined in matched male and female pairs of normal and apraxic speakers. Both apraxic speakers had suffered left cerebrovascular accidents, which resulted in apraxia of speech as the primary communication deficit. For all participants, the interval of time in which lip muscle activity was present prior to the onset of voicing for the /u/ (EMG onset interval) in each word systematically decreased as word length increased. However, EMG activity offset intervals, which were measured from the onset of voicing for /u/ to the onset of the reduction of EMG activity during the vowel (EMG termination interval), decreased as word length increased only for the normal speakers. Relative onset of EMG activity was not significantly related to relative offset of EMG activity or relative vowel duration. However, the relative EMG onset interval was correlated with the duration of an entire word. Findings for the relative EMG termination interval were variable and are discussed relative to the severity of apraxia of speech.

Lip muscle activity related to speech rate and loudness.

Changes in suprasegmental speech parameters may require adjustments in oral motor control that are reflected in the activity of perioral musculature. In order to evaluate possible patterns of difference, perioral surface electromyographic (EMG) signals were obtained from 20 adults who read a paragraph aloud at habitual rate and at self-judged proportionately slower and faster rates, at habitual loudness and at proportionately softer and louder levels, and in a "precise" manner. EMG amplitude analysis showed significant task effects, with higher average amplitudes for fast, loud, and precise speech and lower average amplitudes for slow and soft speech. These results are compatible with a model of multidimensional reorganization of speech motor control for suprasegmental changes applied to connected speech.

Pressure from the lips on the teeth during speech.

Pressure on the teeth from the labial soft tissues during the articulation of a given sentence was measured in 24 children, 8 to 14 years old, with normal incisor relationships. The points of measurement were labial in the midlines between the maxillary and mandibular central incisors and between the right maxillary canine and first premolar (the modiolus point). A mouthpiece was attached to the teeth at these three positions and connected via a water-filled system to an extraoral pressure transducer. A microphone recorded the volume and speed of articulation while the activity of the lip muscles was surveyed by electromyography. The maximal pressure during pronunciation of the consonant /p/, the pressure at rest (RP), the speech posture pressure (SPP), the time pressure integral (TPI), and the mean speech pressure (MSP) during articulation were analyzed. Maximal pressure during pronunciation of /p/ and TPI were highest at the modiolus, second highest at the lower midline, and lowest at the upper midline. RP and SPP were highest at the lower midline. SPP was 2 to 3 times higher than RP, and MSP was 4 to 7 times higher than RP. The pressures during articulation recorded at the lower midline were closely correlated with those at the modiolus, with weaker correlations between the upper and lower midlines and between the upper midline and modiolus. There was a close correlation between RP and SPP. SPP, MSP, and TPI may, along with RP, contribute to the positions of the teeth.

Effects of a myofunctional appliance on orofacial muscle activity and structures.

The aim of the study was to examine the effect of an oral shield treatment on orofacial muscle activity and facial morphology in children with lip and/or tongue dysfunction. The sample consisted of 7 girls and 2 boys, 7 to 12 years old. EMG recordings with and without the shield in situ were obtained when the shield was placed, and 3, 6, and 12 months later. Lateral cephalograms were obtained at the initial and 1-year stages. The lip muscles showed dominant activity when the subjects were sucking on an empty straw and during swallowing; this was strongest during the first 3 months. The mentalis, buccinator, and digastric muscles generally showed weaker activity. The anterior temporal muscle showed dominant activity during maximal clench, but after the 3-month stage a significant decrease was noted. After 1 year of treatment, no significant changes in overjet or overbite were observed. Most of the craniofacial growth changes were normal for the age group. The results indicate that treatment with an oral shield caused a decrease in orofacial muscle activity during oral functions. Although there was a slight average retraction of the maxillary incisors, the change in position was not statistically significant.