Deep Neck Contouring With a Focus on Submandibular Gland Vascularity: A Cadaver Study.

BACKGROUND: Opening the neck through a submental incision allows accurate management of deep neck structures and results in exceptional neck contours. OBJECTIVES: The authors aimed to evaluate the distribution of deep neck structures and investigate the detailed vascular anatomy of the submandibular gland. METHODS: A total of 26 fresh frozen cadaver heads (15 female, 11 male) were utilized. The authors evaluated the weights of the excised tissues simulating cosmetic resections, including subcutaneous fat, subplatysmal fat, the anterior belly of the digastric muscle, and submandibular glands. The vascular supply of the submandibular gland and intracapsular vessel diameters were also investigated. RESULTS: Whereas female cadavers had greater mean tissue weight removed from the supraplatysmal plane (mean 20.9 g, 56.6%) than the subplatysmal plane (16 g, 43.4%), male cadavers had higher mean tissue weight removed from the subplatysmal plane (10.5 g, 60.7%) than the supraplatysmal plane (mean 6.8 g, 39.3%). The mean subcutaneous (6.8 g) and subplatysmal (6.4 g) fat weights were almost equal in male cadavers; mean subcutaneous fat weight (20.9 g) was 3 times higher than subplatysmal fat weight (6.8 g) in female cadavers. There was a statistically significant relationship between body mass index and fat removed. The intraglandular vessel diameters increased as resections approached the main feeding vessels located posterosuperior (facial artery) and anterosuperior (submental artery) to the submandibular gland. CONCLUSIONS: The results suggest that to achieve exceptional neck contour the structures deep to the platysma often need to be addressed. The submandibular gland reduction can be safely performed with comprehensive understanding of its vascular anatomy.

Clinical Anatomy of Feeding Artery of the Submandibular Gland.

ABSTRACT: The purpose of this study was to investigate the clinical anatomy of the feeding artery of the submandibular gland (SMG). A total of 199 SMG removals were performed in extraoral or intraoral approach with/without endoscopic assistance by a single surgeon. The feeding artery of the SMG was always identified intraoperatively and recorded in the operation record. The clinical anatomy of the feeding artery of the SMG was investigated based on the intraoperative findings. The facial artery was ligated and transected for the involvement of tumor or severe inflammation in 16 (8.0%) procedures. The feeding artery was investigated in the remaining 183 procedures. The mean number of the glandular branch was 1.5. There were 1 branch in 98 procedures (53.6%), 2 branches in 80 procedures (43.7%), and 3 branches in 5 procedures (2.7%). Detailed anatomical knowledge of the feeding artery of the SMG is useful for proper dissection of the SMG and preservation of the facial artery.

Evolution of the strikingly diverse submandibular muscles in Anura.

The most ventral muscles of the head (the mm. submentalis, intermandibularis, and interhyoideus) provide support to the gular region and lift the buccal floor during ventilation and feeding. These muscles show limited variation in most gnathostomes, but in Anura they exhibit a surprising diversity. The few studies that have explored this character system highlighted its potential as a source of phylogenetic information. In this paper we explored the diversity of this character system studying specimens of 567 anuran species and reviewing published data to cover a total of 1321 species, belonging to 53 of the 54 currently recognized anuran families, as well as caudates and caecilians. We defined 27 discrete characters including the number of muscle bellies, supplementary layers, hypertrophy and diversity of elastic fibres, and pigmentation, among others, and optimized them on a comprehensive phylogenetic hypothesis. We recognized 223 unambiguously optimized synapomorphies for numerous clades on different scales, including three for Anura and many for suprafamiliar clades with poor phenotypic support. Finally, we discussed the evolution of this highly diverse character system, including homology, development, and its functional role in vocalization and feeding. Interestingly, the striking levels of variation in some structures contrast with the amount of phylogenetic inertia, allowing us to recognize several general patterns. Supplementary elements of the m. intermandibularis evolved first as broad layers occuring in more than half of extant anuran species and then concentrated forming discreet bellies in several clades. The anterior portion of the gular region is not sexually dimorphic, and is likely related to ventilation and tongue protraction. Conversely, the diversity of the m. interhyoideus is strongly linked to vocal sacs, which are present only in adult males, suggesting the presence of two independent modules.

Características morfocuantitativas de la glándula submandibular de ratón (Mus musculus) / Morphocuantitative characteristics of the mouse (Mus musculus) submandibular gland

El ratón (Mus musculus) es un buen modelo animal de experimentación, donde sus glándulas salivales han sido utilizadas en estudios, especialmente de tipo preclínico. Sin embargo, las diferencias en la morfología de estas glándulas y, en particular de las submandibulares, entre humanos y roedores no son de conocimiento común. Por lo anterior, el objetivo de este estudio fue conocer las características morfocuantitativos de la glándula submandibular del ratón macho C57BL/6. Se utilizaron cinco ratones macho, cepa C57BL/ 6, de 11 a 13 semanas de nacidos, con un peso promedio de 30 g. Luego de su ambientación, los ratones fueron eutanasiados. Para el análisis histológico, las glándulas fueron extraídas y fijadas en formalina tamponada por 48 horas, procesada para su inclusión en paraplast y teñidas con hematoxilina y eosina, azul alcián pH 2,5, ácido peryódico de Schiff y Picrosirius Red. Se determinaron las características estereológicas de densidad de longitud (LVcond), de volumen (VVcond) y de superficie (SVcond) de los conductos. En las células acinares se evaluó la densidad de número (NVcel) y la densidad de volumen (VVcel). Para cada variable se obtuvo la media ± desviación estándar. La glándula submandibular se encontraba organizada de manera lobulada, cuyo parénquima era de tipo túbuloacinar mixto con predominio seroso, que se conectaba a través de conductos. Las células acinares presentaban reacción positiva para azul alcián y ácido peryódico de Schiff. El estroma de la glándula contenía principalmente colágeno tipo 1. Los resultados de las mediciones estereológicas fueron: LVcond = 220,02 ± 50,51 mm/mm3; VVcond = 50,48 ± 9,55 %; SVcond = 26,39 ± 5,45 mm2/mm3; NVcel = 16,85 x 104 ± 9,13 × 104/mm3; VVcel = 24,98 ± 6,22 %. Con los análisis presentados es posible realizar investigaciones experimentales, considerando las similitudes y diferencias morfocuantitativas que presenta la glándula submandibular de ratón macho, cepa C57BL/6 con la del humano.

The mouse (Mus musculus) is a good experimental animal model, where murine salivary glands have been widely used in research by their similarities with human glands. Stereology is a tool that has to demonstrated to be valuable in biomedical researc h. Therefore, the objective was to realize an analogy between morphology, function and morpho-quantitative characteristics of the C57BL/6 mouse submandibular gland. Five male mice, C57BL/6, from 11 to 13 weeks old were used, with an average weight of 30 g. After seven days, the mice were euthanized and the samples were extracted. Then, these were processed following the conventional histological processing protocol and stained with H&E, Picrosirius Red, AA and PAS. Finally, the histological and stereological analysis of the samples was performed. In the glandular ducts the length density (LVcond), volume density (VVcond) and surface density (SVcond) were determined; whereas, in the acinar cells the density of number (NVcel) and the density of volume (VVcel) were evaluated. For each stereological variable the mean ± standard deviation was obtained. The histological study revealed no discrepancies as previously described. Descriptive statistical analysis revealed the following: LVcond = 220.02 ± 50.51 mm/mm3; VVcond = 50.48 ± 9.55 %; SVcond = 26.39 ± 5.45 mm2/mm3; NVcel = 168467.38 ± 91288.67 /mm3 and VVcel = 24.98 ± 6.22 %. From this study, it will be possible to conduct comparative experimental research analyzing quantitative results from those presented in this research. From this study, it will be possible to carry out comparative experimental research, analyzing quantitative results from those presented in this investigation.

Deep cervical fascia as an anatomical landmark of lingual lymph nodes: An anatomic and histologic study.

OBJECTIVES: We aimed to discuss the definition of lingual lymph nodes based on the deep cervical fascia anatomy. METHODS: A total of 11 cadavers were histopathologically evaluated. Specimens were dissected into serial stepwise cross-sections. The deep cervical fascia and lymph nodes were evaluated by staining the cross-sections with Elastica van Gieson and hematoxylin and eosin stains, respectively. The gross anatomy of the deep cervical fascia was evaluated in 1 cadaver after bilateral dissection. RESULTS: A single severely degenerated medial lingual lymph node (MLLN) was identified in the lingual septum of 1 cadaver. A single lateral lingual lymph node (LLLN) was identified in 1 cadaver, between the genioglossus and the hyoglossus. The superficial layer of deep cervical fascia (SLDF) was found to split into two layers encapsulating the submandibular gland. The deeper portion of this fascia was in close contiguity with the hyoglossus and formed the boundary between the mouth and the neck. The SLDF was found to be discontinuous with the area between the sublingual space and the submandibular gland. CONCLUSIONS: The SLDF could serve as an anatomical landmark for lingual lymph nodes, since it is considered to be the demarcating boundary during neck dissection. When lymph nodes that are located deeper than the SLDF were defined as lingual lymph nodes, 1 MLLN and 1 LLLN were identified.

Reduction Neck Lift: The Importance of the Deep Structures of the Neck to the Successful Neck Lift.

A description of the deep structures of the neck that are responsible for submandibular fullness and a systematic surgical approach to reduce them are presented. The structures susceptible to surgical management include the subplatysmal fat, inter-sternocleidomastoid origin fat, anterior belly of the digastric muscle, hyoid bone, submandibular gland and the tail of the parotid gland. A thorough analysis of the key anatomic landmarks of the young and attractive neck is detailed in resting and dynamic positions. A clinical classification of parotid reduction in the face lift/neck lift patient is also presented.

Management of the Submandibular Gland in Neck Lifts: Indications, Techniques, Pearls, and Pitfalls.

Neck contour deformities are common among patients who present for facial rejuvenation. A thorough physical examination and photographic analysis, including an upward view of the flexed neck, enable the surgeon to determine which structures should be treated. Common causes of neck concerns include hypertrophy of the subplatysmal fat, the anterior belly of the digastric muscle, and/or the submandibular salivary glands. Partial removal of the submandibular salivary glands requires advanced knowledge of subplatysmal anatomy and surgical expertise but can be performed safely and reliably to yield favorable results of neck rejuvenation.

Jaw Opening Decreases Window to the Deep Parotid Lobe.

To describe the relationship between jaw opening and access to the deep parotid window, we identified the following distances in 10 human skulls: symphysis to angle of mandible, mastoid tip to angle of mandible, angle of mandible to condylar process, and mastoid tip to condylar process. With the jaw closed and open, these distances were measured with 1 to 3 wooden blocks, each measuring 1 cm, between the upper and lower incisors. The triangular deep parotid area formed by the last 3 distances was calculated. A repeated measures analysis of variance showed a significant decrease in the deep parotid area with increasing interincisal distance ( P < .01). A generalized estimating equation model demonstrated a statistically significant decreasing area of the deep parotid window with increasing interincisal distance. These results suggest that nasal intubation may improve access to the parotid window.

Accessory Submandibular Salivary Gland Forming a "Horseshoe" With the Main Submandibular Salivary Gland: A Unique Variation.

Presence of accessory submandibular salivary gland (ASSG) is an extremely rare variation. Knowledge of its relations could be very useful to oral and maxillofacial surgeons, head and neck surgeons, and radiologists. During dissection classes, an ASSG was noted between the mylohyoid and hyoglossus muscles. The main submandibular salivary gland had superficial and deep parts. The deep part was narrow and measured about 5 cm. The lingual nerve passed between the superficial and deep parts. The accessory submandibular gland was situated below and parallel to the deep part of SSG. It also measured 5 cm. The ASSG had its own duct, which joined the duct of main gland. The ASSG and the deep part of the SSG were united at the lateral border of geniohyoid muscle to give a characteristic "horseshoe" appearance. The ASSG overlapped both lingual and hypoglossal nerves.

Quantitative Assessment of Thyroid, Submandibular, and Parotid Glands Elasticity With Shear-Wave Elastography in Children.

Tissue elasticity is becoming a more commonly used parameter in evaluation of parenchyma in inflammatory diseases. Considering the changes in the thyroid and salivary glands with adolescence, determination of mean elasticity ranges with a function of age is necessary to apply ultrasound elastography more widely in the pediatric population.The thyroid, submandibular, and parotid glands of 127 healthy volunteers (66 males, 61 females; mean age = 10.3 ± 3.9 years; range = 3-17 years) were evaluated with shear-wave elastography.The mean elasticity values for the thyroid, submandibular, and parotid glands were 14.6 ± 3.3, 11.8 ± 2.2, and 11.8 ± 2.6 kPa, respectively. There was a significant positive correlation between age and elasticity of the thyroid, submandibular, and parotid glands. There was a significant correlation between age and elasticity value of the thyroid gland adjusted for weight and height.This study provided the baseline quantitative elasticity measures of thyroid, submandibular, and parotid glands, which would be a reference for upcoming studies. In addition, an increase in elasticity value in thyroid gland as a function of age independent of change in weight and height was demonstrated.

Effects of biodegradable hydrogel spacer injection on contralateral submandibular gland sparing in radiotherapy for head and neck cancers.

Xerostomia is the most common late toxicity after head and neck radiation. We demonstrate injection of a hydrogel spacer anteriorly displacing the submandibular gland. This procedure enables reduced dose to the displaced submandibular gland in cadaveric models of oropharynx cancer treated with IMRT, with potential implications in reducing xerostomia risk.

Planimetric correlation between the submandibular glands and the pancreas: a postmortem ductographic study.

The salivary glands and pancreas have comparable anatomic and antigenic properties and can share common pathogenetic mechanisms involving toxic or autoimmune processes. The aim of this study is to assess the correlation in size between the normal submandibular glands and the pancreas. The study was based on human autopsy specimens of the pancreas, neck and oral base from 22 adults, both sexes (mean age, 57.9 years). The pancreatic and submandibular ducts were injected with a contrast medium, and the area of the salivary and pancreatic glandular ductograms was measured with the aid of software for quantification of visual information. Samples of tissue from the salivary glands and the pancreas were studied by means of light microscopy. A high correlation was found between the planimetric size of the pancreas and the submandibular glands (correlation coefficient 0.497 and 0.699 for the right and the left gland, respectively). This ratio was close to 5:1. There were no significant differences in size for the left vs. right submandibular gland (p = 0.39). The ductograms were significantly larger in size in males than in females (p < 0.001). This study has proven a positive correlation in planimetric size between the normal submandibular glands and pancreas, a result that is expected to have possible clinical implications in the long-term follow-up of patients with chronic pancreatitis.

Assessment of Lingual Concavities in Submandibular Fossa Region in Patients requiring Dental Implants-A Cone Beam Computed Tomography Study.

AIM: The present study was aimed at assessing the lingual concavities in the submandibular fossa region in patients requiring dental implants with the help of cone beam computed tomography (CBCT). MATERIALS AND METHODS: The present study included 140 patients who visited the department with the missing mandibular posterior teeth. CBCT images were obtained using planmeca machine. Cross sections of 1 mm of submandibular fossa in the region of 1st and 2nd molar were studied and Type I to III lingual concavities were analyzed by a radiologist. RESULTS: Type I lingual concavity (< 2 mm) was seen in 23%, type II (2-3 mm) in 62% and Type III (> 3 mm) in 15% of patients. The difference was significant (p < 0.05). Males had slightly higher mean ± S.D value at 1st molar (2.6 mm ± 0.94) and 2nd molar (2.8 mm ± 0.90) on the left side and (2.7 mm ± 0.92) at 1st molar and (2.9 mm ± 0.93) at 2nd molar on the right side. The difference was nonsignificant (p > 0.05). Females had mean ± S.D value at 1st molar (2.3 mm ± 0.90) and (2.5 mm ± 0.92) at 2nd molar on the left side and (2.4 mm ± 0.91) at 1st molar and (2.8 mm ± 0.93) at 2nd molar. The difference was nonsignificant (p > 0.05. The difference between both genders was statistically nonsignificant (p > 0.05). CONCLUSION: Type I bone is the best for placing an implant. The chances of complications are more in type II and III bone. CBCT provides necessary information before planning implant in the edentulous area. CLINICAL SIGNIFICANCE: Cone beam computed tomography (CBCT) is the best radiographic aid which is effective in delineating different types of bone in the mandibular posterior region.

Effect of Biochanin A versus 17ß estradiol in rat submandibular salivary gland.

The epigenetic nature of development mandates the observation of the effect of any exogenous substance, especially those with estrogenic activities, during critical phases of development. The submandibular gland (SMG) presents as a great model due to extensive postnatal development, and is known to be regulated and affected by hormones as well as growth factors. Herein, we observed postnatal development following low doses of Biochanin A (BCA) and 17ß estradiol (E2) in rats. The pups were randomly divided into four groups: control, BCA, E2, and dimethyl sulfoxide (DMSO), and euthanized at the 6th, 15th, 30th, and 60th postnatal days (PND). SMG morphogenesis was assessed. The nuclear expression of estrogen receptor beta (ERß) was evaluated immunohistochemically; ERß expression was up-regulated by BCA and down-regulated by E2. Similarly, caspase three gene expression, assessed by real time polymerase chain reaction was increased in the BCA group but decreased in the E2 group. A significant decrease in epidermal growth factor gene expression was noted at PND 30. The results presented by this study provide evidence that the effect of a postnatal exposure of the SMG to Biochanin A during development could be linked to sex hormone-dependent disorders.

Subplatysmal Necklift: A Retrospective Analysis of 504 Patients.

BACKGROUND: Improvement of neck contour is a primary goal of patients who seek rejuvenation of the face and neck. Subplatysmal structures, including fat, the digastric muscle, and the submandibular salivary glands (SMSGs), may contribute to the appearance of a disproportionately large neck. OBJECTIVES: The authors sought to evaluate the safety, effectiveness, and predictability of necklift combined with reshaping and repositioning of the subplatysmal structures. METHODS: The records of 504 patients were reviewed retrospectively. Surgical maneuvers for subplatysmal necklift were described comprehensively and supplemented with videos. The subplatysmal anatomy was detailed by means of 2 cadaver dissections. RESULTS: A total of 430 patients (85.3%) underwent subplatysmal necklift. The most commonly treated structures were fat (423 patients [83.9%]), the SMSGs (307 patients [60.9%]), and the digastric muscle (91 patients [18.1%]). The most common complications were weakness of the lower lip depressor (29 patients [5.7%]), followed by sialoma of the parotid gland (10 patients [2%]). No patients experienced subplatysmal hematoma. CONCLUSIONS: Subplatysmal necklift is a safe, effective, and reliable option for patients who desire improved cervical contour. LEVEL OF EVIDENCE: 4 Therapeutic.

[Topographic features of lingual nerve and its relationship with other anatomical structures in maxillolingual groove].

By surgical interventions in maxillolingual groove area one should consider anatomical variations and topography of vessels, glands ducts and lingual nerve to prevent their injury. At the Department of Operative Surgery and Topographic Anatomy of the First Moscow State Medical University named after I.M. Sechenov we carried out anatomical study on cadavers (men and women, n=30).The study revealed topographical features of the lingual nerve and its relationship to other anatomical structures in the maxillolingual groove. It was found out that at the level of the second molar (96%) lingual nerve "crosses" duct of submandibular salivary gland, at the level of the third molar lingual nerve is located under the duct and lateral to it, closer to the inner surface of the body of the mandible. At the level of the first molar lingual nerve is located above and medial to Wharton duct and passes along sublingual-lingual muscles (m.hyoglossus).

Imaging submandibular pathology in the paediatric patient.

A wide range of pathologies may arise from the submandibular space (SMS) or submandibular gland (SMG) in children. We review herein the normal anatomy of the SMS and describe the role of imaging in the evaluation of SMS lesions. A schematic approach for the categorisation of SMS pathology based on imaging characteristics is provided.

Should we use fingerbreadth measurements in submandibular gland surgery? A critical appraisal of the technique.

OBJECTIVES: Having observed variation in the breadth of surgeons' fingers whilst they are placing the incision for submandibular gland surgery, we aimed to examine this technique of incision siting, quantify the differences in fingerbreadths and consider any consequences of variability. METHODS: Surgeons trained in salivary gland surgery were questioned on their method of incision placement for submandibular gland surgery. The breadth of index and middle fingers were subsequently measured using Vernier calipers. RESULTS: The majority of surgeons use a measure of two fingerbreadths below the mandible in planning their approach to the submandibular gland. There is a significant difference in the size of surgeons' fingers, particularly between men and women (mean, 4.2 cm vs 3.6 cm). CONCLUSION: Fingerbreadth measurements are somewhat arbitrary, with significant inter-surgeon variability. However, based on the results of cadaveric studies, the findings indicate that the technique is safe for marking the incision in submandibular surgery.

Clarification of the terminology of the major human salivary glands: acinus and alveolus are not synonymous.

Discrepancies in the terminology of the major human salivary glands often appear in anatomical textbooks and tend to adversely affect student's learning experience in Microscopic Anatomy. The main culprit is the inconsistent description of the morphology of these glands secretory end pieces where "acinus" and "alveolus" are used interchangeably. The correct terminology originated from Malpighi (1687), repeated by Kölliker (1854), but over the years has been misinterpreted by prominent authors as a result of the nature of specimen preparation. This commentary is based on etymology, current standard light microscopy, research studies and consultation with experts. The overall objective of this publication is to recommend that textbooks should endeavour to modify the relevant descriptions about this terminology in their future editions. The most appropriate terminology for the major human salivary glands would be: (1) the parotid gland, entirely serous, should be called compound acinar glands; (2) the submandibular glands are mixed glands; their serous components are compound acinar while some of the mucinous areas are tubular with serous, crescents or demilunes, as acinar end pieces hence they should be named compound tubuloacinar glands; (3) the sublingual glands, mainly mucous glands with tubular shape, with small acinar end pieces that are serous crescents thence they should be called compound tubuloacinar glands.

[Volume measurements of human parotid and submandibular glands].

OBJECTIVE: To accurately measure the volume of normal human parotid and submandibular glands, establish the normal values of the volumes of the glands, and apply the technique in the diagnosis of swollen salivary glands of the patients with IgG4-related sialadenitis. METHODS: Two hundred and forty cases with normal parotid and submandibular glands who received CT examination were divided into 4 groups according to the age standards raised by the Society of Geriatrics Chinese Medical Association and WHO (2000) age standards . 3D CT images of parotid and submandibular glands were reconstructed by technique of volume rendering. Volumes of normal parotid and submandibular glands were measured and their normal values were analyzed. The volumes of swollen parotid and submandibular glands from 30 cases with IgG4-related sialadenitis were compared with the normal values. RESULTS: 3D images of parotid and submandibular glands were well established by volume rendering. The normal values(95%confidence interval, 95%CI) of CT volume of parotid gland were as follows: adolescent group of males: 16.993-20.975 cm(3), females: 13.908-16.696 cm(3); young group of males: 20.015-24.359 cm(3), females: 18.089-21.135 cm(3); middle-aged group of males: 28.638-35.122 cm(3), females: 19.588-22.474 cm(3); young elderly and elderly group of males: 28.792-35.082 cm(3), females: 28.783-34.909 cm(3). The normal values (95%CI) of submandibular gland were as follows: adolescent group of males: 7.202-8.852 cm(3), females: 6.494-8.126 cm(3); young group of males: 7.759-9.523 cm(3), females: 7.285-8.605 cm(3); middle-aged group of males: 8.423-10.177 cm(3), females: 7.905-9.309 cm(3); young elderly and elderly group of males: 8.310-10.510 cm(3), females: 7.003-8.203 cm(3). The volumes of parotid glands increased with age. but no significant change was found in those of submandibular glands. The volumes of the swollen glands from the patients with IgG4-related sialadenitis were significantly larger than those of the normal glands. CONCLUSION: Volumes of the parotid and submandibular glands could be definitely and quantitively measured by CT volume rendering. The established normal values in this study could be taken as the reference for the diagnosis of parotid and submandibular gland enlargement .