A Functional Study Of The PalatalAnd Pharyngeal StructuresT. M. GKARER, D.D.S., Ph.D.",KENNETH K. BZOCH, Ph.I .*", andTSUNEO AOBA, D.D.S.*"*Chicago, IlliiioisKecent contributions to orthodonticliterature have criticized the static ap-proach of examining a denture at rest,with the teeth artificially articulatedby means of plaster casts. It is becom-ing increasingly evident that more con-sideration must be paid to the role ofthe musculature.' Functional aberra-tions can create severe morphologicaldisturbances of concern to the ortho-dontist. Mastication, though important,is not the sole functional entity. Ofequal or greater importance are thefunctions of deglutition, respiration andspeech. Perverted perioral muscular ac-tivity during swallowing can createsevere ma:oic!iisioiij or makc cxist:r,gmalocclusions more severe. Relativelylittle objective research has been donein this field, but it seems logical thatabnormalities in respiration and speechmay be as important as impropermastication and deglutition by virtueof the muscular forces involved. Speechproblems in particular are of concernto the orthodontist. Whether they arecausative or resultant of the abnormalmorphology conferred by the dentalmalocclusion, the fact remains that a..*Associate attending orthodontist, Children 'YMemorial Hospital ; forinerlr Associate Pro-fessor, Orthodontics and Director of Research,Sorthwestern University Cleft Lip and Pal-ate Institu\te.**Assistant Professor of speech pathologyand Administrator, Northwestern UniversityCleft Lip and Palate Institute; speerh con-sultant,, Children 's Center, St. Francis Hos-pital, Evanston.***Research Associate, Chiltlren 's MemorialHospital.high percentage of orthodontic patientsdo have speech defects. In many in-stances, the parent will say that this isthe reacon that the child is brought forhis initial orthodontic examination.Mouth breathing, hypernasality, andsibilant defects are common sequelaeof the Class 11, Division 1 malocclusion.In congenital cleft palate patients,speech problems are compounded andthe occlusion may or may not be afactor. Because of the difficulty ofstudying normal speech physiology,controversy exists over the relative im-portance of the teeth and investingtissues, palatal contour, lip activity,duction of normal speech sounds. Since1950, a series of cephalometric-roent-genographic studies of normal andcleft palate subjects has been directedby Graber at Northwestern UniversityCleft Lip and Palate Institute. In thepast two years, an extensive study ofbasic normal speech function has beencarried out through the support of theUnited States Public Health ServiceResearch Grant D-405. The project isdesigned to give an objective, descrip-tive analysis of the function of the"normal" velopharyngeal mechanismduring the instant of production ofeach of the various types of consonantsounds in American English. Thepresent report summarizes these pre-vious and presently continuing in-vestigations.In 1950, Williams made a roent-genographic study of vowel sounds inrinlnnhorrrnrrool .,ol.,:..rr -tr ;- th- nFn'C'"y"u'J"5LY' "U'""'5, CLC. 1'1 C1.L yL"-30 Vol. 29, No. 1Palatal Structures31thirty non-cleft individuals betweentwenty-two and thirty-five years ofage.' This was primarily a study ofsoft-tissue physiology during vowel toneproduction, similar to the study done in1927 and reported by Dr. G. 0. Russellin 1931." With improved roentgeno-graphic equipment, finer analysis ofsoft tissue movements was possible. Henoted that the function of the velo-pharyngeal valve is related directly totongue function. During the produc-tion of the prolonged vowel tones,Williams failed to find any compensa-tory pharyngeal activity. That is, theposition of the posterior pharyngealwall remained relatively stable at restand during function. In 1953, Car-penter reported his study of twelvecleft palate patients ranging in agefrom fifteen to thirty-nine years.* Thesewere postoperative subjects with fairlygood speech and slightly nasal voicequalities. He repeated the study ofWilliams. In addition, he added theconsonant k and had each patient blowinto the calibrated manometer tube.The level of air pressure was recordedfor each test element. Carpenter foundsignificantly more anterior movementof the pharyngeal wall during pro-duction of the consonant sound k, andhe noted some anterior movement ofthe posterior pharyngeal wall in thecleft palate cases during vowel produc-tion that was not present in the normalsample.In 1954, Wildman did a detailedmetric analysis of a velopharyngealclosure and correlated this directly withnasal emission, as measured on aspecially constructed nasometer em-ploying a Marey tamb~ur.~ Nasal emis-sion was highly correlated with thesize of the pharyngeal port. The studycorroborated Carpenter's observationsof compensatory movement of theposterior pharyngeal wall in cleft palatesubjects. Wildman observed a differ-ence in tongue and palate position andthe extent of posterior movement of thesoft palate in cleft palate subjects,when compared with the normal pro-file roentgenograms in Williams' study.In 1951, McDonald and KoeppBaker had reported a tendency in cleftpalate patients to talk with the dorsumof the tongue held high in the back ofthe mouth.'j They expressed the beliefthat this was a major cause of hyper-nasality, nasal emission, and faulty ar-ticulation, and that the elevatedmandible and the malposed tonguewere part of this subnormal functionalactivity. Objective investigation wasdone by McKee to test this thesis andwas reported in 1955.7 McKee notedthat the tongue position was lower thannormal in cleft palate patients. Duringphonation, these patients elicited adefinite posterior movement not foundin comparable normals. McKee's in-vestigation also showed greater extentof movement of the hyoid bone duringproduction of speech sounds. JoSubtelny further corroborated thefindings of McKee on the lack of thehighriding tongue in a more detailedstudy.' In 1956, Senty, using the newstereocephalostat and a high speedrotating anode radiation source, obtain-ed under the United States PublicHealth Grant D-280, studied for thefirst time short duration speech soundssuch as p and k." His analysis of thespeech function of seventeen normalspeech subjects pointed out the im-portance of the adenoid tissue as a fac-tor in velopharyngeal function. Withthis improved methodology, he wasable to show anterior movement of theposterior pharyngeal wall even in nor-mal subjects. The frequency of anteriormovement was correlated with thesounds being produced and the intensityof the sounds.Jn 1957, companion studies byAnderson'O and Nohrstromll comparedsoft tissue changes during speech andswallowing functions for cleft palate 32GraberJanuary, 1959and for normal subjects. Their in-vestigations showed that the degreeand even the mode of velopharyngealvalving was significantly different fordeglutition, as compared with speech.The peristaltic-like action during theact of swallowing for both the normaland cleft palate subjects showed aconstant and maximal activity of thetongue, soft palate and associatedstructures. A much more refined levelof muscle specificity was involved inthe speech act in both subjects. A sig-nificant finding was the fact that somevela, inadequate to supply velopharyn-geal valving for speech in cleft palatesubjects, showed adequate closure dur-ing the swallowing act.This series of studies indicates theneed for a more detailed and limitedinvestigation of the many variables withthe use of the new and improved roent-genographic equipment now available.The following is a preliminary reportof such a study now underway at thePalate Institute.North-,.;esterx LTni~~ersipy Clef: Lip 2ndPRESENT STUDYThe purpose of the present in-vestigation is to objectively describe andanalyze the function of the velopharyn-geal mechanism during the instant ofproduction of each of various types ofconsonant sounds.A method was developed through aseries of preliminary studies on normalsubjects using high-speed, fine-focusroentgenographic equipment modifiedby an instantaneous timer switch andspecial patient-positioning devices. Afterthe methodology and research planhad been developed and tested througha series of fifty pilot investigations oneach of the consonant sounds in Amer-ican English, this second phase studywas initiated. It was limited to the in-vestigation of the velopharyngeal func-tion during the instant of productionof the labial sounds p, b, f, w, and m,since the pilot studies had indicatedthat the most consistently reliable re-sult could be obtained on these sounds.The purpose of this second phase in-vestigation was to describe functionaland morphological changes of the softpalate and related structures from restposition to the instant of production ofeach of these sounds. The second phasestudy sample was made up of forty-four young adult subjects from nine-teen to thirty-five years of age. Eachsubject had normal articulation pat-terns for speech and normal voicequality. Twenty-two of the subjectswere male and twenty-two were female.All were college students enrolled atNorthwestern University at Evanston orLoyola University, Chicago.PROCEDUREAfter preliminary speech, hearing,and voice tests each subject was posi-tioned in a head-holder designed tostandardize all technical variables, totest run and to permit accurate duplica-tion for cross-sectional and longitudinalstudies. A Lyshholm-Schoenander po-larizing grid and a one and one halfmillimeter aluminum filtration screenwere used to improve soft tissue dis-closure and to give added protection tothe subjects. Six exposures were takenon each subject in the series, one forthe rest position, and one each for theinstant of production of the constantsounds p, b, f, w, and m. Each ex-posure was taken at a speed of 1/20of a second at 200 milliamps, and 95Kvp. Ionization chamber tests in-dicated .075 to .090 roentgens per testsound which is far below evenminimal hazard conditions. Soft tissuevisualization was improved throughthe use of a barium disclosing solutionpainted on the lips and tongue of eachsubject. (Figure 1)Certain additional controls were usedin order to eliminate other possible~!i~~inate r~~~!~iii iii~vement du~iiig the Vol. 29. No. IPalatal Structures33Fig. 1eous exposure mechanism.Stereocephaloutnt, using high speed rotating anode radiation source and instantan-variables in the production of thespeech sounds. A standard carrierphrase "Now I say the word" was usedin each case followed by a nonsensesyllable initiated with the test sound.In order to eliminate the possible ef-fect of the vowel tone upon the palatalposition of the consonant sound tested,four different vowel sounds were usedafter the test sounds. The vowelsselected for this purpose were e as inthe word .see, a as in the word father,a as in the word caught, and 00 as inthe word nezo. In order to control pos-sible differences in the force of thespeaker's voice, an Altec 660B micro-phone attached to a PT-6 Magnicorderhi-fidelity tape reproduction system wasplaced exactly six inches from the lipsof each subject. (Figure 2) Each sub-ject monitored the force of his voiceso that a VUmeter on the recorderpeaked at -3 on the test syllable. Eachsubject repeated the carrier phrase andtest syllable three times, monitoringthe force of their voices. The exposurewas timed to coincide with the liparticulation of the consonant sound be-ing tested. Tape recordings were madeof the entire procedure and each sub-ject, and were played back to double-check the timing of each exposure. Thiswas possible because the sound of thecathode-ray discharge was audible onthe tape. Cases with imperfect timingwere eliminated from the study se-quence.The salient structures were traceddirectly on the headplate by each in-vestigator. Following this, superimposed Craber34Fig. 2 Subject positioned by calibratedfidelity Altcv 66OR mici~ophone is mountedexictly six i~lvhes f~on1 the iips at rest.c,. . -ids . :uiil urbitale Innrkers. The higli-tracings of all test exposures were made.(Figure 3) Different colors were usedfor each test sound to prevent con-fusion in interpretation. Accuratemillimetric measurements were madeof the outline of the velum along thesuperior border, from the posteriornasal spinc to the uvula. The velumwas divided into quadrants for all trac-ings. Posterior pharyngeal wall con-tiguent structures were outlined.Specific measurements were made ofthe length of contact of the pharyngealwall and the velum and of the extentof forward movement of the sphinctercomplex. The height of the velum dur-ing function was determined withreference to the palatal plane. Datawere compiled on master charts andsubjected to biometric analysis in anattempt to answer the following ques-tions :1.2.3.1..5.6.7.8.9.January, 1959How long was the palate atphyciologic rest and what changesoccur in palatal length duringfunction?Which quadrant of the palate mostconsistently contacts the posteriorwall during velopharyngeal valv-ing for speech?What is the length of upward andbackward movement of the palateat each quadrant and at whichquadrant does the greatest extentof movement take place?How high does the soft palaterise during speech?What is the midpoint of closureof the velopharyngeal valve?What is the consistency of com-plete or incomplete valving for thevarious test sounds?What is the superior-inferior ex-tent of contact of the velum andposterior pharyngeal wall at themoment of contact?With what frequency does for-pharyngeal wall take place?Is there a consistency to themorphology of these structuresduring speech or is there a differ-ence for each of the test sounds?DATA AND INTERPRETATION.. ."..A mnrmmnntVVLI'U **1"1CII.C.'C Gf the pesterierWith regard to changes in the lengthof the palate from rest to functionalpositions for speech, Figure 4 shows thefindings for the forty-four cases in thisinvestigation. It is obvious from thisfigure that there is a significant in-crease in the length of the palate fromrest to the functional position. AsFigure 4 illustrates, the length of thepalate at rest ranges from 32 to 49 mm.In contrast, the range for the p, 6, andf sounds which, by their nature re-quire the firmest velopharyngeal clo-sure, was from 45 to 70 mm. In thestudy sample, Case Three and CaseForty-two illustrate the extremechanges in palatal length from. rest to Vol. 29. No. 1 Palatal Structures 35bW?OblTL kAClMe %WWMETHOD OF QUADRANT ANALYWSFig. 3 Typic31 cephaloiiietric lateral t.incing sliowiiig p;il:it:ll, tongue, pnstpIi:~~yig~%l ~::ll,mandibular and hyoid bone positions for each of llie six test. elrinent,s. Tllr superior surf:lrc.of the soft palate has been divided into qu:idrants to permit :I move tlrtiiiitivc stnfl!. ofpalatal function.functional position. At rest, the palateof Case Three measured 32 mm. inlength. In function, on the p and bsounds, the same palate measured 57mm. In Case Forty-two, the palatewhich measured 32 mm. at rest, chang-ed to a length of 62 mm. on a p soundand 63 mm. on the b sound. In all case,the changer. in length for the p, b, andf sounds were closely similar. Changesin length on the UJ sound were alsosimilar but tended to be somewhat lessthan for the other three sounds. Ofsignificance was the increase in palatallength found during the production ofthe m sound. Although the m soundis made by emitting air through thevelopharyngeal port, the palate does as-sume a close-ready position of closurewhich is actually more similar to closedposition than the rest position. Thisfact is objectively substantiated by thisand other measurement findings. Thesemeasurement changes in length are notinterpreted as meaning actual in-cremental increase, but rather as evi-dence of the incorporation of tissueelements from the lateral pharyngealwalls.A highly significant finding resultedfrom the measurement of the quadrantof contact of the palate with the post-pharyngeal wall during speech func-tion. Although in the past it has gener-ally been assumed to be the middlethird of the palate which effects thevelopharyngeal seal, this evidenceshowed conclusively that for youngadults it is the third quadrant whicheffects this seal. The third quadrantwas involved in the seal in 100% ofthe cases for the study sample. Quad- 36Craber January, 1959I814-18-P8F---- .-. -.. .. . .. . . ... .Fig. 4gr:ipIi. Note the significant increase in palatal length for all test sounds.The resting lengtlis and funetional increments for all cases are plotted on thisrant four was also involved in the sealin 27f? of the cases. Figure 4 illustratestypical quadrant division in contactfound in the study.Table 1 shows the findings regard-ing the extent of upward and backwardmovement of the palate at each of thequadrants measured. A consistent find-ing in this data indicates that Q2, themidpoint of the palate, shows the great-est extent of upward and backwardmovement from rest to closed position.Despite the magnitude of movement atQ2, the region of the midpoint of thepalate was not involved in actual con-tact with the posterior pharyngeal wall.The second most extensive upward andbackward movement was found in Q3,which was involved regularly withvelopharyngeal seal. A wide range ofangular measurements was found il-lustrating the direction of movement ofthe palate of each subject. Table 2lists the angles described by the inter-section of Line Q2 at the palatal plane.The wide range of measurements maybe attributed to individual differencesof cranio-facial morphology. In allcases, direction of movement was up-ward and backward. Vol. 29, No. 1 Palatal Structures 37EXTENT IN MM OF UPWARD BACKWARDMOVWhlRNT OF TIlE SOFT PALATEQwrlrant Phonatioii Xean S.D. RangeQ1. ....... P 6.0 2.06 3.0- 9.0Q1 ........ B 6.1 2.25 3.0-10.0Ql.. ...... F 6.0 2.35 2.0-10.0Ql.. ...... PRF 6.0 2.22 2.0-10.0 I.. ...... If 3.9 2.03 1.0- 8.0Ql.. ...... W 5.8 2.56 2.0- 9.0Q2 ........ P 16.2 3.41Q2 ........ B 16.2 3.40Q2.. ...... F 16.2 3.01Q2 ........ PBF 16.2 3.27Q2. ....... W 1.5.4 3.18Q2. ....... 11 10.2 3.01Q3 ........ P 14.2 3.42Q3. ....... B 14.1 3.02Q3.. ...... F 13.7 2.81Q3.. ...... PBF 14.0 3.10Q3 ........ W 13.6 3.61Q3.. ...... M 9.7 3.3810.0-27.09.0-23.09.0-23.08.0-27.08.0 - 2 2.02.0-17.07.0-20.08.0-20.06.0-19.06.0-20.06.0-20.02.0 - 17.0Q4.. ...... P 10.0 3.77 2.0-19.0Q4.. ...... B 10.0 3.38 4.0-16.0Q4.. ...... F 9.6 3.23 3.0-16.0~4.. ...... xr 6.7 3.32 1.0-13.0Q4.. ...... PRF 9.9 3.46 2.0-19.0`44.. ...... W 9.5 3.15 3.0-17.0Table I The gre.Ltest upward and back-ward movement occurs at Q2, or the mid-point of the superior palatal surface. Move-ment at Q3 was only slightly less, but uni-formly contacted the pwtpharyngeal wall.Figure 5 shows the findings regard-ing the high point of the soft palateduring speech and the midpoint ofclosure. It is significant that in allANGLE DESCRIBED BY MID-POINTOF PALATE IN FUNCTIONPhonatbn, Mmv. S.D. Range Mode NumberP ... 56.0 5.68 26-76 52 42R . . 52.6 5.07 24-73 58 44F . . 52.8 5.09 23-71 58 44W . . 51.6 2.69 23-73 48 44If . . 44.2 2.44 27-66 41 43Table 2 Quadrant markings at rest andduring phonation for each sound were joined.The intersection of these lines with thepalatal plane formed the recorded angles.The relatively smnll standard deviations forw and m suggest greater constancy of posi-tion for these consonants, but the broadranges reduce the significance of any inter-pretation.sounds, particularly the nasal, the highpoint was above the level of the floorof the nasal cavity. The same figureshows that the midpoint of closure issomewhat below the level of thepalatal plane, but the high point ofthe actual seal in most cases approx-imated the level of the nasal floor.This has clinical implications regardingthe placement of the prosthetic speechbulb and the attachment of the pharyn-geal flap in certain surgical proceduresin cleft palate rehabilitation.The pharyngeal valve was consistent-ly closed for the consonants p, b, f, andw. This finding is at variance with otherstudies, using more static roent-genographic techniques.The superior-inferior extent of con-HIGH-POINT:1 /+-J-I pT7T COYUrnD-2-3j -4 LMID901Nf-54-7HIW-~INT a MIPPOINT OF RLATAL CLOSUREFig. 5 The higheet point of palatal eleva-tion (Q2) was consistently above the floorof the nasal cavity. The midpoint of velo-pharyngeal valving waa 2.4 mn~ below thenaeal cavity floor. This is higher than gen-erally described, 38 Craber January, 1959~~PA . . 8.94 3.93 2.0-17.0 42RA . . 9.8; 3.96 3.6-20.0 42I!'.\ . . . 1 l.O(i 4.43 4.0-21.0 41WA . . 10.40 4.48 3.8-18.0 40Tabla 3 1':ilatal yostpli:rryngc::l wtll COII-tiguitg during eonnon:int phonation.tact on these sounds ranged from 2 to21 mm. Table 3 shows the range, meanand standard deviation for the sample.Despite the broad range, there is arelatively narrow standard deviationand closely similar mean length of con-tact for different test sounds.The posterior pharyngeal wall movesforward in more than 50% of the cases.Dramatic constrictor activity assistingin normal velopharyngeal valving wasobserved in at least four patients.Figure 6 is an example of extremeanterior movement of the so-called"Passavants pad". These findings wereinterpreted as indicating that, at leastin some cases, normal velopharyngealvalving was assisted by significant,superior constrictor activity. However,in the majority of these cases, theanterior component was minimal.From observation of the consecutiveheadplates on each individual case, it isobvious that a high degree of con-sistency of morphology of the velopha-ryngeal structures is found during theact of speech. There appear to be vary-ing soft tissue contours from case tocase, but, despite this, precise measure-ments of thc valving act, as reportedabove, show a close similarity for allcases. SUMMARY AND CONCLUSIONSA review was given of the series ofrelated research studies on speechFig. 6 Dramatic " Passavant's pad'' activity, white female, with nornial speech. Thisanterior bulging of the postpharyngeal wall was evident. for all test exercises in this subject. Vol. 29, No. 1 Palatal Structures 39physiology carried on by the North-western University Cleft Lip and PalateInstitute. In general, these studies in-dicated that anterior movement of thepozterior pharyngeal wall is more com-mon in cleft palate than in normalsubjects during the production ofspeech sounds. Studies involving con-sonant sound elements did show somepharyngeal activity even for normalsubjects. It was objectively establishedthat nasal emission and hypernasalitywere highly correlated with the sizeof the velopharyngeal port. Aberranttongue position in function was notedin the cleft palate cases. Metric analysisshowed that tongue position was ac-tually lower in the cleft palate than inthe normal subjects. The principalvariation from normal activity in thetongue function of cleft palate patientswas in the nature of a posterior posi-tioning. Other studies showed a sig-nificant difference in velar valving fordeglutition as compared with speech.A research study based upon thesepreviouq investigation., was outlined.Using high speed roentgenographicequipment, the soft tissue morphologyof normal subiects was studied duringthe instant of production of variousconsonant sounds (p, b, f, w, m). Bio-metric analysis was made of the roent-genographic findings and the followingconclusions were drawn : the soft palateincreases significantlv in length fromthe rest to functional position. It is thethird quadrant of the palate which con-sistently effects the velopharynyeal sealfor normal young adults. The greatestextent of the upward and backwardmovement of the palate takes place atthe midpoint of the posterior superiorsurface of the palate. The mean ex-tent of movement at this point is ap-proximately 16 mm. The high pointof the soft palate is consistentlv foundto be 4 to 5 mm. above the level ofthe palatal plane during valving. Forthe nasal sound "m", the high pointwas found to be 3 to 4 mm. higher thanfor the remaining consonant testelements. The high point of the softpalate was never' involved in actualvelopharyngeal seal. The midpoint ofclosure during velopharyngeal seal isno-mdly 3 to 4. mm. below the palatalplane. The high point of seal is foundapproximately at the level of the palatalplane. The velopharyngeal valve is con-sistently closed for all of the con-sonant sounds during normal speechproduction. The palate assumes a closeready position of velopharyngeal closureeven for' the nasal soxnds. Slight anter-ior movement of the po2terior pharyn-geal wall is seen in over 50% of thenormal cases. Dramatic anterior move-ment occasionally occurs in normal sub-jects. Metric analyses ehow that thereis a con tent pattern of velopharyn-geal valvinq for speech for normal sub-jects.The orthodontist, as well as the.prosthodontist and speech therapist,should profit from P bcttrr appreciationof normal speech physiology.450 Green Bay RoadKmilrr~orth, Zl1inoi.rBIBLIOGRAPHY1. Grzber, T. M.: Extrinsic Factors Am..7. Orlko., 44: 26-45, .Tamiiry, 19.511.2. Williams. Robert A.: A Serial Radio-graphic. Study of Velophanwgeal Clos-we and Tongue Pasitim iii CertaiiiVowel Souiids. Zmfer's T1iPni.v. North-western University, 1951.3. Ru~sell, G. 0.: Spew11 :III~ Voice, Macs-Millan 8; Conipaiiy, Ncw Pork: 1931.4. Cnrpeib'er, Chzrles: A Serial Radiographic St,udy of the Functioual Chaiiges ofthe Soft Palat? and NnsoDharynx Dur-5.inq Phonation of Certain Vokds andConsonants in Operated Cleft PahtePztients. Mn.vtrr '8 Thesis. NorthwcsternUniversity, 1953.Wildman, J. Alexander: A Study ofthe Relet,ion Between Nasal Emissionand the Form and Function of CertainStrnrtnres Associated with Nasopharyn- 40 Craber January, 1959geal Closure in Cleft Palate Individuals. Nasometric Study of NasopharyngealMaster's Thesis. Northwestern Univer Efficiency in Normal Individuals Dur-sity, 1954. ing the Production of Certain Speech6. McDonald, E. T., and Baker, H. Koepp: Sounds. Vaster's Thesis, NorthwesternCleft Palate Speech: Integmtion of Re- University, 1956.search and Clinical ObserT'ation, J. 10. Anderson, Barrett : A Functional Radio-Speech amd Hearing Disorders, 16 : 9-20, graphic Investigation of the Nasal andMarch, 1951. Oral Pharyngeal Structures During7. McKee, Larry: A Cephalometric Radio- Deglutition in Cleft Palate Individuals.graphic Study of Tongue Position in Master's Thesis, Korthwestern Unirer-Individuals with Cleft Palate. Master's sity, 1957.8. Subtelny, Jo Ann: Laminagraphic Study alometric Radiographic Investigation ofof Nasolingual Vowels Produced by the Nasal and Oral Pharyngeal Struc-Cleft Palate Children. Ph.D. Thesis. tures During Deglutition in Non-CleftNorthwestern University, 1956. Palate Individuals, Master's Thesis,Thesis, Northwestern 1955. ] 1. No}lrstrom, pirkho: A finctional Cepll.9. Senty, Edmund L. : A Radiographic andSorthwestern University, 1957.