Section II. Anatomy and Physiology

WILMA MAUE-DICKSON, Ph.D. (CHAIRMAN)

Introduction Middle Musculature, The Auditory Tube, and The Velopharyngeal This Section has been prepared for the Mechanism purpose of updating the previous report, "Status of Research in Cleft Palate: Anat- 1. Tur Mippour® Ear omy and Physiology," published in two parts in the Cleft Palate Journal, Volume 11, The authors of the previous report 1974, and Volume 12, 1975. questioned the validity of the concept that As indicated in the previous two-part the tensor tympani and the stapedius mus- report, it is imperative to consider not only cles provide protection to the inner ear the palate but all of the oral-facial-pharyn- from loud sounds, except perhaps for geal system, both in normal and abnormal minimal protection (less than 10 dB) at low conditions, and both in the adult and in frequencies. They also cited research the developing child. Thus, this review in- which indicated that stapedius contraction cludes normal, abnormal, and develop- is more closely associated with voicing and mental studies on middle ear musculature, coughing than with acoustic stimuli, and the auditory tube, the velopharyngeal that the middle ear muscles might be in- mechanism, the , the , the volved in auditory tube opening. face and , and blood supply and The literature reviewed for this report innervation relevant to cleft lip and palate. does not resolve all of these questions, but Though the relevance of embryology of it does add some focus for future research. the orofacial complex is obvious, it has Greisen and Neergaard (1975) used extra- been reviewed in a recently published re- tympanic phonometry to study middle ear port (Dickson, 1975) and will not be in- reflex activity and were able to demon- cluded as a separate topic in this review strate a tensor tympani reflex in response because of space limitations. Maxillary to acoustic stimuli only when a generalized growth and development, included in the startle response was provoked. They also previous report, will be covered in the cur- demonstrated that stapedius did not con- rent report under Section III, "Orofacial tract during the startle response. Like the Growth and Dentistry." data of Klockhoff (1959), Moller (1961), An effort has been made in the current Feldman (1967) and Solomon and Starr report to indicate areas in which signifi- (1963), their data indicated a close relation- cant contributions have been made during ship between stapedial contractions and the period reviewed as well as areas which acoustic stimuli. Greisen and Neergaard are still seriously in need of further defini- observed that during the startle response, tive research. As in the previous report, both tensor tympani and the auditory tube literature which largely reflects opinion muscles (especially tensor vel palatini) rather than data-based conclusions has not contract and give rise to small volume dis- been included. ' placements and subsequently to small changes in the pressure of the middle ear. They suggested that the muscles which open the auditory tube (they included lev- Dr. Maue-Dickson is Associate Professor of Pediat- rics, University of Miami, Mailman Center for Child ator veli palatini) may act synergistically Development, University of Miami, P.O. Box 52006, with the during Biscayne Annex, Miami, Florida 33152 . A similar hypothesis, i.e., that 270 Maue-Dickson, STATE-OF-ART (ANATOMY) 271 the middle ear muscles and tensor veli pal- widened by the tensor veli palatini muscle atini may act together in auditory tube and that maximal tubal dilation occurs to- clearance, was suggested in the previous ward the middle part of the canal, with less report (Dickson, et al. 1974, 1975) and still intense dilation at the pharyngeal ostium seems tenable since both the tensor veli and at the isthmus. Misurya's study of the palatini and tensor tympani muscles are in- levator muscles indicated that dilation of nervated by the fifth cranial . the isthmus lumen occurs with simultane- In summary, the consensus among the ous narrowing of the pharyngeal ostium authors reviewed here is that tensor tym- lumen. He was careful to emphasize, how- pani responds primarily and probably ex- ever, that the levator muscle cannot be clusively to non-acoustic stimuli and that considered to be an active lumen dilator stapedius responds primarily and probably since its fibers have no direct attachment to exclusively to acoustic stimuli. None of the the tube. He also demonstrated that the authors reviewed presented data in sup- concavity produced by the elevation of the port of a functional relationship between floor of the pharyngeal ostium is produced stapedius and non-acoustic stimuli or be- by contraction of the belly of the levator tween tensor tympani and acoustic stimuli. muscle. Misurya also successfully recorded Finally, while the question of the role of pressure changes from anterior and poste- the muscle(s) of the middle ear in auditory rior parts of the tube and found them to tube clearance has still not been resolved, differ but also learned that the net result the data reviewed suggest that both tensor was no change. tympani and tensor veli palatini play an The probably universal occurrence of important role in auditory tube clearance. middle ear effusion and hearing loss in As indicated in the previous review babies born with cleft palate continues to (Dickson, et al. 1974, 1975), the literature is be a source of concern. Glasscock (1971) replete with references to the very high has indicated that prolonged middle ear and probably universal incidence of mid- effusion may cause permanent damage to dle ear disease and hearing loss in infants the middle ear mechanism and may result born with cleft palate. While substantial in sensorineural as well as conductive loss. efforts have been made to determine the Bluestone, et al. (1972-a, 1972-b) have pro- possible role of the auditory tube in this vided further data on infants and children regard, the role of the middle ear muscu- with middle ear disease which again indi- lature still has not been investigated ade- cates that middle ear disease is often asso- quately. ciated with abnormalities in retrograde flow patterns through the auditory tube. 2. T'nmr AupIrorRry TUBE -His studies also suggest abnormal auditory A number of studies on auditory tube tube distensibility associated with cleft pal- anatomy and physiology in normal and ate. The research of Gerwat (1975) and cleft palate subjects have been published Bluestone and Cantekin (1975) further during the period of the current review. suggests that adenoidectomy will improve Lim (1973) published a comprehensive re- auditory tube function if mechanical ob- view of the functional morphology of the struction of the tube is present and chronic lining membrane of the middle ear and inflammation is absent (Bluestone and auditory tube. Koch (1963) published an Cantekin) or is the degree of adenoid en- excellent review of qualitative testing of largement, though insufficient to produce auditory tube function. Misurya (1975) total tubal obstruction, if sufficient to conducted an elegant study on the func- cause increased linear velocity of air flow tional anatomy of the tensor palatt and with a resultant intermittent negative pres- levator palati muscles in two dogs. Mis- sure around the pharyngeal orifice of the urya's study, which essentially replicated tube (Gerwat). the landmark studies of Rich (1920), dem- The question of the role of growth in the onstrated that the auditory tube canal is alleviation of middle ear disease associated 272 Cleft Palate Journal, October 1977, Vol. 14 No. 4 with cleft palate has still not been an- suggested that this could result in an alter- swered. However, several studies have ation of the biomechanics operating on the been published recently which bear on the auditory tube and that growth of the crani- question. Cole and Cole (1974) found that ofacial complex may play an important poor auditory tube function is not charac- role in the decreasing incidence of audi- teristic of cleft palate in the young adult tory tube malfunction in children with age group. Their research also indicated a cleft palate during the first few years of positive correlation between the level of life. observed pharyngeal wall activity and It is apparent that most of the data re- the adequacy of auditory tube function. ported recently on auditory tube function Brooks (1975) found the incidence of mid- still comes from indirect measures such as dle ear effusion to be no greater in se- the electro-acoustic bridge, and that very verely hearing-impaired individuals than little research has been done on the possi- in normal subjects at the age of 5 years. In ble anatomical, developmental, and bio- a study of newborn infants, Keith (1975) mechanical factors responsible for audi- discovered that all infants tested exhibited tory tube malfunction associated with cleft normal middle ear pressure and mobile palate. middle ear systems; they appeared to have well-aerated middle and showed no 3. T'ur® VELOPHARYNGEAL MECHANISM evidence of mucous or other fluid behind As indicated in the previous State of the the tympanic membrane. Art Report, there is a critical need for These studies thus support the view- further anatomical and physiological re- point that middle ear fluid is not charac- search in the areas of normal and cleft teristic of normal newborn babies and that palate to resolve questions regarding nor- it is no more common in cleft palate or mal patterns of velopharyngeal motion, hearing-impaired groups after the age of 5 the level of motion relative to the torus than it is in non-cleft palate groups. Yet, as tuberius, the role of specific muscles of the already indicated, there is ample evidence velum and pharynx in velopharyngeal that middle ear effusion is practically uni- anatomy and physiology, developmental versal in the newborn cleft palate group. morphology of the velopharyngeal mecha- Obviously, then, something causes mid- nism, and the specific innervation and dle ear effusion to decrease in incidence or blood supply of muscles of the velopharyn- to disappear in babies with cleft palate dur- geal mechanism. It was also pointed out in ing the first few years of life. Several stud- that review that descriptions of these areas ies have indicated that this may be one are far more deficient in the area of cleft benefit of early corrective surgery for cleft palate than in the normal condition. The palate (Korsan-Bengsten, 1974; Bluestone, current review has indicated that most of et al., 1972; Bluestone and Cantekin, 1975; these questions still have not been resolved and Gerwat, 1975). However, none of in spite of the many recent endoscopic, these studies rules out the possibility that ultrasound, cineradiographic, and electro- craniofacial growth may be an important myographic studies. consideration in this regard and that spon- A number of studies relevant to the pat- taneous improvement might occur even tern of velopharyngeal closure have been without corrective surgery. reviewed. A study of velopharyngeal com- The latter viewpoint was expressed as a petence following pharyngeal flap surgery hypothesis in the research reported by for cleft palate was conducted by Skolnick Maue-Dickson, et al., (1976) following a and McCall (1972) and indicated multiple histological study of the morphology of the patterns for velopharyngeal closure. The auditory tube and related cranial base authors emphasized the need for cine- or structures in age-matched human abor- video-fluoroscopic techniques in multiple tuses with and without cleft palate. They projections with simultaneous recordings found compression of all of the structures of speech and roentgen images for each lying between the lateral walls of the phar- - view. In 1973, Skolnick, et al. used multi- ynx and the side walls of the cranium and view videofluoroscopy to study the mecha- Maue-Dickson, STATE-OF-ART (ANATOMY) 273 nism of velopharyngeal closure. They did new technique utilizing simultaneous fron- not differentiate between lateral and pos- tal tomograms and lateral view x-rays for terior pharyngeal wall motion since they the assessment of degree and level of lat- view velopharyngeal closure as a sphinc- eral pharyngeal wall displacement relative teric activity. Like Peterson (1973), Skol- to the tongue, , and other struc- nick et al. observed that the number of tures during speech and non-speech activi- different patterns in subjects with velo- ties. The timing and speed of velar move- pharyngeal incompetency is greater than ments relative to articulatory activity was in subjects with normal velopharyngeal studied cineradiographically by Kuehn closure. In a cinefluorographic study, (1975). He found that palatal movements Sphrintzen, et al. (1974) observed two and were generally slower than tongue move- possibly three distinctly different patterns ments and that while velar velocities, dis- of velopharyngeal closure: pneumatic clo- placements, and transition times showed sure in speech, whistling, and blowing; considerable variation, depending on pho- non-pneumatic closure in dry swallowing netic context and speaker, velar transi- and gagging; and, perhaps, reflexive swal- tional displacements and durations were lowing. In a later study (1975) Shprintzen, consistently reduced with increased speak- et al. studied the first pattern further and ing rate in both subjects. In 1976, Kuehn found that the maximum medial excursion studied velar elevation and lowering move- of the lateral pharyngeal walls occurred at ments and, in agreement with Kent et al. the level of the full length of the velum (1974) found that the trajectory of normal and hard palate, well below the levator palatal movement appears to be fairly con- eminence. They hypothesized that this stant regardless of the magnitude or speed may be due to the select contraction of of movement and regardless of whether those fibers of the superior constrictor the palate is being elevated or lowered. muscle which enter the velum via the lat- Kuehn also found that the velopharyngeal eral walls and those fibers attached to the mechanism appears to adapt to variations pterygoid plates as well as to levator mus- in speaking rate such that adequate closure cle activity. is not compromised. Miyazaki, et al. (1975) have described fi- In 1973, Bell-Berti conducted a hooked- berscopic methods for the assessment of wire electromyographic study of various patterns of velopharyngeal closure during velopharyngeal muscles including the leva- various speech and non-speech activities. tor velt palatini, palatoglossus, palatophar- A fiberscopic study conducted by Matsuya, yngeus, superior constrictor, middle con- et al. (1974) provided further support for strictor, and sternohyord. Her results indi- the already established viewpoint that velo- cated that the levator muscle is the primary pharyngeal closure for swallow is constric- muscle of velopharyngeal closure for orali- tive, while that for speech involves differ- zation, that the amount of levator activity ential degrees of movement of the velum is correlated with the oral cavity imped- and lateral pharyngeal walls. Matsuya also ance of the articulated speech sound, that indicated that the velar and lateral pharyn- nasal articulation is accomplished by sup- geal wall motions in blowing, in which clo- pression of electromyographic activity in sure was achieved by " . . . posterior move- those muscles participating in oral articu- ment of the velum and medial movement lation, that the strength of electromy- of the lateral pharyngeal walls," are more ographic signals obtained from the lateral similar to those observed in closure for and posterior pharyngeal walls is effected speech than to those observed in swallow- by vowel color, that the pattern of velopha- ing. Flowers and Morris (1973) observed ryngeal activity was such that it would pro- that some cleft palate subjects who do not vide an increased pharyngeal cavity vol- achieve closure during speech do so dur- ume for voiced stop consonant produc- ing swallowing by the use of tongue-velar tion, and that velar and alveolar articula- pressure and increased pharyngeal wall tion may be responsible for the increased motion. magnitude of the electromyographic po- In 1975, Kuehn and Dolan described a tentials from the palatoglossus, middle 274 Cleft Palate Journal, October 1977, Vol. 14 No. 4

constrictor, and sternohyoid muscles. Bell- the superior constrictor during speech. Berti (1975) also reported on an electromy- The middle constrictor appeared to be ographic study of pharyngeal size and mus- more active in voiced, voiceless, and vowel- cle activity (levator, superior constrictor, consonant contexts than did the superior middle constrictor, and sternohyoid) dur- constrictor muscle. A correlative study of ing the production of stop consonants and velar height and levator activity using noted that while the feature of tension was hooked-wire electrodes was conducted by inadequate for the description of pharyn- Ushijima and Hirose (1974). The authors geal volume changes concommittant with felt that increased electromyographic ac- voicing distinctions, levator and sterno- tivity on consonants following nasals indi- hyoid activity was more prominent in the cated increased strength of contraction production of voiced stops than in the pro- needed to achieve closure, as opposed to duction of their voiceless cognates. increased maximum velar height or tighter In 1973, Kewley-Port found that consist- velopharyngeal closure. ent patterns of averaged electromyographic Zagzebski (1975) measured the degree of recordings were obtained from several lateral pharyngeal wall motion during different electrode placements on the leva- speech with ultrasound and found greater tor muscle, regardless of different am- medial displacements at the level of velo- plitudes of the maximum scale values pharyngeal closure than at the level of the among them. Based on this, Ushjjima and angle of the mandible, greater displace- Hirose (1974) inferred that the activity pat- ment for low vowels than for high vowels tern picked up from any one location on at the level of the angle of the mandible, the levator muscle should represent the and greater lateral wall motion for non- overall change in the motor command to nasal sounds than for nasal sounds at the the levator and that there are quantita- level of the velopharyngeal closure. He tively different neural commands for challenged the hypothesis of Dickson movements of the velum for consonants (1972) that the levator action at the level of and vowels. They also pointed out that the torus tuberius is responsible for maxi- decreased levator activity for lower vowels mum mesial movement of the lateral pha- should not necessarily be expected to coin- ryngeal walls during speech, and offered cide with proportional decreases in abso- support for the data of Shprintzen (1974), lute velar height. In an electromyographic which indicated that maximum mesial wall study of these questions, Ushjjima and Hi- motion occurs well below the levator emi- rose found that the velum is not controlled nence. by a simple on-off mechanism;, that there is An excellent discussion of the advan- no systematic segmented difference be- tages and disadvantages of the use of ultra- tween either voiced or voiceless or stop sound was provided by Ryan and Hawkins and fricative consonants, and that there (1976). They pointed out that while ultra- are different mechanisms for anticipatory sound is comfortable, safe as compared and carry-over effects of coarticulation at with x-ray, low in cost, and portable, it the level of the motor command. They also may be time-consuming and recordings observed that there seems to be no antici- may be difficult to interpret accurately. In patory lowering of the velum during the addition, variable thickness of the trace vowel segments before a syllable boundary may introduce serious errors in displace- in the CVV'VN environment. ment measurements, and interpretation is Minifie, et al. (1974) abserved apparent jeopardized by a dearth of normative data. inhibition of constrictor muscle activity In 1976, Zwitman, et al., conducted during voiced elements and some subtle re- an oral telescope and radiographic study duction during voiceless elements. They of velar and lateral pharyngeal wall motion also observed comparable amplitudes of which indicated that absent or restricted electromyographic responses from the su- lateral wall motion was more common in perior and middle constrictors during the subjects with cleft palate. swallow, but considerably less activity of The size of the velopharyngeal aperture Maue-Dickson, STATE-OF-ART (ANATOMY) 275 in cleft and non-cleft palate speakers with the levator muscle is responsible for the significant degrees of hypernasality was changes observed in the anterior portion studied with lateral x-rays by Carney and while the uvulus muscle is responsible for Morris (1971). They found the two groups changes in the posterior portion. This fits to be very similar in the frequency and well with the anatomy of the levator as magnitude of closure and in the lack of described by Dickson (1972) and the anat- correlation between severity of hyperna- omy of the uvular muscle as recently de- sality and the degree of velar constriction, scribed by Langdon (1976). pharyngeal constriction, oral constriction, Only two studies of motor nerve supply and incisor opening. They concluded that to the velopharyngeal musculature were the critical size of velopharyngeal opening found (Nishio, et al. 1976; and Nish10, et al. is variable and does not appear to be useful 1976). Both were conducted on rhesus in describing the relationship between the monkeys. By direct stimulation of various severity of nasality and degree of velopha- cranial within the skull, the authors ryngeal opening. It seems obvious that the obtained data which indicated that the lev- critical size of velopharyngeal opening de- ator, uvulus, and superior constrictor pends in large part on phonetic context muscles received double innervation via and on the relative levels of oral and nasal the facial nerve and via branches of the impedance. This was demonstrated by pharyngeal plexus derived from the glos- Benson (1972) in a roentgenographic ce- sopharyngeal and vagus nerves and that phalometric study of velopharyngeal clo- the facial nerve played an important role sure during vowel formation. Benson in velopharyngeal closure. Using a naso- demonstrated that a residual velopharyn- pharyngeal fiberscope and photographic geal lumen is present in 62 per cent of equipment to record the results of direct normal individuals phonating /a/, 23 per nerve stimulation, they observed that velo- ient phonating /i/, and 9 per cent phonat- pharyngeal movements were the most ac- ing /u/. Measurements of mean palatal tive on stimulation of the vagus, less active height during velopharyngeal closure fur- on stimulation of the glossopharyngeal, ther supported these findings. Posterior and least active on stimulation of the facial pharyngeal wall motion in normal individ- nerve. Complete closure by unilateral uals was found to be minimal during vowel nerve stimulation was elicited only by the production and the atlas was found to be vagus, though in some cases, velopharyn- too variable to be a dependable landmark geal closure was also achieved by bilateral in the assessment of velopharyngeal clo- stimulation of the seventh cranial nerve. sure. Combined stimulation of the three nerves As indicated in the previous review, the (VII, IX, and X) sometimes resulted in an velum is longer during velopharyngeal clo- additive effect. The authors concluded sure than during rest. Simpson and Austin that the motor nerves innervating the velo- (1972) used lateral x-rays to study velar pharyngeal muscles play different roles in stretch during rest and during the phona- velopharyngeal movements. Motion ob- tion of /s/, and found that, while signifi- served on stimulation to the vagus or glos- cant stretch occurred for the entire velum sopharyngeal nerve was similar to that ob- during velopharyngeal closure, the poste- served in swallowing in human subjects, rior portion exhibited a greater degree of while stimulation to the facial nerve re- stretch than did the anterior portion, and sulted in velopharyngeal motion similar to that, during stretch, the anterior portion that observed in phonation in human sub- decreased in thickness while the posterior jects. It should be noted that innervation portion increased in thickness. They also equivalence between the rhesus monkey indicated that stretch in the anterior por- and man has not yet been demonstrated. tion appeared to be related to the degree In summary, the studies reviewed for of structural adequacy of the velopharyn- the current report support previous data geal mechanism while that in the posterior indicating that the patterns of velopharyn- portion did not. They hypothesized that geal closure differ for speech and for swal- 276 Cleft Palate Journal, October 1977, Vol. 14 No. 4

lowing (Flowers and Morris, 1973; Mat- that the muscle is the suya, et al., 1974; and Minifie, et al., 1974), primary muscle of velopharyngeal closure while the patterns for speech and blow- for oralization. Further elucidation of velo- ing are similar (Matsuya, et al., 1974; pharyngeal activity was provided by the Shprintzen, et al., 1974). Degree, strength, electromyographic studies of Kewley-Port and pattern of velopharyngeal closure; de- (1973) and Ushijima and Hirose (1974). gree and level of the lateral pharyn- Shelton and Trier (1976) presented a re- geal wall movement; and rate and timing view which summarized the problems of of velar and tongue movements during fluoroscopic examination of velopharyn- speech activities appear to depend on spe- geal closure and addressed serveral impor- cific speech environment, e.g., low or high tant issues, including procedural problems vowels, nasal or non-nasal sounds, and in the fluorographic examination of the speaking rate (Benson, 1972; Ushjima and velopharyngeal mechanism and the need Hirose, 1974; Kent, 1974; Zagzebski, 1975; for non-fluorographic measures and for Kuehn, 1975, 1976; and Minifie, et al. 1974). validation of measures. A challenge has been offered to Dick- son's (1972) hypothesis that the maximum The Tongue and Facial Musculature mesial movement of the lateral pharyngeal walls during velopharyngeal closure for Only one study of normal anatomy of speech occurs at the level of the torus the intrinsic lingual musculature was tubarius and is produced by the levator found (Barnwell, 1975). The author con- palati muscle (Skolnick, e al. 1973; ducted a nicely designed study of the stylo- Shprintzen, et al., 1975; and Zagzebski, glossus muscle in one cadaveric adult 1975). The consensus on velopharyngeal tongue, utilizing micro-dissection, and in closure patterns is that they are variable fourteen 15-week human abortuses, utiliz~ but are more variable in velopharyngeal ing serial histologic sections. She demon- incompetence than in normal conditions strated that the muscle origi- (Carney and Morris, 1971; Skolnick and nates either from the stylorid process or McCall, 1972; Skolnick, et al., 1973; Peter- from the sphenomandibular ligament and son, 1973; Shprintzen, et al. 1974; and that it then courses anteriorly, medially, Zwitman, et al. 1976). and inferiorly to the lateral border of the With regard to the role of specific mus- muscle at the base of the cles in velopharyngeal activity for speech, tongue. Here it divides into two sections: a Simpson and Austin (1972) hypothesized posterior bundle which turns medially to that anterior velar stretch in velopharyn- terminate at the lateral border of the gen- geal closure may be related to levator ac- ioglossus muscle and an anterior bundle tivity while posterior velar stretch is prob- which courses to the tip of the tongue lat- ably related to uvular muscle activity. eral to the hyoglossus muscle and inferior Shprintzen (1975) hypothesized that the to the palatoglossus and superior longitu- maximum medial excursion of the lateral dinal muscles. In the anterior third of the pharyngeal walls, which he observed to tongue, styloglossus fibers were found to occur at the level of the full length of the converge with fibers of the hyoglossus and hard palate and velum, may be due to inferior longituidinal muscles, and , in fetal select contraction of the upper fibers of specimens, with oblique fibers rising from the superior constrictor muscle as well as the lamina propria. The author also found to the levator muscle. Minifie, et al. (1974) the styloglossus to vary in bulk, length, suggested some degree of inhibition of the and symmetry. _ superior constrictor muscle during speech Only two additional anatomical studies with more activity of the middle constric- of the tongue were found. Soames (1973) tor muscle than of the superior constrictor conducted a histologic study of 100 cadav- muscle in the production of voiced-voice- eric and found no evidence of less and vowel-consonant contrasts. either the thyroglossal duct or of thyroid Bell-Berti (1973, 1975) presented electro- tissue but did find that lymphoid tissue was myographic data which again indicated present in association with the epithelium- Maue-Dickson, STATE-OF-ART (ANATOMY) 277

lined pit in half of the cases studied. Mu- (1962) examined the contents of the pro- cous and serous glands were present in all labium via tissue biopsies from 15 pa- cases but showed no regular pattern of tients with cleft lip. Sections prepared from distribution. Fletcher and Daly (1974) mea- these biopsies indicated that muscle tissue sured sublingual dimensions in 50 chil- was absent or markedly diminished in all dren. Based on their data, the authors sug- cases and that normal muscle bundle ar- gest several "rules of thumb" for the iden- chitecture was not present. Three addi- tification of tongue-tie: inability of a child tional tissue biopsies from "older children" to raise his tongue tip to contact the alveo- with unoperated complete bilateral clefts lar ridge, to move a protruded tongue were also found to contain no muscle tis- from one corner of the mouth to the sue. In addition, the authors collected other, or to achieve contact for lingua- electromyographic recordings from the dental and lingua-alveolar consonants; a prolabia of four subjects with secondary "notching" of the tongue when the tongue bilateral clefts. None showed normal ac- tip is protruded; or sublingual restriction tion potential, indicating that the motor that prevents the tongue from being pro- units in these prolabial segments were truded beyond the lower gum. either sparse or absent. The authors ob- No studies of lingual anatomy in cleft served that incomplete clefts of the lip are palate were found in the current review. characterized by relatively more muscle tis- However, in an experiment in mobiliza- sue than are complete clefts although the tion of the palatine bones of cleft dogs, tissue is still not normal in amount or func- Latham and Smiley (1973) picture, but do tion. The absence of anatomically and not describe, a coronal histologic section functionally significant muscles in the pro- through the head of a 17-week human labium in bilateral clefts of the lip was also abortus with complete cleft of the second- observed by Duffy (1971), who found that ary palate. The tongue configuration ap- muscle tissue in the philtrum probably pears to be abnormal and is identical in comes exclusively from the lateral seg- gross character to similar sections from fe- ments in normal development. tuses with cleft palate examined by the Several excellent electromyographic stud- author. There is clearly a need for further ies of normal lingual musculature, both study of lingual anatomy associated with extrinsic and intrinsic, and of normal clefts of the palate. facial musculature have been published The specific morphology of the orbicu- during the current review period. In 1974, laris oris muscle in normal and cleft palate Bell-Berti and Harris investigated the elec- subjects is still a subject of interest. Several tromyographic activity of the early reports on this muscle in the child muscle in three normal English speakers in with cleft lip not reviewed in the previous - an attempt to identify instances of antici- report have been found as well as several patory coarticulation at the motor com- more recent reports. In 1946, Lee de- mand level. Their hypothesis was that elec- scribed the from tromyographic activity would merge for histologic sections in a five-month old ne- sequences moving toward a more closed groid female child with a bilateral cleft lip vocal tract. They found that, when the and cleft palate. Contrary to the usual text- sequence involves moving from a more book descriptions of this muscle in the nor- open to a less open vocal tract, only one mal adult, he found no concentration of peak of electromyographic activity is pres- purely sphincteric muscle fibers at the cor- ent. However, when the reverse motion is ner of the mouth. Instead, the orbicularis observed, two separate peaks of electromy- oris muscle was found to consist primarily ographic activity occur. of a heavy mass of horizontal fibers, which Miyawaki, et al., (1975) published a pre- extended close to the free border of the liminary report on an electromyographic lip, and of only relatively few sphincteric study of the activity of lingual muscles in muscle bundles. The fibers of the muscle one adult subject. They utilized hooked- thinned out and fragmented markedly as wire electrodes inserted perorally and per- they approached the ala of the nose. Rees cutaneously at five different locations on 278 Cleft Palate Journal, October 1977, Vol. 14 No. 4

the genioglossus muscle and made sound graphic study of labial and lingual mus- recordings simultaneously during the ex- 'culature in labial stop consonant produc- perimental speech tasks. They also dis- tion in Danish speakers. Specific muscles sected and stimulated four twigs of the studied included the orbicularis oris supe- twelfth cranial nerve supplying the medi- rior and inferior muscles, the depressor oposterior fibers of the genioglossus mus- anguli oris, the depressor labii inferioris, cle in a dog. It was observed in the latter - and various laryngeal muscles. They part of the experiment that the stimulation found that orbicularis oris superior and of a twig caused a distinctly localized con- inferior both showed strong activity dur- traction of a limited portion of the genio- ing lip closing, while strong orbicularis glossus muscle. The authors felt that these oris inferior activity occurred during lip findings supported observations on hu- rounding. man subjects that electromyographic sig- Gay (1974) studied the effect of speaking nals recorded simultaneously from differ- rate on the articulation of the consonant- ent locations on the genioglossus muscle vowel articulation in two normal adult differed characteristically in their active male speakers. By the simultaneous use of patterns and, therefore, that genioglossus high-speed lateral view x-rays of the consists of a number of components or tongue and jaw and electromyographic re- subdivisions capable of contracting sepa- cordings from muscles which control lip, rately. They also indicated that the genio- tongue, and jaw movements, he was able glossus muscle is active for vowels charac- -to demonstrate that, for labial consonant terized by "high" and/or "front" positions, \ production, increased speaking rate is ac- while it shows little activity for vowels companied by increased activity of the or- which are neither high nor front. The bicularis oris muscle and slightly increased question of validity in this study needs fur- rates of lip movement. Conversely, as ther attention. While there is little consen- speaking rate was increased, vowel pro- sus in the literature regarding the. specific duction was accompanied by decreased function of any of the extrinsic and intrin- genioglossus activity and evidence of tar- sic lingual muscles in man, the authors get undershoot. Jaw displacement was enumerate the functions of the anterior generally decreased during fast speech, a belly of the digastric, the geniohyord, the finding inconsistent with the observations styloglossus, the genioglossus, and the of Abbs (1973), who found little effect of transverse and superior longitudinal mus- speaking rate on jaw displacement. cles of the human tongue. Only one study relevant to human lin- Raphael (1974) conducted a concentric- gual innervation was found. Borden and needle electromyographic study simulta- Harris (1973) conducted an electromyo- neously with voice output recordings on graphic study of speech under trigeminal vowels preceding voiced and voiceless con- nerve-block anesthesia. Tongue muscles sonants in English with two subjects. Mus- studied included the genioglossus, genio- cles recorded included the orbicularis oris, hyoid, and superior longitudinal. The sig- depressor anguli oris, inferior longituid1- nificance of their conclusions is the as- nal, mylohyoid, and genioglossus. Their sumption that the effects of the tradition- results indicated the possibility of sus- ally used nerve-block are purely sensory. tained muscular activity in the articulatory The authors observed that other muscles gesture for vowels preceding voiceless con- were either depressed during the block or - sonants. They also noted that acoustically more active than normal and suggested determined differences between duration that the electromyographic amplitude re- of muscular-articulatory gestures for the corded depends on the depth of anesthesia vowels and temporal displacement of the and upon idiocyncratic reactions of the final consonant peaks generally showed subjects. They observed that changes in very similar values. muscle activity during the nerve-block ex- Fischer-Jorgensen and Hirose (1974) tended even to those muscles whose sen- conducted a hooked-wire electromyo- sory and motor nerves cannot be affected Maue-Dickson, STATE-OF-ART (ANATOMY) 279

by the block and, therefore, suggested that of orbicularis oris activity, and increased the effects observed indicate a more cen- rates of lip movement. Finally, only two tral effect or some compensatory reorgani- studies relevant to lingual innervation, one zation. They found that muscles innerv- human and one on the dog, were found ated by the blocked nerve were consist- (Borden, et al. 1973; and Miyawaki, et al. ently depressed or inactive. Thus, despite 1975). attempts to anesthesize only the , the anesthesia must have infil- The Larynx trated. They also found that muscles pre- Very few studies have been published sumably associated with sensory fibers recently on developmental morphology, from the blocked nerve and those which adult structure, or function of the human should be independent of the blocked larynx, and only two of these concern the nerve behaved erratically. individual with cleft palate. Too-Chung No definitive studies were found on lin- and Green (1973) reported a study of cri- qual blood supply or developmental anat- cord cartilage dimensions in post-mortem omy. Neither were any studies found specimens ranging in age from neonatal to which compared lingual anatomy in cleft 15 years in which they found that the palate with the normal condition even child's cricord cartilage is typically ellipti- though there are strong suggestions that a cal with the coronal diameter greater than difference in lingual anatomy does exist the sagittal, that cricoid growth rate in between these two groups. these two dimensions relative to body In summary, very little work has been weight is linear, and that the primary pre- done during the current review period on dictive value for cricord area was weight. the anatomy of the tongue or facial muscu- They did not find any significant sex dif- lature either in normal individuals or in ferences. In 1975, Kahane conducted a individuals with cleft palate. Several arti- study of the morphology of the circum- cles published prior to 1972 were found on pubertal human larynx. He found that, anatomy of the orbicularis oris muscle in with the possible exception of width and cleft lip and palate (Lee, 1946) and on the posterior height of the arytenoid cartilage, prolabium in cleft lip (Rees, 1962; Duffy, none of the sex differences observable in 1971). Recent electromyographic studies adult male and female larynges were pres- on labial, lingual, and facial musculature ent in the prepubertal group but that all have added new information on co-articu- were present in the pubertal group. latory gestures, muscle function, and mo- Growth of the larynx was found to be lin- tor control of speech. Bell-Berti and Har- early related to growth in body height but ris (1974) indicated that genioglossus activ- was less well related to chronological age. ity is different for speech sequences involv- Several studies of laryngeal muscular ac- ing movement from a more open to a tivity were reported during the current more closed vocal tract than for the re- review period. Gay, et al. (1972) studied verse condition. Miyawaki, et al. (1975) intrinsic laryngeal muscle formation elec- found strong genioglossus activity during tromyographically during phonation. The high and front vowel production. Raphael authors found that, in general, increases (1974) found some evidence for sustained in fundamental frequency were accompa- muscular activity in the articulatory ges- med by progressive increases in the activity tures for vowels preceding voiceless con- of the cricothyrord and vocalis muscles, sonants. Fischer-Jorgensen and Hirose that the posterior cricoarytenoid activity (1974) found that both the orbicularis oris increased at high fundamental frequen- superior and inferior muscles were active cies, that muscle activity pattern was the during lip closing while only the inferior same at both low intensity and high inten- muscle showed strong activity during lip sity, and that in general higher frequency rounding. Gay (1974) found that increased steps were characterized by only slight in- speaking rates were associated with de- creases in adductor activity. In describing creased jaw displacement, increased levels increased posterior cricoarytenoid activity 280 Cleft Palate Journal, October 1977, Vol. 14 No. 4 at high fundamental frequencies, the au- interarytenoid, posterior cricoarytenoid, thors state that posterior cricoarytenoid thyroarytenoid (vocalis), lateral cricoaryte- may act as a tensor of the vocal folds. They noid, and cricothyroid muscles in six Dan- also described the cricothyroid and vocalis ish speakers. They found that the activity muscles as primary in the control of funda- of the interarytenoird was strong when the mental frequencey and demonstrated that preceding consonant was accompanied by activity of the vocalis muscle, and often of a large glottal opening. Previous work by the cricothyroid, decreases in a shift from the authors had suggested that the vocalis chest voice to falsetto. ' and lateral cricoarytenoid were generally A second hooked-wire electrode study active during vowels and inactive during - conducted by Hirose and Gay (1972) indi- consonants. Their current research indi- cated posterior cricoarytenoid activity for cated a far more complex but still not com- voiceless consonants and suppression of its pletely deciphered pattern of activity. Hi- activity for voiced consonants, while the rose, et al. (1974) investigated laryngeal reciprocal pattern was observed for the control in Korean stop production. Their interarytenoid muscle. It was observed by results indicated that, at least in Korean the authors that the posterior cricoaryte- stops, laryngeal articulatory activity is not noid activity did not follow an all-or-none limited to simple adduction/abduction of type pattern and that the interarytenord the vocal folds. Hirose and Ushjima (1974) showed less activity for voiced fricatives also studied the function of the poste- than for vowels. Hirose and Gay (1973) rior cricoarytenoid muscle during speech. also conducted an electromyographic They found that glottal opening for word- study of laryngeal control in vocal attack of medial voiceless stops and geminates is three types: breathy or aspirate, soft or generally smaller than for voiceless fricta- simultaneous, and hard or glottal. Each tives or devoiced vowel segments and that type was found to be characterized by co- the degree and timing of posterior cricoar- ordinated or reciprocal action of the ab- ytenoid activity are directly responsible for ductors and adductors, although the tim- determining the size and temporal course ing was different in each. In breathy and of glottal opening for voiceless segments. aspirate attacks, the posterior cricoaryte- They noted that suppression of the adduc- noid was found to remain active through- tors may also have to be considered for a out the prephonatory period up to the complete description of voiceless segment point immediately preceding phonation. production. As the posterior cricoarytenoid shut down, Collier (1974) assessed the degree to interarytenoid, vocalis, lateral cricoary- which laryngeal activity and subglottal air tenoid, and cricoarytenoid activity was pressure affect the rate of vocal fold vibra- found to increase abruptly. In hard at- tion in speech. Electromyographic and tacks, however, the posterior cricoaryte- subglottal air pressure recordings made si- noid activity was found to decrease earlier multaneously suggested that the gradually and the lateral cricoarytenord activity was falling baseline of a fundamental fre- found to increase earlier, while the inter- quency contour is controlled by the slowly arytenoid, vocalis, and cricothyroid also decreasing subglottal air pressure while showed prephonatory activity followed by major deviation from this baseline is a fall. In soft attacks, the posterior crico- caused by cricothyroid muscle activity. In- arytenoid activity was found to be sup- creased cricothyroid activity was found to pressed during the prephonatory period raise the fundamental frequency. Sus- while activity of the adductors and the tained contraction maintained high funda- cricothyroid increased steadily reaching a mental frequency, and relaxation lowered peak after the onset of voicing. fundamental frequency. As a part of their electromyographic Five studies of laryngeal innervation study of labial and laryngeal muscles in were found in the current review. Wyke stop consonant production, Fischer-Jor- (1974) suggested that the precise control gensen and Hirose (1974) studied the evident in laryngeal activity results from Maue-Dickson, STATE-OF-ART (ANATOMY) 281

three reflexogenic systems (mucosal, artic- such a group of early developing embryos ular, and myotatic). He studied the latter confirms the considerable role of inter- in cats and in man. His findings indicated muscular coordination within the laryn- the presence of sparsely distributed muscle geal musculature. spindles, "relatively small in size," and nu- Pearson (1975) conducted an elegant merous spiral nerve endings, which he study of human laryngeal microcirculation concluded were probably the primary me- in 20 normal adult human larynges by mi- chanoreceptors. His conclusions regarding crodissection and serial sectioning after human mechanoreceptor activity must be clearing of soft tissues and opacification of considered to be hypothetical since his ex- arterial and venous circulation. He found perimental work with electromyography that mucosal capillary beds exhibited ran- was on cats. dom orientation in the epiglottis, ventricu- In a study of the ganglion of the internal lar folds, and ventricles, that capillaries of laryngeal nerve, Ramaswamy and Kulase- the vocal folds lay parallel to the folds, that karan (1974) dissected or sectioned lar- subglottic capillaries radiated from the an- ynges from human abortuses and from terior commissure, and that posterior cri- cadavers ranging in age from 12 to 66 coid capillaries ran longitudinally from su- years. Their findings established the pres- perior to inferior. Muscles tended to be ence of single bilateral ganglia in the ma- supplied from their margins by tortuous jority of specimens studied and of two or arterioles of the nearby vessels, and longi- more masses in several cases. The gan- tuidinal capillary beds branched from glion, located on the internal laryngeal their vessels in the long axis of the muscle nerve at the level of the saccule, exhibited fibers. The cartilage was found to be avas- cell structure which was multipolar with cular while the perichondrium was found eccentric nuclei, suggesting parasympa- to be distributed uniformly with fine inter- _ thetic function, e.g., stimulation of the connecting arterioles. Vessels were ob- glands of the saccule for lubrication of the served to penetrate to all sites of ossifica- vocal folds. tion. Finally, it was found that deeper arte- Based on a study of the internal branch rioles and of the submucosa sup- of the superior laryngeal nerve during and ply the epiglottus from its periphery with after its anesthetization, Tanabe, et al. its midline area remaining less vascular. (1975) hypothesized that this nerve may Several studies of laryngeal function rel- play an important role in precise control of evant to cleft palate subjects have also been fundamental frequency without, however, published recently. Hamlet (1973) con- affecting overall or gross control of phona- ducted an ultrasound study of vocal fold tion. vibration during the production of hyper- Kratz (1973), in a description of a new nasal sounds and found that the open quo- microsurgical technique for the identifica- tient of the vibratory cycle is generally tion and protection of the laryngeal motor lower for nasalized vowels than for non- nerves during thyroid and laryngeal sur- nasalized vowels. Lowry, et al., (1974) used gery, described the location and position a laryngeal mirror to examine the larynges of the recurrent laryngeal nerve in over of 74 children with cleft palate. Seventy- 100 surgical exposures of the nerve. He two of the children exhibited normal lar- found that the recurrent laryngeal nerve ynges; one had thickened edematous and always divides before entering the larynx reddened vocal folds; and another ap- but that the divisions are sometimes so peared to have very short vocal folds in the close together that they might not seem anteroposterior dimension. However, no separate to the naked eye. attempt was made to correlate these find- Malannino (1974) conducted a histologic ings with a non-cleft palate control group study of neuromuscular spindles in the or with acoustic observations (e.g., hoarse- posterior cricoarytenoid and thyroaryten- ness). McWilliams, et al. (1973) published a oid muscles in human abortuses and report on vocal fold abnormalities in 27 pointed out that evidence of spindles in children with borderline velopharyngeal 282 Cleft Palate Journal, October 1977, Vol. 14 No. 4 valving problems which indicated that vo- cently. The posterior cricoarytenoid mus- cal fold pathology, particularly vocal nod- cle has been studied electromyographically ules and hoarseness, were common occur- by Hirose and Gay (1972), Fischer-Jorgen- rences in this group. The authors indi- sen and Hirose (1974), and Hirose and cated that increment in chronological age Ushjima (1974). In these studies, it was is the most important single factor in the shown to be active for voicless consonants remission of vocal pathology and that sur- but suppressed for voiced consonants and gical removal of vocal nodules is usually to be important in determining the size insufficient unless it is accompained by and timing of glottal opening for voiceless correction of the velopharyngeal valving segments. The interarytenoid muscle problem. seems to be more active for vowels than for Laryngeal embryology continues to be a voiced fricatives (Hirose and Gay, 1972) largely unexplored area. Tucker and and more active after consonants with Tucker (1975) cited the stages at which large glottal openings than after those with specific laryngeal structures are identifia- small glottal openings (Fischer-Jorgensen ble. They also pointed out, once again, the and Hirose, 1974). The vocalis and crico- problem of aging human embryos and fe- thyroid muscles again have been linked tuses because of variations in growth rate with control of fundamental frequency and the rarity of accuracy of the mother's (Gay, et al., 1972; Collier, 1974). It is appar- report of last mensus as a predictor of the ent that laryngeal articulatory activity is date of conception. They challenged the not limited to simple abduction/adduction validity of the view that the fetal period maneuvers of the vocal folds (Hirose, et merely represents an extension of matura- al., 1974), and it has been demonstrated tion of the dynamics of the embryonic that timing of the reciprocal activity of the stage and reiterated the urgent need for a abductors and adductors is different for significantly large, closely graded, well- breathy, soft, and hard vocal attacks. documented series of fetal larynges which Two studies reviewed (Lowry, et al., could perhaps be obtained via the pooling 1974; McWilliams, 1973) dealt with vocal of resources. fold problems in cleft palate. Lowry found In summary, only two studies (Too- that the vast majority of cleft palate sub- Chung and Green, 1973; and Kahane, jects examined had normal larynges while 1975) were found of laryngeal cartilage di- McWilliams found vocal pathologies to be mensions. Both studies suggested a lack of a common occurrence. prepubertal sex differences. Several sig- Hamlet (1973) studied vocal fold vibra- nificant studies of laryngeal anatomy have tion during the production of hypernasal been reported recently. Wyke (1974) dem- vowels and found the open quotient to be onstrated the presence of sparsely distrib- lower than for non-nasalized vowels. uted neuromuscular spindles and numer- Finally, Tucker and Tucker (1975) have ous spiral nerve endings in various laryn- reiterated the need for further fetal laryn- geal muscles. Malinnino (1974) found neu- geal research with significantly large and romuscular spindles in the posterior crico- closely-graded specimen series. arytenoid and thyroarytenoid muscles of It is clear that there is a very real need human larynges and linked their presence for further definitive research on laryn- with intermuscular corrdination. Kratz geal anatomy, physiology, and develop- (1973) described the anatomical location of mental morphology in normal individuals. the recurrent, laryngeal nerve. Ramas- In the area of cleft palate, the need re- wamy and Kulasekaren (1974) described mains urgent. the internal laryngeal nerve ganglia as typ- ically single bilateral structures which are Craniofacial Innervation and Blood probably parasympathetic in function. Supply Human laryngeal microcirculation was de- The current section will cover only those scribed in detail by Pearson (1975). areas of innervation and blood supply not Several significant studies of laryngeal specific to areas previously discussed in physiology have also been published re- this report. Maue-Dickson, STATE-OF-ART (ANATOMY) 283

Freeland and Rogers (1975) studied the monitor speech is of primary importance vascular supply of the cervical skin with only during the learning of speech." _ colored silicon rubber injections on abor- Abbs (1973) used a special application of tuses and adult cadavers. They found that nerve block anesthesia which presumably the skin of the neck anterior to the trape- suppressed gamma efferent fibers while zius muscle is supplied by descending leaving alpha efferent fibers unaffected. branches of the transverse cervical and su- He measured jaw displacement, velocity, pracapular arteries. These branches were and acceleration under both normal and found to pierce the platysma where they gamma block conditions in two normal anastomose to form a fine superficial net- subjects. Their data suggested that, under work of vessels which also run in a vertical gamma block conditions, disruption or ab- direction. The venous drainage was found sence of spindle afferent facilitation to al- to run in a descending direction at all pha motoneurons occurs. The author levels of the cervical skin. Allen, et al. suggested that under normal conditions (1973) provided an excellent and detailed the spindle motor system operates more description of the anatomy of the maxil- clearly under conditions of movement in lary . Storrs (1976) described the which large values of acceleration, veloc- course of the stapedial artery and pointed ity, and displacement are required. He out that most of the craniofacial anomalies also suggested that the spindle motor sys- which have been reported concern the tem is important in orofacial movements persistence of this artery. Baumel (1974) during the production of speech. has provided an extensive (90 reference) - Finally, one study published prior to the review of the literature on trigeminal-fa- current review period but not found in the cial nerve communication which deserves previous State-of-the-Art review should be to be read in its entirety by those inter- cited. King (1954) conducted an extremely ested. Pon (1976) gave a description of inciteful and elaborate study of both the anomalies of the facial nerve and middle blood supply and innervation of the crani- ear ossicles. White and Verma (1973) con- ofacial complex in four human abortuses. ducted a study of the spatial arrangement He dissected the face in one normal full- of facial nerve fibers in 15 human tem- term abortus and in one full-term abortus poral bones which indicated that the nerve with a complete bilateral cleft of the lip shows two main divisions which divide di- and palate. He also histologically sectioned chotomously to send fibers to both the up- and analysed the same area in a normal per and lower face. In addition, they seven-month-old abortus and in a second found a free mixing of fibers by several full-term abortus with a complete bilateral anastomosing branches between the two cleft of the lip and palate. Only a brief primary divisions. Borden, et al. (1973) summary of his findings is given here. He used bilateral mandibular nerve blocks in a found that the sockets for the incisor teeth study designed to determine whether or were more shallow in the cleft specimen not skilled speech is an open-loop system and that, while the subvomerine processes requiring little or no feedback from the were present, there were no facial or pala- periphery or a closed-loop system requir- tal processes. The arterial supply of the ing sensory information to control the pro- main tubercle was found to be derived duction of speech. Their findings indi- from the left via the arching cated that the effect of nerveblocking is trunk which crossed the nasal bone to subtle, limited, and manifested only in reach the midline and then transversed the rapid connected speech. The effect was columna naris and philtrum. The veins limited to /s/, /z/, f/, /t/, /r/, and /I/. They exhibited similar arches but emptied into concluded that, " . . . The high degree of the anterior facial veins on both sides. intelligibility of all of the speakers in the Large trunks of the intraorbital nerves study gives some weight to the theory that traveled with the anterior trunk to reach skilled speech may be largely under open the median tubercle. The incisors had a loop control," and they stated that, " . . . It "copious blood supply" from the facial may be that the oral sensory system used to arch but no nerve supply, and the anterior 284 Cleft Palate Journal, October 1977, Vol. 14 No. 4 dental nerves, after transversing the max- answers as yet regarding normal patterns illae, joined the intraorbital trunks. The of velar and lateral pharyngeal wall activ- author discussed the normal development ity, level of activity, sex differences, or of the philtrum and premaxillary region in specific innervation and blood supply to light of the cleft specimens studied and the velopharyngeal complex. It does seem - stated that in abnormal conditions the clear that patterns of velopharyngeal clo- nerves may wander far from their normal sure for speech and blowing are similar to sources. He also stated that the distribu- each other but differ substantially from tion of sensory nerves cannot be used with those observed in biologic closure. A major confidence in the determination of the em- problem in the investigation of these ques- bryonic origin of adult tissues. tions is still both a basic science and a tech- nical issue. Specific muscular anatomy and Summary and Discussion physiology is still not well understood, Regarding middle ear musculature, the and, therefore, validation of electrode current consensus is that tensor tympani placement in electromyographic studies responds primarily and probably exclu- and correct interpretation of cineradi- sively to non-acoustic stimuli and that sta- ographic and ultrasonic recordings contin- pedius responds primarily and probably ues to be a source of concern. Rate and exclusively to acoustic stimuli. The role of timing in velopharyngeal closure in speech the middle ear muscles in auditory tube and non-speech activities lacks definitive clearance has still not been resolved, but description. there are some data which suggest that the Our understanding of the tongue is still tensor tympani works with the tensor veli vague. More studies like that of Barnwell palatini in this function. Thirdly, the role (1975) on specific lingual muscular mor- of the middle ear musculature in middle phology must be conducted before defini- ear disease, particularly in cleft palate, has tive electromyographic studies of individ- not been determined and clearly needs ual human lingual muscles can be done. further study. No definitive works on lingual innervation There is convincing evidence that mid- or blood supply have been reported re- dle ear effusion is probably universal in cently in either normal or cleft palate newborn infants with cleft palate. Recent groups. studies have indicated that fluid is not Several electromyographic studies have present at birth in normal infants and that added to our information on laryngeal by the age of five years it is no more com- physiology, but, as in velopharyngeal and mon in cleft palate or hearing impaired lingual research, validation of electrode groups than it is in normal groups. The placement continues to be a problem be- reasons for the apparent decrement in the cause of the lack of definitive information extremely high incidence of middle ear about muscular anatomy. There is con- effusion in the cleft palate groups during flicting information on the prevalence of the first few years of life have not yet been laryngeal pathology in cleft palate individ- determined and need further study. It has uals, and the studies which have been done been suggested that palatal surgery, aden- have served primarily to emphasize the oidectomy in selected cases, and growth need for further investigation in this area. may be important factors in this regard. It also seems apparent that more atten- Since the trends seem to be the same in tion must be paid to the limitations, valida- operated and unoperated groups, the ma- tion, and multiple-approach use of many jor corrective factor may well be growth of of our research tools. Too often in the the craniofacial complex during the first research reviewed, it seemed probable that few years of life. results were too "Tool-specific" and too There are still numerous questions "subject-specific." which need to be answered regarding velo- As a general comment, there have been pharyngeal anatomy in both normal and few studies of the craniofacial complex cleft palate individuals. There are no final which have dealt with questions of variabil- Maue-Dickson, STATE-OF-ART (ANATOMY) 285 ity in normal or cleft palate populations. (no year given, probably 1975). There is still an urgent need for well-de- CARNEY, P. J., MorRIS, H. L., Structural correlates of nasality, Cleft Pal. J., 8, 307-321, 1971. signed developmental studies in all areas CoLr, R. M., CoLr, J. E., Eustachian tube function in reviewed. Finally, there does not seem to cleft lip and palate patients, Arch. Otol. 99, 337-341, be much interdisciplinary "pooling" of 1974. ' data. CoLLIER, R., Laryngeal muscle activity, subglottal air pressure, and the control of pitch in speech, Has- Part of the summary of the previous kins Labs., status report on speech research, SR 39/ State of the Art Report bears repetition: 40, 137-170, 1974. There is an urgent need for further ana- Dickson, D. R., Anatomy of the normal velopharyn- tomical research in all areas of the crani- geal mechanism, Clin. Plast. 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