Surgical anatomy of the levator veli palatini: a previously undescribed tendinous insertion of the anterolateral fibers

The purpose of this study was to describe the previously unreported tendinous insertion of the anterolateral fibers of the levator veli palatini (levator) and discuss possible implications for levator function and cleft palate repair. The velopharyngeal anatomy in normal adult cadavers was studied, with histologic confirmation of anatomical findings. These findings were compared with a more limited study of levator anatomy in cleft palates at the time of intraoperative muscle dissection. Just before entering the velum, the levator divides into two parts. The smaller bundle of muscle fibers (anterolateral part) runs anteriorly, close to the lateral pharyngeal wall, and inserts into the palatine aponeurosis through a number of fine tendons. The main part of the muscle runs medially into the velum, where it fans out and forms the levator sling with the contralateral levator. The possible function of the anterolateral part of the levator is discussed. Inadequate release of the tendinous insertions at the time of palate repair may tether the levator anteriorly and compromise muscle retropositioning or may result in splitting of the levator, so that only part of the levator is retropositioned.     

Anatomy of the auditory tube and related structures in the rhesus monkey (Macaca mulatta).

The primate nasopharynx-auditory tube-middle ear complex is being used by several researchers to model both normal and pathologic functions of the human auditory tube. An extensive search of the literature has indicated little detailed information on the primate tube/middle ear system. This study was undertaken to define the anatomical characteristic of the system in the rhesus monkey (Macaca mulatta) and to determine the limits on the use of the monkey as a model of human tubal function. Although the direct application of morphologic data to account for the observed function of a system is a tenous one, the data on the rhesus monkey auditory tube appear to be consistent with those published for other mammals. The tensor veli palatini muscle appears to be the only muscle to act directly on the tube and effect tubal dilation. The muscle is attached to the lateral membranous tubal wall along its extrabullar extension. The muscle has an inferior attachment to the posterior hard palate and thus possesses a vector directed inferolaterally; contraction would appear to pull the membranous wall inferiorly and laterally, resulting in tubal dilation. The auditory tube relationships of the salpingopharyngeus, levator veli palatini, and internal pterygoid muscles are described. Their possible role in primate tubal function is minimal at best.     

Levator veli palatini muscle and eustachian tube function

Thirty previously unoperated patients with submucous cleft palate, occult submucous cleft palate, and unilateral congenital paralysis of the levator veli palatini muscle were examined. All patients were subjected to a comprehensive otoscopic, endoscopic, audiologic, and tympanometric evaluation. A correlation was made between levator veli palatini muscle anomalies, eustachian tube orifice anomalies, and middle ear ventilation and disorders. Normal middle ear ventilation was found in 23 patients. Negative middle ear pressure that consequently normalized following treatment of coexisting sinusitis was found in 3 patients. Only in 4 patients was chronic middle ear disease found. In one of them, middle ear effusion disappeared following successful treatment of sinusitis. Our conclusion is that the levator veli palatini muscle has no significant function in the opening mechanism of the eustachian tube and must be considered as a velopharyngeal valve muscle only.     

Morphology of the soft palate of the vervet monkey (Cercopithecus pygerythrus)

The heads of 31 vervet monkeys were dissected to investigate the morphology of the soft palate. This extended posteriorly from the hard palate and was delineated laterally by a fold raised by the pterygomandibular raphé. The palatoglossal arch was more prominent than the palatopharyngeal arch and four types of uvulae were seen. These were conical, bifid, trifid, and triangular. Twenty five to forty raised papillae were present on the anterior half of the oral surface. Within the soft palate, the bulk of tissue consisted of glands with a lesser amount of striated muscle. The muscles consisted of the tensor veli palatini, levator veli palatini, palatoglossus, palatopharyngeus, and uvular muscles which differed slightly in their attachments to similar muscles in man. The innervation of the tensor veli palatini muscle was a branch of the mandibular nerve but no nerves could be traced to the other muscles. The soft palate of the vervet monkey is sufficiently similar to that in man to be of practical use in experimental surgery aimed at correcting human soft palate abnormalities.     

The Levator Veli Palatini Muscle in Artiodactyls—A Comparative Ontogenetic Study

It is accepted in the literature that the levator veli palatini muscle of artiodactyls originates at the ectotympanic bone, a statement based on macroscopic dissection of adult specimens. The study of 34 histological serial sections of fetal heads of 23 species of artiodactyls revealed that this generalization must be modified: in the studied Camelidae, Suidae, Hippopotamidae, Giraffidae, and in some Bovidae (namely Tragelaphus and Antidorcas) the primary attachment of this functionally important muscle is at the tendinous intersection with the tensor veli palatini. Primary ontogenetic attachments are considered as relevant for defining homologies. By outgroup comparison (Felis and Diceros), this structural connection (character state 1) is also found in the Scrotifera—and hence may be considered as plesiomorphic for the Artiodactyla and its subunits. Only in the Tragulidae, Cervidae, Moschidae, and some Bovidae is a secondary attachment at the ectotympanic observed, which is interpreted as apomorphic for these taxa; possibly this character state 2 developed homoplastically several times. Bovidae show a mixed distribution of this character: Tragelaphus, Aepyceros, and Antidorcas show only a connection of the levator with the tensor veli; in Neotragus, Raphicerus, and Sylvicapra there exists an additional insertion at the ectotympanic; only Bos, Cephalophus, Damaliscus, and Ovis have a primary origin at the ectotympanic. It can be demonstrated in late fetal Sus that a secondary insertion of the levator veli at the ectotympanic is established during ontogeny; in a late fetal Ovis a secondary contact with the tensor veli is realized. The interpretation of this character distribution depends not only on an intrinsic polarity (‘Lesrichtung’), but also on the assumed character state of the groundplan of the common ancestor of the Bovidae. The anatomical observations are documented by photographs of relevant histological sections. The character states are mapped on a simplified and synoptic cladogram of extant artiodactyls; their pattern of evolutionary transformation as well as their relevance for the phylogenetic systematics of this mammalian order are discussed.     

弥猴单侧软腭肌肉对针式电极刺激的反应

目的建立针电极口内刺激猴软腭肌肉诱发腭咽闭合运动的模式,取得软腭肌肉运动的有效刺激数值,为软腭肌肉功能重建奠定基础。方法通过解剖成年猕猴软腭的五组肌肉,确定其体表位置;利用实验动物用腭部肌肉电极定位刺激器及针式电极对软腭肌肉进行有效刺激;结合鼻咽纤维镜、头颅侧位X片及软腭造影技术观察、记录肌肉收缩及腭咽闭合动作。结果在猕猴口内定位目标肌肉进行针电极刺激可诱发肌肉收缩。刺激电压为3 V、刺激频率为20 Hz时均能诱发单侧软腭肌肉的有效收缩;单侧腭帆提肌在刺激电压为5 V、20 Hz时可发生腭咽闭合动作。咽腭肌、舌腭肌在刺激电压5 V、刺激频率100 Hz时发生软腭下降动作。腭帆张肌仅发生收缩,而未发生腭咽闭合。应用鼻咽纤维镜和X线成像技术配合能记录腭咽闭合动作。结论弥猴可作为研究软腭肌肉运动模式的实验动物。应用电极刺激软腭肌肉,可初步建立腭咽闭合的动作模式。     

New therapsid specimens and the origin of the secondary hard and soft palate of mammals

A newly prepared palate of the moschorhinid therocephalian Promoschorhynchus platyrhinus from the Upper Permian region of South Africa was used for reconsidering the initial evolutionary development of the secondary palate of mammals. The very distinctive choanal crests are considered to be indicative of strong choanal folds that were probably already fused anteriorly. This gingival bridge probably served as the basis for the outgrowing bony processes of the hard palate that, in therapsids, developed independently at least three times. The soft palate ( velum palatinum ) is considered to be a remnant of the choanal folds that were muscularized from behind. It has been assumed that, in therapsids, a ventral portion of the medial pterygoid musculature shifted its insertion onto the ventral side of the pterygoid; this portion is supposed to have differentiated into the mm. tensor tympani and tensor veli palatini . Investigation of serial sections of extant marsupials confirm the view that the levator of the velum is derived from the upper constrictor of the pharynx. The choanal folds and the secondary palate are discussed within the wider framework of the evolutionary biology of mammalian forerunners. It is suggested that the formation of a sealed mouth cavity is not only related to the improved passage of air, but also to sucking in neonate hatchlings. The importance of the secondary palate of mammals to a number of resulting basic adaptations (dentition, olfactory system, etc.) of mammals is discussed.     

Engrailed Expression during Development of a Lamprey, Lampetra japonica: A Possible Clue to Homologies between Agnathan and Gnathostome Muscles of the Mandibular Arch

Developing lampreys were fixed at frequent intervals between the gastrula stage (6 days) and the earliest ammocoete larva (31 days). Expression of lamprey engrailed (en) gene was studied by labeling with a polyclonal antiserum (α Enhb-1 ) raised against mouse en protein. Western blotting of proteins from developing lampreys reveals a major band (40±10³ M_r ), which is probably lamprey en protein. Expression domains of en were demonstrated in developing lampreys by immunohistochemistry of whole mounts and histological sections. Expression of en first becomes detectable at the head protrusion stage (11/12 days) in neural tube cells at the mid/hindbrain boundary and soon thereafter in some mesodermal cells of the mandibular arch. These en -expressing cells of the mandibular arch are located in the walls of vesicles of paraxial mesoderm that originate by enterocoely on either side of the pharynx. At the tailbud stage (15 days), en expression is also detectable in mesodermal cells of the anterior lip and in some mesodermal and epidermal cells in the region of the tailbud. By the eye spot stage (18 days), detectable en expression in the mandibular arch becomes limited to cells of the velothyroideus muscles, which drive the power stroke of the recently formed velum. At later stages, while the preceding expression domains fade, en expression begins in some epidermal cells associated with the lip papillae, gill slits, and nostril. We suggest that the velothyroideus muscles of lampreys may be homologous to certain jaw muscles of teleosts–namely, the levator arcus palatini and the dilator operculi, which express en continuously while differentiating from the myogenic mesoderm into identifiable muscle types.     

Comparative anatomy of the cheek muscles within the Centromochlinae subfamily (Ostariophysi, Siluriformes, Auchenipteridae)

Glanidium melanopterum Miranda Ribeiro, a typical representative of the subfamily Centromochlinae (Siluriformes: Auchenipteridae), is herein described myologically and compared to other representative species within the group, Glanidium ribeiroi, G. leopardum, Tatia neivai, T. intermedia, T. creutzbergi, Centromochlus heckelii, and C. existimatus. The structure of seven pairs of striated cephalic muscles was compared anatomically: adductor mandibulae, levator arcus palatini, dilatator operculi, adductor arcus palatini, extensor tentaculi, retractor tentaculi, and levator operculi. We observed broad adductor mandibulae muscles in both Glanidium and Tatia, catfishes with depressed heads and smaller eyes. Similarities between muscles were observed: the presence of a large aponeurotic insertion for the levator arcus palatini muscle; an adductor arcus palatini muscle whose origin spread over the orbitosphenoid, pterosphenoid, and parasphenoid; and the extensor tentaculi muscle broadly attached to the autopalatine. There is no retractor tentaculi muscle in either the Glanidium or Tatia species. On the other hand, in Centromochlus, with forms having large eyes and the tallest head, the adductor mandibulae muscles are slim; there is a thin aponeurotic or muscular insertion for the levator arcus palatini muscle; the adductor arcus palatini muscle originates from a single osseous process, forming a keel on the parasphenoid; the extensor tentaculi muscle is loosely attached to the autopalatine, permitting exclusive rotating and sliding movements between this bone and the maxillary. The retractor tentaculi muscle is connected to the maxilla through a single tendon, so that both extensor and retractor tentaculi muscles contribute to a wide array of movements of the maxillary barbels. A discussion on the differences in autopalatine-maxillary movements among the analyzed groups is given.     

Soft palate muscle responses to negative upper airway pressure

The afferentpathways and upper airway receptor locations involved in negative upperairway pressure (NUAP) augmentation of soft palate muscle activity havenot been defined. We studied the electromyographic (EMG) response toNUAP for the palatinus, tensor veli palatini, and levator veli palatinimuscles in 11 adult, supine, tracheostomized, anesthetized dogs. NUAPwas applied to the nasal or laryngeal end of the isolated upper airwayin six dogs and to four to six serial upper airway sites from the nasalcavity to the subglottis in five dogs. When NUAP was applied at thelarynx, peak inspiratory EMG activity for the palatinus and tensorincreased significantly (P < 0.05) and plateaued at a NUAP of 10cmH₂O. Laryngeal NUAP failed toincrease levator activity consistently. Nasal NUAP did not increase EMGactivity for any muscle. Consistent NUAP reflex recruitment of softpalate muscle activity only occurred when the larynx was exposed to the stimulus and, furthermore, was abolished by bilateral section of theinternal branches of the superior laryngeal nerves. We conclude thatsoft palate muscle activity may be selectively modulated by afferentactivity originating in the laryngeal and hypopharyngeal airway.     

Velopharyngeal motion after sphincter pharyngoplasty: a videonasopharyngoscopic and electromyographic study

Sphincter pharyngoplasty is a surgical procedure for managing velopharyngeal insufficiency after palatal closure. This procedure is intended to create an active diaphragm for velopharyngeal closure. The purpose of this study was to evaluate velopharyngeal motion after sphincter pharyngoplasty, by using selective electromyography and simultaneous videonasopharyngoscopy. Twenty-five patients who were subjected to sphincter pharyngoplasty from 1985 to 1996 were reviewed. All conditions were evaluated by using electromyography with simultaneous videonasopharyngoscopy. The following velopharyngeal muscles were examined: superior constrictor pharyngeus, palatopharyngeus, and levator veli palatini. The palatopharyngeus was included in the superiorly based surgical flaps inserted at the posterior pharyngeal wall. Twenty-three patients (92 percent) showed complete velopharyngeal closure. The two patients with residual velopharyngeal insufficiency showed a defect size of 20 and 25 percent. None of the patients showed electromyographic activity at the superiorly based flaps, indicating absence of activity of the palatopharyngeus muscles. However, all patients showed normal electromyographic activity at the superior constrictor pharyngeus and the levator veli palatini. Videonasopharyngoscopy demonstrated that lateral pharyngeal wall movements, which ranged from 25 to 40 percent, were related to strong electromyographic activity at the superior constrictor pharyngeus. It is concluded that the superiorly based pharyngeal flaps of the sphincter pharyngoplasty do not seem to create an active diaphragm for velopharyngeal closure. Moreover, the observed sphinctering seems to be passive, caused by the contraction of the superior constrictor pharyngeus.     

Eustachian tube cartilage and medial movement of lateral pharyngeal wall on phonation

Several authors have demonstrated the importance of medial movement of the lateral pharyngeal wall in velopharyngeal closure upon phonation. However, it remains controversial what muscle is responsible for lateral pharyngeal wall movement and where is the main site of this movement. The purpose of this study was to address the above two unanswered questions. In 22 subjects (12 normal volunteers, 10 patients with cleft palate), lateral pharyngeal wall movement upon phonation was evaluated by using rapid magnetic resonance imaging (MRI). Before rapid MRI, their lateral pharyngeal wall movements were classified into three groups: the poor, moderate, and good, according to the findings of nasopharyngoscopy. Inward displacement of the eustachian tube cartilages upon phonation, which was quantified as distance ratio in the transverse plane of MR images, was compared with nasopharyngoscopic findings. In addition, the level of lateral pharyngeal wall movement was observed in the plane 5 mm lateral to the mid-sagittal plane of MR images. Inward displacement of the eustachian tube cartilage in the transverse plane of MR images was coincident with medial movement of lateral pharyngeal wall observed by nasopharyngoscopy in all 22 subjects. By using one-way analysis of variance, a statistically significant correlation was found between nasopharyngoscopic classification and distance ratio. The sagittal plane of MR images revealed that the main site of movement occurred at the level of the hard palate and above. It is concluded that medial movement of the lateral pharyngeal wall consists of inward displacement of the eustachian tube cartilage, which is caused by contraction of the levator veli palatini muscle, and that the primary site of this movement is at the level of the hard palate and above, where the eustachian tube, but not the superior constrictor muscle, exists.     

Ontogeny of the suspensorial and opercular musculature in the suckermouth armoured catfish <Emphasis Type="Italic">Ancistrus</Emphasis> cf. <Emphasis Type="Italic">triradiatus</Emphasis> (Loricariidae,Siluriformes)

Several morphological features characterizing Loricariidae or suckermouth-armoured catfishes (Siluriformes, Teleostei) are related to their ability to attach onto substrates with their sucker mouth, and to scrape algae and other food items from these substrates. Suspensorial and opercular muscles are among those muscles usually involved in respiration (and feeding). In several loricariids including the genus Ancistrus, the opercular musculature is decoupled from the respiratory mechanisms. Results show that the adductor arcus palatini is relatively large throughout the whole ontogeny, while the levator arcus palatini is minute. It develops in association with the dilatator operculi, which exhibits substantial growth only in the juvenile and adult stages. The levator and adductor operculi are connected during early ontogeny, and anterior fibres of the latter muscle differentiate into the adductor hyomandibulae, a muscle previously thought to be absent in loricariids. Relative muscle sizes and orientations, as well as articular transformations and the transition from cartilaginous to bony skeletal elements, indicate ontogenetic transformations in the skeleto-muscular system, affecting and steering functionalities.     

Results with Furlow palatoplasty in management of velopharyngeal insufficiency.

A retrospective study was undertaken to assess speech outcomes in patients undergoing Furlow palatoplasty. Since 1994, the authors have used the position of the levator veli palatini musculature to determine type of surgical intervention recommended for the management of velopharyngeal insufficiency. Furlow palatoplasty has been used in patients with clinical evidence of sagittally oriented levator veli palatini musculature. Forty-eight patients who underwent a Furlow palatoplasty between June of 1994 and August of 1998 were included. All patients underwent preoperative and postoperative perceptual speech analyses to describe velopharyngeal insufficiency severity, nasal air emissions, and resonance, and preoperative nasendoscopy to assess velopharyngeal gap size and palatal and lateral pharyngeal wall movement. Other patient characteristics considered included gender, age at time of surgery, previously repaired cleft palate, submucous cleft palate, and syndrome diagnosis. Speech outcomes were determined on the basis of postoperative perceptual speech analyses and were categorized in one of three ways: (1) complete resolution of velopharyngeal insufficiency, (2) substantial improvement of velopharyngeal insufficiency, and (3) audible residual velopharyngeal insufficiency. Complete resolution of velopharyngeal insufficiency was defined as normal resonance and an absence of nasal air emissions. Substantial improvement of velopharyngeal insufficiency was defined as an improvement of at least two categories in velopharyngeal insufficiency severity in those patients without complete resolution. Audible residual velopharyngeal insufficiency refers to patients with postoperative velopharyngeal insufficiency severity ratings of mild, moderate, or severe. The male:female ratio in the study was 27:21. Twelve patients were syndromic; three had velocardiofacial syndrome. The median age at surgery was 6.5 years (range, 2 to 22 years). The average duration of follow-up was 14.7 months (range, 1.3 to 58.6 months). Postoperatively, the severity of velopharyngeal insufficiency was rated as none in 19 of the 48 patients (39.6 percent), minimal in eight (16.7 percent), mild in six (12.5 percent), moderate in nine (18.75 percent), and severe in six (12.5 percent). Substantial improvement was seen in seven of the 29 patients without complete resolution. There was a significant association between male gender and complete resolution of velopharyngeal insufficiency (p < 0.05). Presence of syndrome and female gender was associated with audible residual velopharyngeal insufficiency (p < 0.05). The main complication was palatal fistula (two cases). In conclusion, most patients who underwent a Furlow palatoplasty had a complete resolution or substantial improvement of velopharyngeal insufficiency postoperatively, and there were few surgical complications.     

Ontogeny of the jaw and maxillary barbel musculature in the armoured catfish families Loricariidae and Callichthyidae (Loricarioidea,Siluriformes), with a discussion on muscle homologies

The neotropical loricarioid catfishes include six families, the most species‐rich of which are the Callichthyidae and the Loricariidae. Loricariidae (suckermouth armoured catfishes) have a highly specialized head morphology, including an exceptionally large number of muscles derived from the adductor mandibulae complex and the adductor arcus palatini. Terminology of these muscles varies among the literature, and no data exist on their ontogenetic origin. A detailed examination of the ontogeny of both a callichthyid and a loricariid representative now reveals the identity of the jaw and maxillary barbel musculature, and supports new hypotheses concerning homologies. The adductor mandibulae muscle itself is homologous to the A1‐OST and A3′ of basal catfishes, and the A3′ has given rise to the newly evolved loricariid retractor veli as well. The A2 and A3″ have resulted in the retractor tentaculi of Callichthyidae and the retractor premaxillae of Loricariidae. Thus, these two muscles are shown to be homologous. In Loricariidae, the extensor tentaculi consists of two separate muscles inserting on the autopalatine, and evidence is given on the evolutionary origin of the loricariid levator tentaculi (previously and erroneously known as retractor tentaculi) from the extensor tentaculi, and not the adductor mandibulae complex. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 76–96.     

Branchial arch muscle innervation by the glossopharyngeal (IX) and vagal (X) nerves in tetraodontiformes, with special reference to muscle homologies

Branchial arch muscle innervation by the glossopharyngeal (IX) and vagal (X) nerves in 10 tetraodontiform families and five outgroup taxa was examined, with special reference to muscle homologies. Basic innervation patterns and their variations were described for all muscle elements (except gill filament muscles). In the tetraodontids Takifugu poecilonotus and Canthigaster rivulata, diodontid Diodon holocanthus, and molid Mola mola, levator externus 4 was innervated by the 3rd vagal branchial trunk (BX3) in addition to BX2, owing to strong posterior expansion of the muscle. Based on nerve innervation, migrations of the muscle attachment sites (i.e., origins and insertions) were recognized in levator internus 2 (in Mola mola), obliquus dorsalis 3 (in Ostracion immaculatus and Canthigaster rivulata), and obliquus ventralis 2 (in Stephanolepis cirrhifer), muscle topologies not necessarily being indicative of homologies. Embryonic origin of the retractor dorsalis and parallel attainment of the swimbladder muscle within the order were also discussed.     

Levator advancement technique for eyelid ptosis

There have been many procedures advocated for the treatment of eyelid ptosis. The technique advocated in this paper consists of careful dissection and identification of anatomic landmarks, including preaponeurotic fat, Whitnall's superior transverse ligament, and the vertically oriented blood supply of the levator muscle. The attachment of the levator muscle into the cephalad portion of the levator muscle into the cephalad portion of the levator aponeurosis can be identified and easily dissected in order to perform the procedure of detachment and advancement to the tarsal plate. This procedure for ptosis has been successful in management in moderate to severe ptosis and in some cases has actually increased the muscle function, thereby enhancing the result. In this technique, the full length of levator muscle remains, so maximum excursion is achieved postoperatively. In addition, this surgical approach may be utilized for levator-lengthening procedures in cases of thyroid exophthalmus or overcorrected ptosis simply by performing the reverse procedure of detachment and insertion of a spacer based on the same ratio. Good results have been achieved in over 20 patients, with the exception of two patients who had absent to poor function and in whom undercorrection was present postoperatively.