Anatomical Characteristics of Palatoglossus and the Anterior Faucial Pillar

DAVID P. KUEHN, Ph.D. NABIL A. AZZAM, Ph.D. Iowa City, Iowa 52242

Palatoglossus and the anterior faucial pillar were studied using three techniques: 1) gross dissection, 2) radiographic filming, and 3) histological sectioning. The total subject sample included 25 normal adult male and female cadavers. Palatoglossus has a flattened belly within the faucial pillar, a fan-shaped termination within the palate, and a vertical tapering termination within the . The region of attachment into the palate differs among individuals which could influence its relative importance in velar versus lingual movement. The pillar contains a large investment of loose connective tissue whlch also penetrates palatoglossus. The collagenous framework would apparently allow expansion of the pillars but also prevent rupture of the tissue at extreme extension. The anterior portion of the pillar contains a sheath of elastic fibers with a density gradient increasing from the tongue to the . The elastic fibers, which also intermingle with palatoglossus fascicles, could provide a restorative force in lowering the palate, helping to keep the nasopharyngeal airway patent.

Palatoglossus is classified as a muscle of the atoglossus, few details about its morphology soft palate in the 1968 Nomina Anatomica have been provided (Dickson et al., 1974). For although some authors describe it in relation example, its size has not been well-docu- to the lingual muscles. The classification is mented. Luschka (1868) reported that pala- somewhat arbitrary since the muscle attaches toglossus is only 1.5 and 3 mm in its narrow to both movable structures. However, as and wide diameters at the level of the anterior pointed out by Crouch (1972), its embryo- faucial pillar. However, according to Hoeve's logical origin and innervation are more simi- (1910) manual of dissection, palatoglossus is lar to those of the palatal muscles. The lingual 13 mm in diameter and is cylindrically muscles receive their innervation from the shaped. Reports regarding the size of palato- hypoglossal and the palatal muscles glossus in cleft palate individuals also are excluding tensor veli palatini, are supplied disparate. Veau (1931) and later Kriens through the pharyngeal plexus. (1975) found palatoglossus to be extremely Although there is general agreement con- hypoplastic in cleft palate newborns. In con- cerning the anatomical characteristics of pal- trast, Fara and Dvorak (1970) reported "com- paratively good development" of palatoglos- sus in relation to other palatal muscles in 18 Dr. David P. Kuehn is Associate Research Scientist, Department of Otolaryngology and Maxillofacial Sur- stillborn children with cleft palate. gery, University of Iowa, Iowa City, IA 52242. Dr. Az- Palatoglossus is in a position to lower the zam, who has been Associate Professor, Department of palate, elevate the tongue dorsum, and con- Anatomy, College of Medicine, University of Iowa, is strict the anterior faucial pillars. It is generally currently Professor of Anatomy, Department of Human Morphology and Experimental Pathology, Faculty of agreed that tongue elevation and constriction Medicine, Kuwait University, Kuwait. of the helps to propel the bolus of food A paper and poster based on this study were presented toward the esophagus during . at the Third International Congress on Cleft Palate and - This activity also tends to occlude the oral Related Craniofacial Anomalies, Toronto, Canada 1977. cavity thus preventing retrograde flow. How- This project was supported in part by PHS Research Grant DE-00853, The National Institute of Dental Re- ever, such action may not occur in those cleft search. palate and normal individuals who utilize the 349 350 _ Cleft Palate Journal, October 1978, Vol. 15 No. 4 so-called "free fall" mechanism of swallowing sible to provide a medial-to-lateral dissection (Flowers and Morris, 1973). » approach. In this approach, the anterior fau- The function of palatoglossus during speech cial pillar was easily accessible (Figure 1). The has not yet been resolved. Electromyographic mucous membrane and submucous fascia of activity recorded from palatoglossus in asso- the anterior faucial pillar were removed with ciation with velar and lingual movements relative ease exposing the palatoglossus mus- varies between speakers (Fritzell, 1969; Lub- cle (Figure 2). (The muscle attachments were ker et al., 1970; Lubker and May, 1973; Bell- dissected after the second phase had been Berti, 1976; Benguerel et al., 1977). As pointed completed). The widest diameter of the mus- out by Bell-Berti (1976) it is not known cle was measured with a caliper midway be- whether such variation is due to idiosyncratic tween the tongue and soft palate. Levator veli behavioral differences or to anatomical fac- palatini also was exposed with dissection ex- tors. ' tending as close to the origin and insertion as The anterior faucial pillar has received lit- possible without damaging or displacing the tle attention in the literature in spite of the attachments. The levator diameter also was fact that it is the site of a common surgical measured to provide a comparison with that procedure, tonsillectomy. Even with present of palatoglossus. The measurement was made day surgical techniques the anterior faucial in the region of the auditory tube orifice after pillar is invaded in some cases which undoubt- torus tubarius had been removed. It should edly injures palatoglossus and causes consid- be pointed out that these measurements may erable scarring (B.F. McCabe, personal com- deviate somewhat from muscle size in vivo munication). Tissue contracture due to scar- due to fixation artifacts. ring might be expected to constrain velar The second phase of the study provided an elevation in these cases. However, speech indication of possible force vectors of palato- problems apparently have not been docu- glossus and levator relative to the soft palate. mented in relation specifically to the effects Radiographic filming was utilized and in- of this surgical trauma. volved wrapping the midportion of palato- The purpose of the present study is to pro- glossus and levator with a radiopaque thin vide additional information concerning the metal foil (Dryfoil) to enable visualization of anatomy of palatoglossus and its surrounding the muscles. A blunt-end thumb forceps was anterior faucial pillar, all of which is necessary used to guide the foil through the bed which to clarify the uncertainties and conflicts re- lay deep to each muscle. The foil was then lated to the configuration and function of the folded securely around the muscle belly. The muscle-pillar complex. muscle was not displaced during this proce- dure and the muscle attachments were left Procedure intact. Hemisections from nine cadavers were The sample included 25 heads from adult x-rayed in lateral, frontal, and basal projec- human male and female cadavers represent- tions using a cephalostat. ative of the fifth, sixth, or seventh decades at In four of the specimens, the jaw opening the time of death. They were selected from appeared to be unnaturally large. The x-ray bodies donated to the University of Iowa for films were repeated for these specimens with medical research. Available medical histories the jaw in a more closed position. Lateral indicated no gross orofacial pathologies and radiographs showed that a closer jaw position none of the subjects had undergone tonsillec- had no effect on levator position but changed tomy. This was verified by both investigators the orientation of palatoglossus. Since the pal- during dissection. atoglossus muscle attachments were intact, The study was conducted in three phases. raising the jaw, which also raised the tongue, The first phase consisted of gross dissection of decreased the angle formed by palatoglossus fourteen cadaver heads which were sectioned and the hard palate. That is, the angle be- parasagittally as close to the midline as pos- came more acute. The third or histologic phase involved sec- ' Professor and Head, Department of Otolaryngology tioning of undissected blocks of tissue from and Maxillofacial Surgery, University of Iowa. eleven cadavers. These blocks consisted of the Kuehn, Azzam, PALATOGLOSSUS AND FAUCIAL PII LAR 351

FIGURE |. Parasagittal section showing the undissected anterior faucial pillar (arrow) bulging into the oral cavity. Tongue (T); Hard Palate (HP). entire anterior faucial pillar with lingual and Results palatal tags attached. However, because of the excessively large size of the blocks other- Macroscopic OrservaTIons. The anterior wise required, the lingual and palatal tags faucial pillar was well-defined in all speci- were not extended to the midline. The tissue mens. The bulge which projected medially blocks were post-fixed in 10 per cent formalin coursed between the soft palate and tongue prior to paraffin embedding and sectioning. (Figure 1). After removing the mucous mem- Serial sections at 15 um intervals proceeded brane, palatoglossus was found to have a flat- superiorly into the soft palate and inferiorly tened belly within the anterior faucial pillar. into the tongue. Thus, transverse sections were In most specimens, a substantial investment obtained in the soft palate and tongue por- of connective tissue was noted within the mus- tions as well as the anterior faucial pillar. cle itself as well as within the surrounding A spectrum of histological detail was visu- tissue of the anterior faucial pillar. The muscle alized by using: 1) hematoxylin-eosin (H & E) portion within the anterior faucial pillar was for general histology, 2) periodic acid-Schiff found to have fairly uniform dimensions (PAS) for staining salivary glands, 3) Mallory along its length (Figure 2). Table 1 compares triple stain (MTS) for differentiating muscle the diameters of palatoglossus and levator veli from connective tissue, and 4) Verhoeff - Van palatini muscles and shows that palatoglossus Gieson method (VVG) for differentiating col- is a much smaller muscle than levator aver- lagenous fibers from elastic fibers. Each sec- aging less than 5 mm in diameter, only about tion of a series was stained with one of the half that of levator. The widest dimension was above methods in consecutive groups of four. oriented obliquely but primarily anterior-to- This procedure provided a means of following posterior in most specimens. In four of the muscle fascicles, salivary glands, and connec- fourteen specimens dissected the widest di- tive tissue elements from the attachment in mension was in a more medial-to-lateral ori- the palate through the anterior faucial pillar entation. to the termination in the tongue. A fan-shaped termination within the soft 352 Cleft Palate Journal, October 1978, Vol. 15 No. 4

FIGURE 2. Parasagittal section showing palatoglossus (arrow) after removal of overlying mucous membrane and submucous fascia. Portions of the tongue (T) and soft palate (SP) have been removed for better visualization of palatoglossus. The hard palate (HP) also is indicated. palate was observed in all specimens. Muscle position. The configuration shown in Figure fibers began diverging at the most superior 3B is quite different. In this specimen, the level of the anterior faucial pillar. At this potential force vector for palatoglossus is di- point, the fibers were rather superficial as they rected much more inferiorly and posteriorly, were throughout the length of the anterior toward the uvula. Again, this was true faucial pillar. More medially, the muscle fas- whether the jaw was in an open or closed cicles were found to spread and proceed su- position. Lateral radiographs of six of the nine periorly away from the oral surface of the soft hemisections exhibited a relationship among palate. Fiber termination within the tongue palatoglossus, levator, and the soft palate sim- was very difficult to follow beneath the lin- ilar to that shown in Figure 3B, whereas the gual surface using gross dissection. The pala- remaining three were similar to that of Figure toglossus muscle was consistently anchored 3A. The size of palatoglossus did not appear firmly at the point of entry to the tongue. to be systematically related to the particular Lateral radiographs indicated that poten- anatomical arrangement. tial force vectors of palatoglossus in relation Microscoric OmseErvations. Histological to the tongue and soft palate varied for dif- sections stained with H & E, MTS, and VVG ferent specimens. The configuration shown in provided detailed information concerning the Figure 3A was expected on the basis of text- course and terminations of palatoglossus. A book drawings of the region (for example, cross-section through the middle of the ante- Woodburne, 1973). Specifically, the lines of rior faucial pillar is illustrated in Figure 4. At potential force for palatoglossus and levator this level, palatoglossus is in close proximity are directed toward each other in the soft to the much larger tongue elevator, stylo- palate, independent of the open or closed jaw glossus. fascicles in the

Kuehn, Azzam, PALATOGLOSSUS AND FAUCIAL PILLAR 353

TABLE 1. Diameters in millimeters of palatoglossus shaped membrane resulting in an inferiorly- and muscles.* directed tapering insertion in the laterodorsal

Palatoglossus Levator aspects of the tongue. This is contrary to Specimen many textbook descriptions which indicate left right -_ left right that palatoglossus blends with muscles of the M1 6.2 5.2 9.2 10.9 tongue. M2 3.8 4.1 6.0 6.1 Using the PAS method to enhance visual- M3 5.5 5.8 7.8 8.3 ization of the mucous glands, an abundance M4 3.6 4.1 8.5 11.6 of submucosal glandular tissue was found lin- M5 5.0 2.0 9.5 9.2 ing the oral surface of the soft palate which M6 4.0 - 9.6 - M7 4.9 - 11.4 -- agrees with most textbook descriptions of this M8 3.7 - - - region. Mucous glands also were found within M9 3.2 3.4 5.8 5.9 the anterior faucial pillar between palatoglos- M10 - - 9.4 9.2 sus, , and stylopharyngeus muscles F1 5.6 4.8 6.2 6.9 (Figure 4). The presence and wide distribu- F2 ‘ 4.3) - 8.3 - tion of these glands were consistent in all the F3 - 3.2 - 7.8 specimens studied. F4 - 3.1 - 5.5 MTS staining showed a surprisingly large S.D. 0.97 1.18 1.76 2.10 proportion of connective tissue elements in Mean 4.53 3.97 8.34 8.14 relation to muscle for ten of the eleven speci- * Palatoglossus was measured midway between the mens sectioned. The anterior faucial pillar is tongue and soft palate. Levator was measured in an area subject to frequent strain during speech and deep to torus tubarius M and F designate sex of speci- swallowing and there is need to restore the men. A periodontal cyst was observed just anterior to palatoglossus in Subject M1O; accordingly, the muscle structure to its resting configuration. A ques- was not measured. tion thus arose as to the composition of the connective tissue elements. A restorative force could be provided by elastic fibers if they are anterior faucial pillar are rather loosely ar- present in the connective tissue. VVG staining ranged with a considerable amount of con- for elastic fibers was used to determine nective tissue interspersed and surrounding whether such fibers exist in the anterior fau- the whole muscle (Figure 4). With the H & E cial pillar. Elastic fibers were found in a con- method the superficial muscle fibers stained centrated sheath in the anterior portion of the darker (more eosinophilic) than the deeper anterior faucial pillar (Figures 4 and 7). The fibers. right portion of Figure 7 shows that the elastic At the level of the soft palate, palatoglossus fibers are kinked and rather loosely-arranged fascicles diverged from the central band of the within the anterior faucial pillar. Because of muscle resulting in a fan-shaped termination this arrangement, the individual fibers varied (Figure 5). The muscle fascicles pass medially in their directionality. However, serial sec- and intermingle with mucous glands and tions clearly indicated that the fibers collec- loose connective tissue lying deep to the mu- tively form a well-defined layer that extends cosa. It was not possible to follow the fascicles from the tongue to the soft palate in the all the way to the midline in the soft palate anterior region of the anterior faucial pillar. due to the limited block size. Therefore, the The elastic layer follows the contour of the description in most anatomy texts indicating anterior faucial pillar. That is, between the that palatoglossus fibers in the soft palate are soft palate and tongue, it has primarily a continuous with those of the opposite side vertical orientation. As the anterior faucial could not be evaluated. pillar blends into the soft palate, the elastic Figure 6, a representative cross-section, layer assumes a transverse orientation which shows the terminal fascicles of palatoglossus is just deep to the oral mucous membrane. within the tongue. Observations of serial sec- The elastic layer was found to have a quan- tions in this region indicated that palatoglos- titative density gradient that increases from sus fascicles are cohesive in the tongue and the tongue to the soft palate. are surrounded by a fascial sheath. These Elastic fibers were interspersed among the fibers gradually terminate along this funnel- palatoglossus muscle fascicles but not within 354 Cleft Palate Journal, October 1978, Vol. 15 No. 4

FIGURES 3A and B. Lateral-view radiographs of two different cadaver hemisections showing relationship between palatoglossus (bottom arrow in each x-ray) and levator veli palatini (top arrow in each x-ray). Muscle fiber direction within each bundle is approximately perpendicular to corresponding arrow. Muscle attachments were left intact. Radiopaque thin metal foil was wrapped around the midportion of each muscle to accentuate its course.

styloglossus, the adjacent muscle (Figure 8). bundles that were arranged perpendicular to Figure 9 shows two types of elastic fiber pat- the muscle fiber course. The individual elastic terns present just deep to the oral surface of fibers within the soft palate exhibited a lack the soft palate which were dense meshworks of uniform directionality just as in the anterior and more discrete but dense bundles. The faucial pillar. nasal surface of the soft palate also contains a dense layer of elastic fibers (Bloom and Discussion Fawcett, 1975). Some of the muscle fibers of The results generally indicate that palato- palatoglossus appeared to terminate on elastic glossus has a fan-shaped attachment in the - Kuehn, Azzam, PALATOGLOSSUS AND FAUCIAL PILLAR 355

<4

FIGURE 4. Transverse section through the midportion of the anterior faucial pillar. Anterior is bottom of figure, medial to the left. Palatoglossus muscle fascicle (PG), band of elastic fibers (EF), (MG), styloglossus (SG), and stylopharyngeus (SPh) are indicated. MTS X 15.

#1 FIGURE 5. Transverse section within soft palate just superior to the anterior faucial pillar. Palatoglossus muscle fascicles (PG) can be seen diverging from the more central portion (C) of the muscle. Anterior is top of figure, medial to the left. The anterior faucial pillar is lateral to the oral mucous membrane (OMM) which is cut obliquely in region indicated by the arrow. Mucous glands (MG) also are shown. H & E X 25.

356 Cleft Palate Journal, October 1978, Vol. 15 No. 4

fm FIGURE 6. Transverse section through the terminal fascicles of palatoglossus within the tongue. Arrows point to interstitial tissue region surrounding the muscle. VVG X 27.

FIGURE 7. Transverse section (left portion of figure) through the anterior faucial pillar showing band of black- stained elastic fibers (EF) in the anterior region. A portion of the oral mucous membrane (OMM) is shown. Medial is bottom of figure, posterior to the left. VVG X 47. A higher magnification of boxed area is shown at right portion of figure. The blackest elements are elastic fibers (EF). Lighter structures are muscle and collagenous tissue. VVG x 240.

soft palate, courses through loose connective styloglossus because of its relatively small tissue within the anterior faucial pillar, and cross-sectional size and large investment of has a tapering termination in the tongue. It connective tissue. appears that palatoglossus would generate a The biomechanics of tongue elevation ver- much smaller contractile tension than its an- sus velar lowering resulting from or assisted tagonist levator veli palatini and its synergist by palatoglossus contraction would depend,

Kuehn, Azzam, PALATOGLOSSUS AND FAUCIAL PILLAR 357

e

FIGURE 8. Section through palatoglossus (PG) and s tyloglossus (SG). Blackstained elastic fibers intermingling with collagenous fibers (examples shown by arrows) are found among palatoglossus fascicles but not styloglossus. At this level, palatoglossus has begun a transverse course into the soft palate. Antero-medial is to the left of the figure. vVG x95.

FIGURE 9. Transverse section within the soft palate near the oral surface showing dense meshwork (M) and also narrower bundles (B) of elastic fibers. Individual muscle fibers of palatoglossus (PG) may be seen. Anterior is bottom of figure, medial to the left. VVG X 270.

of course, on which structure is relatively fixed velar lowering or perhaps both, also would be by other musculature and which is more free influenced by the location of applied force, to move at any given instant in time. How- that is the place of palatoglossus termination. ever, the movement produced by palatoglos- The region of termination within the tongue sus contraction, whether it is tongue elevation, was fairly constant across specimens. How-

358 Cleft Palate Journal, October 1978, Vol. 15 No. 4 ever, the attachment site in the soft palate surface area expansion of the anterior faucial varied. In most specimens, this region was pillar which is necessary during velar eleva- nearer the uvula than the rim of the hard tion for swallowing and speech. As a result of palate (Figure 3B), a region which is clearly the anterior faucial pillar expansion, the col- not a rigid anchoring point toward which the lagenous fibers presumably would be tongue might be pulled. This suggests a lim- straightened and aligned in the direction of ited mechanical ability for palatoglossus in the applied force. Further expansion or rup- elevating the tongue but favorable in lowering ture of the anterior faucial pillar could be the soft palate, especially if the tongue is prevented by the low extensibility and high relatively stable. In these specimens the pala- tensile strength characteristics of the collage- toglossus-soft palate mechanism could be ca- nous fibers (Chvapil, et al., 1973). tegorized as a Class II lever system in which The anterior faucial pillar and soft palate the load lies between the applied force and could be restored to the resting (palate low- the fulcrum. The load consists of the bulk of ered) configuration on the basis of three the soft palate. The applied force is through forces: muscle contraction, gravity, and tissue palatoglossus and the fulcrum is the posterior elasticity. The presence of elastic fibers in the rim of the hard palate or perhaps the point of soft palate, anterior faucial pillar, and be- levator insertion if this muscle is in a firmly tween palatoglossus fascicles suggests their contracted state. A Class II lever always op- functional utilization in helping to restore the erates with a mechanical advantage, in this palate to the rest position. Lowering the pal- case to lower the palate. This would appear ate by elastic recoil would have the virtue of to be an important mechanism in propelling conservation of muscle effort, would be highly a bolus of food toward the esophagus and automatic, and could also oppose the force of tightly approximating the soft palate and gravity. The latter is an important consider- tongue dorsum during the latter stages of ation in terms of sleeping in the supine posi- swallowing. tion. The effects of gravity in this body posi- For those individuals in whom palatoglos- tion might actually tend to approximate the sus is relatively large and attaches into the an- palate and pharyngeal walls. However, elas- terior portion of the velum (Figure 3A), the ticity of the anterior faucial pillar would tend ability to elevate the tongue would be in- to keep the nasopharyngeal airway patent creased considerably, especially if the velum without the need for continuous muscle con- is stable. In terms of velar lowering, a Class traction. Bloom and Fawcett (1975) reported III lever system exists which involves an ap- that elastic fibers also are present within the plied force between the load (soft palate) and. muscles of the . These fibers could aid the fulcrum (rim of hard palate) and always in maintaining a patent nasopharyngeal air- operates with a mechanical disadvantage. way. It is known that changes in elastic tissue Perhaps in these individuals the primary occur as a function of age which presumably mechanism in approximating the tongue and lead to a decrease in resiliency and a concom- soft palate during deglutition is tongue ele- itant lax condition (Yu and Blumenthal, vation rather than velar lowering. 1967). Such a lax state might possibly con- Electromyographic activity recorded from tribute to mouth breathing and snoring in the palatoglossus has been reported in relation to supine position in older individuals (see also both tongue elevation and velar lowering dur- Boulware, 1969 for theories of snoring). ing speech production in normal speakers and The mechanism of elastic recoil also may also during swallowing (Fritzell, 1969; Lubker be a factor in velar lowering during speech in et al., 1970; Lubker and May, 1973; Bell-Berti, some individuals. In an electromyographic 1976; Benguerel et al., 1977). However, pala- study, Bell-Berti (1976) concluded for three of toglossus apparently is not active in velar her four subjects that "opening of the [velo- lowering in all individuals (Bell-Berti, 1976). pharyngeal] port results from the natural The connective tissue fibers observed tendency of tissue to return to its rest position, within the anterior faucial pillar were not and not from increased activity in any mus- compact and straight as those of tendon. This cle." The finding of elastic fibers in the ante- looser fiber arrangement apparently would be rior faucial pillar lends support to this state- fairly extensible (Harkness, 1968) and allow ment. Kuehn, Azzam, PALATOGLOSSUS AND FAUCIAL PILLAR 359

As stated previously, none of the subjects in 225-240, 1976. this study had undergone a tonsillectomy. It BrencourErEL, A. -P., Hirose, H., SawasHima, M., and UsH1Ijima, T., Velar coarticulation in French: An elec- is possible that although changes occur as a tromyographic study, /. of Phonetics, 5, 159-167, 1977. result of this operation in some cases, such as BHancoo, K. S., and Cnxurcx, J. C. T., Elastogenesis in scarring of the anterior faucial pillar, func- healing wounds in bats, Plast. Reconstr Surg., 57, tional characteristics return to the presurgical 468-479, 1976. state. In this regard, it is known that collagen Broom, W., and FawcEtTT, D. S., A Textbook of Histology (10th Ed.) Philadelphia: Saunders, 601 and 617-618, remodeling may occur over several months 1975. following wounding (Hunter and Finlay, BourwaAre, M. H., The Riddle of Snoring Mokelumne Hill: 1976). Such an extended remodeling process Calif., Health Research, 1969. might be necessary in accommodating the Carrson, B. M., The Regeneration of minced muscles. In Monographs in Developmental Biology (A. Wolsky, ed.), continual stresses normally occurring in the Basel, S. Karger, Vol. 4, 1972. velopharyngeal region. An important require- CHvaPpit, M., KronENTHAL, R. L., and Van WinkEL, W., ment is that the soft palate not be tethered by Medical and surgical applications of collagen, In Inter- the scar tissue. Expansion of the anterior fau- national Review of Connective Tissue Research (D. A. Hall cial pillar area by velar elevation especially in and D. S. Jackson, eds.), N.Y.: Academic Press, Vol. 6, 1-61, 1973. the earlier stages of healing may be helpful in CroucH, J. D., Functional Human Anatomy (2nd Ed.). Phil- permanently elongating otherwise contracted adelphia: Lea and Febiger, 201-202, 1972. scar tissue (Arem and Madden, 1976). If the Dickson, D. R., Grant, J. C. B., Sicnuer, H., DusBruL, E. palatoglossus muscle fibers are not actually L., and ParTaAN, J., Status of research in cleft palate: Anatomy and physiology, Part 1, Cleft Palate J., 11, extracted, they are likely to regain function 471-492, 1974. since even a minced muscle replaced into the Fara, M., and Dvorax, J., Abnormal anatomy of the bed from which it came will regenerate, rein- muscles of palatopharyngeal closure in cleft palates, nervate, and regain at least some degree of Plast. Reconstr. Surg., 46, 488-497, 1970. function (Carlson, 1972). Finally, elastin may FrowErrs, C. R., and Morris, H. L., Oral-pharyngeal movements during swallowing and speech, Cleft Palate also regenerate during the healing process J., 10, 181-191, 1973. (Bhangoo and Church, 1976) which would FritzELL, B., The velopharyngeal muscles in speech: An more fully restore the functional integrity of electromyographic and cineradiographic study, Acta the pillar-muscle mechanism. Otolaryng. Supp., 250, 1969. Acknowledgment: The initial stages of this Harkness, R. D., Mechanical properties of collagenous tissues, In Treatise on Collagen (B. S. Gould, ed.). N.Y.: project were conducted while Dr. Azzam was Academic Press, Vol. 2A, 248-310, 1968. Associate Professor in the Department of HorveE, H. J. H., A Manual of Dissection and Practical Anatomy, University of Iowa. All the anatom- Anatomy of Head and Neck. Des Moines, Iowa: Geo. A. ical material was kindly provided by this Miller, 515, 1910. HuntER, J. A. A., and Finutay, J. B., Scanning electron department. The authors wish to acknowl- microscopy of normal human scar tissue and keloids, edge the following individuals; Mr. Paul Rei- Br. J. Surg., 63, 826-830, 1976. mann for photographic assistance; Dr. KriEns, O., Anatomy of the velopharyngeal area in cleft Charles Beatty for assistance in dissection; palate, Clinics in Plast. Surg., 2, 261-283, 1975. Mr. John Snodgrass, the Chief Technician in LusxkrER, J. F., FritzeEr1, B., and Linpguist, J., Velopha- ryngeal function: An electromyographic study, Quart. the Gross Anatomy Laboratory, University of Prog. and Stat. Rept., Speech Trans. Lab., Royal Inst. lowa; and Mrs. Rita Azzam for histological Technol., Stockholm, No. 4, 9-20, 1970. sectioning and staining conducted in the De- LuskrER, J. F., and May, K., Palatoglossus function in partment of Human Morphology and Exper- normal speech production. Papers from the Institute of Linguistes, No. 17, Univ. of Stockholm, 1973. imental Pathology, Faculty of Medicine, Ku- LuscHKaA, H. von Der Schlundkofp des Menschen. H. Laupp's wait University, Kuwait. Buchhandlung, Tubingen, 1868. VrEaAu, F., Division Palatine. Paris; Masson and Cie, 1931. References WoopBURN, R. T., Essentials of Human Anatomy. (5th Ed.). ArEm, A. J., and MappEn, J. W., Effects of stress on N.Y.: Oxford University Press, 232, 1973. healing wounds: 1. Intermittent noncyclical tension, /. Yu, S. Y., and BuumentHar, H. T., The calcification of of Surg. Res., 20, 93-102, 1976. elastic tissue, In The Connective Tissue (B. M. Wagner, Brru-BERT1, F., An electromyographic study of velopha- ed.). Baltimore: Williams and Wilkins Co., 17-27, ryngeal function in speech, J. Speech Hear. Res., 19, 1967.