The "levator septi nasi muscle" and its clinical significance

It is strange that all textbooks of anatomy describe the depressor septi nasi muscle singly, without an antagonist. Incidentally, in 1986, a small rod of soft tissue was found between the medial crura of the two alar cartilages during a rhinoplastic operation with the external approach technique of Anderson and Ries. From 1990 through 1995, anatomic dissections of the nasolabial region under 3.5x loupe magnification were performed on 14 Chinese formalin-preserved cadavers, one fresh Chinese cadaver, and one fresh American white female cadaver. The small soft-tissue rod was found in every one of the dissected cadavers, and it was seen to be a pair of muscles. Each one of these paired small muscles arose from the aponeurosis on the dorsum of the nose and inserted into the muscular substance of the upper lip at the base of the columella and to the anterior spine of the maxilla. Histologic examinations of these muscles stained with hematoxylin and eosin and Masson trichrome showed that they were striated muscles. According to its origin and insertion, this newly found muscle was called the "levator septi nasi." Its clinical significance in cleft lip deformity and its relations to the orbicularis oris muscle, the dermocartilaginous ligament of Pitanguy, and the nasal superficial musculoaponeurotic system of Letourneau and Daniel are all discussed.     

Dynamic rhinoplasty for the plunging nasal tip: functional unity of the inferior third of the nose

To achieve permanent results for the correction of a drooping nasal tip, it is important to understand the mechanism responsible for the caudal rotation of the tip when a person speaks or smiles. This mechanism can be considered to depend on a "functional unity" formed by three components: (1) the cartilaginous framework (alar cartilages and accessories acting as a single structure); (2) muscular motors (m. levator labii superioris alaeque nasi and depressor septi nasi); and (3) gliding areas (apertura piriformis, the valvular mechanism between the upper lateral cartilages and alar cartilages, the lax tissue of the nasal dorsum, and the membranous septum). We describe a new anatomical and functional concept responsible for the plunging of the nasal tip. When a person smiles, the functional unit is activated by a combination of two forces acting simultaneously in opposite directions that rotate the tip caudally and elevate the nasal base. The levator moves the alar base upward and the depressor pulls the tip caudally. To correct the drooping tip, the transcartilaginous incision is extended laterally, and the lateral portion of the alar arch is dissected free from the skin and the mucosa, thus exposing the accessory cartilages. The arch is then severed at the level of the accessories to allow the cephalad rotation of the domes. The muscle insertions are dissected free from the accessories and a section of the muscle and, if necessary, the accessory cartilages, is removed. From January of 1991 onward, 312 patients have had this ancillary procedure performed in addition to the basic rhinoplasty technique.     

Mechanisms of control of alae nasi muscle activity.

Human upper airway dilator muscles are clearly influenced by chemical stimuli such as hypoxia and hypercapnia. Whether in humans there are upper airway receptors capable of modifying the activity of such muscles is unclear. We studied alae nasi electromyography (EMG) in normal men in an attempt to determine 1) whether increasing negative intraluminal pressure influences the activity of the alae nasi muscle, 2) whether nasal airway feedback mechanisms modify the activity of this muscle, and 3) if so, whether these receptor mechanisms are responding to mucosal temperature/pressure changes or to airway deformation. Alae nasi EMG was recorded in 10 normal men under the following conditions: 1) nasal breathing (all potential nasal receptors exposed), 2) oral breathing (nasal receptors not exposed), 3) nasal breathing with splints (airway deformation prevented), and 4) nasal breathing after nasal anesthesia (mucosal receptors anesthetized). In addition, in a separate group, the combined effects of anesthesia and nasal splints were assessed. Under each condition, EMG activity was monitored during basal breathing, progressive hypercapnia, and inspiratory resistive loading. Under all four conditions, both load and hypercapnia produced a significant increase in alae nasi EMG, with hypercapnia producing a similar increment in EMG regardless of nasal receptor exposure. On the other hand, loading produced greater increments in EMG during nasal than during oral breathing, with combined anesthesia plus splinting producing a load response similar to that observed during oral respiration. These observations suggest that nasal airway receptors have little effect on the alae nasi response to hypercapnia but appear to mediate the alae nasi response to loading or negative airway pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Morphology and variability of masticatory structures in the orangutan

The present study examines and describes variability and ontogenetic change in the masticatory structures of the orangutan. Mm. temporalis, masseter, pterygoideus lateralis, and pterygoideus medialis as well as m. digastricus are dissected, described, and removed unilaterally for drying from a sample of 10 orangutans. The temporomandibular joint and related structures are also described. Results indicate substantial interindividual variability in muscle morphology as well as possible age-related changes. Age-related changes in m. temporalis include an expansion of attachment area, adjustments in fiber direction, and changes in related bony structures. An increased attachment area is likewise seen in m. masseter in older individuals. Age-related variation is also seen in the position and extent of the origin of m. digastricus as well as in its fiber direction. A comparison of muscle weights indicates that m. pterygoideus lateralis is relatively larger in the neonate, whereas in the older individuals, it is relatively smaller compared to other masticatory muscles. The general morphology of the masticatory structures in the orangutan resembles that of other extant great apes and humans with the exception of m. digastricus. The orangutan differs in possessing only a posterior belly of this muscle.     

Breathing route influences upper airway muscle activity in awake normal adults

Both nasal obstruction and nasal anesthesia result in disordered breathing during sleep in humans, and bypassing the nasal route during tidal breathing in experimental animals produces decreased electromyographic activity of upper airway (UA) dilating muscles. To investigate UA responses to breathing route in normal awake humans, we studied eight healthy males (ages 21-38 yr) during successive trials of voluntary nose breathing (N), voluntary mouth breathing (M), and mouth breathing with nose occluded (MO). We measured genioglossus electromyographic activity (EMGgg) with perorally inserted bipolar electrodes, alae nasi (EMGan) and diaphragm EMG activity (EMGdi) with surface electrodes, and minute ventilation (VE) with a pneumotachograph. Mean phasic inspiratory EMG activity of both UA muscles was significantly greater during N than during M or MO, even when a 2.5-cmH2O.l-1.s inspiratory resistance was added to MO (P less than 0.01). In contrast, neither EMGdi nor VE was consistently affected by breathing route. EMGgg during N was significantly decreased after selective topical nasal anesthesia (P less than 0.002); a decrease in EMGan did not achieve statistical significance. These data suggest that peak UA dilating muscle activity may be modulated by superficial receptors in the nasal mucosa sensitive to airflow.     

禄丰古猿雌性头像的复原

本文叙述了制作禄丰古猿雌性复原头像的根据和过程。复原像以宽阔的眶间宽和中面部,以及低平的鼻根和鼻梁硬骨部为其显著的特点。它的“鼻—前颌部”侧面轮廓和软鼻形态与猩猩的较相似。它的鼻属猿型鼻,有类似大猩猩的和人形化的性状。     

Denervation syndrome in the rat digastric muscle

Excitability parameters of m. digastricus muscle fibers were investigated in anesthetized (40 mg/kg of nembutal) rats 3-5 days after denervation. The number of fibers with high polarization level was increased as was the number of fibers with low and medium level in both bellies of m. digastricus. The differences in the level of polarization recorded in the muscle fibers of the abdominoposterior m. digastricus disappeared after denervation. It is suggested that denervation syndrome in m. digastricus deprived of spindle receptors was similar to that observed in other skeletal muscles.     

Alae nasi electromyographic activity and timing in obstructive sleep apnea

The alae nasi is an accessible dilator muscle of the upper airway located in the nose. We measured electromyograms (EMG) of the alae nasi to determine the relationship between their activity and timing to contraction of the rib cage muscles and diaphragm during obstructive apnea in nine patients. Alae nasi EMG were measured with surface electrodes and processed to obtain a moving time average. Contraction of the rib cage and diaphragm during apneas was detected with esophageal pressure. During non-rapid-eye-movement (NREM) sleep, there was a significant correlation in each patient between alae nasi EMG activity and the change in esophageal pressure. During rapid-eye-movement (REM) sleep, correlations were significantly lower than during NREM sleep. As the duration of each apnea increased, the activation of alae nasi EMG occurred progressively earlier than the change in esophageal pressure. We conclude that during obstructive apneas in NREM sleep, activity of the alae nasi increases when diaphragm and rib cage muscle force increases and the activation occurs earlier as each apneic episode progresses.     

Analysis of the African American female nose

The African American nose has been broadly classified as ethnic yet it differs significantly in morphology from that of other ethnic groups with which it is categorized. The objectives of this study were to (1) establish an objective protocol for analysis of the African American female nose using anthropometric measurements, and (2) determine whether subjective subcategorization schemes are a reliable replacement for anthropometry. African American women (n = 107) between the ages of 18 and 30 years consented to participate in this study. Photographs and 14 standard anthropometric measurements were taken of the face and nasal region, including nose length, nose width, special upper face height, intercanthal distance, mouth width, nasal bridge inclination, nasal tip protrusion, ala thickness, nasal root width, nasal bridge length, tangential length of ala, length of columella, nasofrontal angle, and nasolabial angle. Nasal indices including nose width-nose height index, nasal tip protrusion-nose height index, and nasal tip protrusion-nasal width index were calculated. In addition, photographic analysis was performed to evaluate nostril shape, nasal base shape, and nasal dorsal height. Proportional relationships and subcategorization schemes were evaluated. A new method of nasal analysis for the African American woman uses the proportional relationships of the anthropometric measurements. Proportional relationships included a columellar to lobule ratio of 1.5:1, a nasolabial angle of 86 degrees, and an alar width to intercanthal distance ratio of 5:4. The nasal dorsal height classification scheme was the most reliable for subjective analysis. The degree of variability found within this group of young African American women is illustrated by the following indices and their respective ranges: nose width-nose height index mean, 79.7 (range, 57 to 102); nasal tip protrusion-nose height index mean, 33.8 (range, 23 to 46); and nasal tip protrusion-nose width index mean, 42.8 (range, 32 to 61). The guidelines provided are a baseline from which to begin analysis and evaluation.     

Nasal reconstruction using both cranial bone and ear cartilage

In this article, an anatomic reconstruction is described using cranial bone graft for the bony part of the nose while reconstructing the cartilaginous part with ear cartilage. This modification provides protection of the nose from the traumatic forces creating a flexible nasal tip. A modification is described and compared with the nasal reconstruction by calvarial bone itself.     

Morphologic and genetic studies of the nose

The aim of this paper is to find metrical and morphological shape variants of the nose, which are highly determined by heredity. For this, 67 monozygotic and 59 dizygotic twins were measured and the morphological details of the nasal region were recorded and documented by taking photographs in the three standard views of the nose. The study of shape variants in our population was based on 160 control persons, who were not related. Out of this group 61 control pairs were put together by random selection with regard to sex and age. From every examined person data of 9 metrical and 43 well distinguishable morphological variants of the nose were gathered. They had been worked out of numerous observable forms. It could be shown that two measures (breadth of the nose, breadth of the tip of the nose) and eight other morphological features of the nose are of good heredity.     

Ontogeny of the cranial musculature in Corydoras aeneus Callichthyidae,Siluriformes

A complete study of the early ontogeny of the cranial muscles of Corydoras aeneus (Callichthyidae) was undertaken and results were compared with those for the loricariid Ancistrus cf. triradiatus. This comparison reveals a high degree of similarity in the ontogeny of both species' cranial muscles. Both species lack a musculus protractor hyoidei, and the musculus intermandibularis posterior is divided into two different parts that have partly obtained a novel function (serving the lower lip) in A. cf. triradiatus. A similar increase in muscular complexity in this species is found in the dorsal constrictor of the hyoid muscle plate. This constrictor gives rise to the same muscles in both C. aeneus and A. cf. triradiatus, but in A. cf. triradiatus the musculus levator operculi later hypertrophies. In C. aeneus the musculus extensor tentaculi forms a single muscle diverging posteriorly, whereas in A. cf. triradiatus the musculus extensor tentaculi differentiates into two separate bundles. Also, a loricariid neoformation is present called the musculus levator tentaculi.     

THE MUSCULAR HYDROSTAT OF THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS): A FUNCTIONAL MORPHOLOGICAL MODEL OF PERIORAL BRISTLE USE

Facial musculature was examined in the Florida manatee, Tricbecbus manatus latirostris , in order to develop a functional model of perioral bristle use. Muscles identified include the M. levator nasolabialis, M. buccinatorius, M. maxillonasolabialis, M. centralis nasi, M. lateralis nasi, M. spbincter colli profundus pars oris, M. orbicularis oris, M. mandibularis, and M. mentalis. A new muscle, M. centralis nasi , has been named and is an integral part of perioral bristle movement. The snout of the Florida manatee is capable of performing complex movements. The prehensile ability of Florida manatees can be explained in the context of a muscular hydrostat as defined by Kier and Smith (1985). Eversion of certain bristles in the upper lip occurs by shortening longitudinal, transverse, and semicircular muscles in combination with volume displacement due to compensatory changes in the shape of the snout. Midline sweeping of these bristles is accomplished by the contraction of M. centralis nasi. Eversion of bristles on the lower jaw is a result of shortening of M. mentalis. Contraction of M. orbicularis oris pushes vegetation into the oral cavity. All observed movement patterns and uses of perioral bristles can be explained by variation of these sequences within the context of muscular hydrostat function.     

The morphological and histological characters of the male external genitalia of the house musk shrew, Suncus murinus

External genitalia are the reproductive organs necessary for efficient copulation and internal fertilization in various mammalian species. Their morphogeneses display significant morphological and developmental differences among species. The house musk shrew, Suncus murinus (hereafter described as suncus) is a species of the order Insectivora, which has been considered as primitive and one of the earliest eutheria phylogenetically. Comparative anatomical analyses of phylogenetically different mammals will contribute to the better understanding of morphological diversity of external genitalia. This study performed various anatomical and histological analyses concerning the organization of the external genitalia of male suncus. It was shown that the external genitalia of suncus possessed a muscular structure, which we proposed as musculus ischiocavernosus dorsalis of suncus. The musculus ischiocavernosus dorsalis is originated from the inner surface of the tuber ischiadicum and was allocated adjacent to the corpus cavernosum penis. In addition, a pair of alpha-smooth muscle actin positive muscles was located bilaterally to the urethra. This unique morphology of the external genitalia of suncus males may provide a unique model system to investigate genital morphogenesis.     

Topography and structure of the stylohyoid muscle in mammals

Topography and structure of the musculus stylohyoideus (MSH) have been studied in 78 species of Mammalia from 12 orders. The muscle in question has specific peculiarities not only in its position and fixation, but also in a great variability of its structure. The MSH is not revealed in Philander opossum, Lagostrophus fasciatus, guinea pig, Meriones eversmanni, Rhombomys opimus, Nyctereutes procyonoides, Thos aureus, Mastelidae. Various pathways of development and different functional loading define existence of several modifications of the MSH: a) the medial part of the muscle develops (Didelphys, Rodentia, Insectivora, Proboscidea, Dama dama, Capreolus capreolus; b) the lateral part of the musculus develops (Lagomorpha, Canis lupus, Ursidae, Felidae, Pinnipedia, Cavicornia); c) both parts of the musculus develop, determining position of the m. digastricus between these two parts (Alces alces, Pseudaxis sica, Cervus elaphus, Macaca rhesus, Erythrocebus patas, Perissodastyla).     

Dynamics of rhinoplasty

Nasal dynamics were studied on 87 patients undergoing rhinoplasty of one zone or two distant nasal zones. Statistical analysis of the result revealed that reduction of the nasion area, besides setting the soft tissue back, gave the appearance of increased intercanthal distance and lengthened the nose. Reduction of the nasal bridge resulted in a wider appearance on front view and a cephalically rotated tip on profile. Augmentation of the bridge affected the nose reversely. Tip cephalad rotation was achieved by resecting one of the three areas: the cephalad portion of the lower lateral cartilages (affecting the rims more), the caudal septum (affecting the central portion more), and the caudal portion of the medial crura of the lower lateral cartilages (affecting the central portion only). Resection of the alar base not only narrowed the nostrils but also moved the alar rim caudally. Furthermore, it reduced tip projection when a large alar base reduction was done. Reduction of the nasal spine increased the upper lip length on profile and reduced tip projection when a large reduction took place. Significant reduction in caudal nose projection resulted in widening of the alar base.     

Absolute strength of the muscles attached to the mandible

In the course of an anatomical investigation of the muscles, securing movements of the mandible, performed on 10 human corpses, the muscle fibre length, volume and weight of each muscle has been estimated. Owing to the formula suggested by P. F. Leshaft (1880)--q = v/e, the physiological diameter of the muscles has been determined. Since the muscle with the diameter equal to 1 cm2 develops an absolute forse of 10 kg, the absolute muscle force value of the anterior group of muscles has been obtained for the first time (venter anterior musculi digastri--4.8 kg, musculus mylohyoideus--10.7 kg and musculus geniohyoideus--6.3 kg). The data on the absolute force of the posterior group of muscles has been verified (musculus masseter--24.2 kg, musculus temporalis--28 kg, musculus pterygoideus medialis--15.6 kg and musculus pterygoideus lateralis--15.5 kg). Analysing the interaction of forces of the muscles participating in the mandible movements, direction and value of displacements of the mandibular fragments have been explained and confirmed on some clinical examples. The data on the absolute force of the muscles studied can be used for investigating the displacement mechanism of the mandibular fragments after its resection and when its integrity is broken.     

Non-specific esterases and esterproteases in masticatory muscles from the muscular dystrophic mouse

With the aid of histochemical and electrophoretic techniques activities for esterase and esterprotease were investigated in the digastric and masseter muscles from normal and dystrophic mice. The substrates used were -naphthyl acetate and N-acetyl-l-alanine -naphthyl ester. According to the microscopic observations of the dystrophic muscles the histopathological changes in the masseter muscle were much more pronounced than in the digastric muscle. The connective tissue surrounding the myofibers of the dystrophic masseter contained a large number of cells with pronounced enzyme activity. Among them were mast cells that were strongly stained for esterprotease. The connective tissue of the dystrophic digastricus was much less infiltrated with cellular elements reacting for esterprotease. In zymograms the normal digastricus, the dystrophic masseter and the dystrophic digastricus showed a strong activity for certain isoenzymes that were absent or weakly expressed in the normal masseter.This study was supported by grand No. 12-6516 from the Danish Medical Research Council     

Dynamics in rhinoplasty

Nasal dynamics were studied on 87 patients undergoing rhinoplasty of one zone or two distant nasal zones. Statistical analysis of the results revealed that reduction of the nasion area, besides setting the soft tissue back, gave the appearance of increased intercanthal distance and lengthened the nose. Reduction of the nasal bridge resulted in a wider appearance on frontal view and a cephalically rotated tip on profile. Augmentation of the bridge affected the nose reversely. Tip cephalad rotation was achieved by resecting one of the three areas: the cephalad portion of the lower lateral cartilages (affecting the rims more), the caudal septum (affecting the central portion more), and the caudal portion of the medial crura of the lower lateral cartilages (affecting the central portion only). Resection of the alar base not only narrowed the nostrils but also moved the alar rim caudally. Furthermore, it reduced tip projection when a large alar base reduction was done. Reduction of the nasal spine increased the upper lip length on profile and reduced tip projection when a large reduction took place. Significant reduction in caudal nose projection resulted in widening of the alar base.