Anatomy of the fasciae and fascial spaces of the maxillofacial and the anterior neck regions

Anatomy of the Buccal Space: Surgical and Radiological Perspectives

Among the anatomical spaces in the head and neck area, the buccal space has often been studied in dental/oral surgery and cosmetic surgery because it contains the facial vessels, mandibular and facial nerves, and adipose tissue called the buccal fat pad. In addition, as the space can communicate with other spaces, it can be significant in infections. Although the anatomy of the buccal space has been reported in several studies, there have been discrepancies concerning its boundaries, and its communications have often been overlooked. The aim of this review is to examine the anatomy of buccal space including its boundaries, contents, continuity with adjacent spaces, and clinical significance. A literature review was performed on Google Scholar and PubMed. The literature has depicted the anterior, medial, and lateral boundaries more or less consistently, but descriptions of the posterior, superior, and inferior borders are controversial. The buccal space includes the facial arteries, veins, facial nerves, parotid duct, and lymph nodes, which can be described differently depending on definitions and the extent of the space. As it communicates with other anatomical spaces including the masticatory space, it can be a reservoir and a channel for infections and tumors. Buccal fat pads have various clinical applications, from a candidate for flap reconstruction to a target for removal for cosmetic purposes. This review will help understand the anatomy of the buccal space including its boundaries, residing structures, and communication with other spaces from surgical and radiological perspectives.

Sudden Death: A Practical Autopsy Approach to Unexplained Mediastinitis Due to Fatal Untreated Neck Infections-A Systematic Review

Neck infections are often prone to being underestimated and can manifest insidiously. The spread of infection can lead to translocation into thoracic areas, causing descending necrotizing mediastinitis (DNM). However, the application of the post-mortem approach in such cases is not well-described in the literature. A literature review was carried out according to the PRISMA methods. Nine papers were included in the final review, revealing different levels of involvement of neck layers that can be linked to different causes. Expertise with respect to the anatomy of the fasciae and spaces of the neck enables an understanding of the pathogenesis of DNM. However, a clear autoptic description was not provided in any of the articles. Therefore, we also employed a practical post-mortem approach to cases of death due to DNM. It is fundamental for pathologists to identify the exact head and neck structures involved. Providing dissectors with support from an otolaryngologist could be useful. This paper could help address such difficult cases.

Odontogenic infections in the antibiotic era: approach to diagnosis, management, and prevention

PURPOSE

The prevalence of odontogenic infections remains one of the highest in the world. If untreated, odontogenic infections can break through the limitation, disseminate to other organs or spaces, and cause high mortality rates. However, it is still difficult to rapidly target limited or disseminated infections in clinical practice. The type of disseminated odontogenic infections and the responsible bacteria have not been described in detail.

METHODS

Search databases (e.g., PubMed, MEDLINE, Web of Science, Embase) for reports published from 2018.1 to 2022.9. Use search strategies: ("odontogenic infections" OR "pulpitis" OR "periapical lesions" OR "periodontal diseases") AND ("disseminated infections" OR "complication").

RESULTS

Fourteen different types of disseminated odontogenic infections, most of which are polymicrobial infections, can spread through the body either direct or through hematogenous diffusion. Multiple microbial infections can be more invasive in the transmission of infection. Secondary infections are commonly associated with bacteria like Fusobacterium spp., Streptococcus spp., Peptostreptococcus spp., Prevotella spp., and Staphylococcus spp. Antibiotics with broad-spectrum activity are fundamental as first-line antimicrobial agents based on the microorganisms isolated from disseminated infections.

CONCLUSION

This review elaborates on the epidemiology, microorganisms, risk factors, and dissemination routes, and provides evidence-based opinions on the diagnosis, multidisciplinary management, and prevention of odontogenic infections for dentists and clinicians.

Mylohyoid Muscle: Current Understanding for Clinical Management-Part I: Anatomy and Embryology

The mylohyoid is one of the suprahyoid muscles, along with the geniohyoid, digastric, and stylohyoid muscles. It lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part I, the anatomy and embryology of the mylohyoid muscle will be reviewed in preparation for the clinical discussion in Part II.

Mylohyoid Muscle: Current Understanding for Clinical Management Part II: Clinical Anatomy, Radiology, and Surgical/Clinical Relevance

The mylohyoid is one of the suprahyoid muscles along with the geniohyoid, digastric, and stylohyoid muscles that lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part II, the radiology and clinical/surgical importance of the mylohyoid muscle will be discussed.

High-Resolution Phase-Contrast Tomography on Human Collagenous Tissues: A Comprehensive Review

Phase-contrast X-ray imaging is becoming increasingly considered since its first applications, which occurred almost 30 years ago. Particular emphasis was placed on studies that use this technique to investigate soft tissues, which cannot otherwise be investigated at a high resolution and in a three-dimensional manner, using conventional absorption-based settings. Indeed, its consistency and discrimination power in low absorbing samples, unified to being a not destructive analysis, are pushing interests on its utilization from researchers of different specializations, from botany, through zoology, to human physio-pathology research. In this regard, a challenging method for 3D imaging and quantitative analysis of collagenous tissues has spread in recent years: it is based on the unique characteristics of synchrotron radiation phase-contrast microTomography (PhC-microCT). In this review, the focus has been placed on the research based on the exploitation of synchrotron PhC-microCT for the investigation of collagenous tissue physio-pathologies from solely human samples. Collagen tissues' elasto-mechanic role bonds it to the morphology of the site it is extracted from, which could weaken the results coming from animal experimentations. Encouraging outcomes proved this technique to be suitable to access and quantify human collagenous tissues and persuaded different researchers to approach it. A brief mention was also dedicated to the results obtained on collagenous tissues using new and promising high-resolution phase-contrast tomographic laboratory-based setups, which will certainly represent the real step forward in the diffusion of this relatively young imaging technique.

Magnetic microspheres mimicking certain functions of macrophages: Towards precise antibacterial potency for bone defect healing

A variety of novel biomaterials have recently been developed to promote bone regeneration. However, the current biomaterials cannot accurately and effectively resist bacterial invasion. In this study, we constructed microspheres that mimic certain functions of macrophages as additives to bone repair materials, which can be manipulated as demanded to resist bacteria effectively and protect bone defect healing. Firstly, we prepared gelatin microspheres (GMSs) by an emulsion-crosslinking method, which were subsequently coated with polydopamine (PDA). Then, amino antibacterial nanoparticles obtained by a nanoprecipitation-self-assembly method and commercial amino magnetic nanoparticles were modified onto these PDA-coated GMSs to construct the functionalized microspheres (FMSs). The results showed that the FMSs possessed a rough topography and could be manipulated by a 100-400 ​mT static magnetic field to migrate directionally in unsolidified hydrogels. Moreover, in vitro experiments with near-infrared (NIR) showed that the FMSs had a sensitive and recyclable photothermal performance and could capture and kill Porphyromonas gingivalis by releasing reactive oxygen species. Finally, the FMSs were mixed with osteogenic hydrogel precursor, injected into the Sprague-Dawley rat periodontal bone defect of maxillary first molar (M1), and subsequently driven by magnetism to the cervical surface of M1 and the outer surface of the gel system for targeted sterilization under NIR, thus protecting the bone defect healing. In conclusion, the FMSs had excellent manipulation and antimicrobial performances. This provided us with a promising strategy to construct light-magnetism-responsive antibacterial materials to build a beneficial environment for bone defect healing.

Trends and Outcome of Aggressive Fascial Space Infections

Background: Odontogenic infections are common and self-limiting in most cases; however, they can lead to severe consequences, considerable morbidity and can even be fatal despite modern medical therapy. Patients and Methods: This retrospective study included patients with severe deep fascial space infections treated in the Maxillofacial Surgery Unit, General Surgery Department, Faculty of Medicine, Sohag University, Sohag Governorate, Egypt, and the Department of Oral and Maxillofacial Surgery, King Fahd Specialist Hospital (tertiary referral center), Burayda City, Qassim Province, Saudi Arabia, from June 2017 to June 2022. Results: This study included 296 patients, 161 (54.4%) males, 135 (45.6%) females. The fifth decade of life was the most common vulnerable age group. Forty-three percent of patients had diabetes mellitus, 26.6% were hypertensive, and 13.3% were on long-term steroid therapy. In 83% of patients, the offending tooth was identified but in 17% of patients no dental cause was identified. The lower third molar tooth was most commonly involved. Sixty-nine (23.3%) patients had submandibular space infections. Fifty-three (17.9%) patients had canine space infections. Thirty (10.1%) patients had submasseteric space infection. Twenty-eight (9.5%) patients had submental space infections. Twenty-three (7.8%) patients had combined infection of the submasseteric, submandibular, and pterygomandibular spaces, whereas 19 (6.4%) patients presented with Ludwig's angina. Conclusions: Odontogenic infections are common. The submandibular space is the most commonly affected single space. These infections could lead to lethal complications in immunocompromised patients, especially patients with diabetes mellitus. These infections require urgent surgical intervention to decrease hospital stays and avoid potentially lethal complications.

Principles of Treatment and Clinical-Evolutionary Peculiarities of Deep Cervical Spaces Suppurations-Clinical Study

As medical-surgical emergencies, regardless of the causal agent, deep cervical space suppurations are not only a diagnostic challenge, but also a therapeutic one. In some cases, in spite of proper therapeutic measures, extremely severe complications can develop. A 5-year retrospective study (2016-2020) was conducted on a group of 107 patients suffering from cervical suppurations, being hospitalized and treated in the ENT Clinic of the "Sf. Apostol Andrei" Emergency County Hospital of Galați. This research is a clinical-statistical study based on the experience of this ENT clinic and was carried out based on the analysis of the patients' medical records. Descriptive analysis' statistical methods of the data series collected from the clinical observation sheets were used, with the patients' informed consent for the processing of the aforementioned data, with the agreement of the Ethics Commission of the Emergency Clinical Hospital "Sf. Apostol Andrei" Galați and the College of Physicians Galați, România. The patients' clinical and multidisciplinary treatment features included in the study group are presented. The results highlight the clinical particularities of deep cervical space suppurations treatment, including under COVID-19 impact, or with other comorbidities, having consequences on the case mix index increase or directly on the costs, admittance duration and the clinical status of the patient at discharge. The conclusions of the clinical study are based on the fulfillment of the research objectives in terms of treatment and symptomatology of deep cervical space suppurations and under the impact of comorbidities (global health crisis and pandemic, triggering of comorbidities due to health care access difficulty in the context of anti-COVID-19 government-implemented measures and the infection-rate that overburdened the medical system in the early period of the pandemic). Individualized treatment of deep cervical space suppurations is recommended to be approached multidisciplinary. Of particular importance is early diagnosis combined with prompt and correctly instituted multidisciplinary treatment. In this context, an appropriate medical measure that we recommend is patient health education, as it was observed in the clinical study: most times, patients address medical services with advanced disease, hence the generally unfavorable prognosis and outcome (about 25% of patients develop unfavorable prognosis and 4% die).

A three-component model of the spinal nerve ramification: Bringing together the human gross anatomy and modern Embryology

Due to its long history, the study of human gross anatomy has not adequately incorporated modern embryological findings; consequently, the current understanding has often been incompatible with recent discoveries from molecular studies. Notably, the traditional epaxial and hypaxial muscle distinction, and their corresponding innervation by the dorsal and ventral rami of the spinal nerve, do not correspond to the primaxial and abaxial muscle distinction, defined by the mesodermal lineages of target tissues. To resolve the disagreement between adult anatomy and embryology, we here propose a novel hypothetical model of spinal nerve ramification. Our model is based on the previously unknown developmental process of the intercostal nerves. Observations of these nerves in the mouse embryos revealed that the intercostal nerves initially had superficial and deep ventral branches, which is contrary to the general perception of a single ventral branch. The initial dual innervation pattern later changes into an adult-like single branch pattern following the retraction of the superficial branch. The modified intercostal nerves consist of the canonical ventral branches and novel branches that run on the muscular surface of the thorax, which sprout from the lateral cutaneous branches. We formulated the embryonic branching pattern into the hypothetical ramification model of the human spinal nerve so that the branching pattern is compatible with the developmental context of the target muscles. In our model, every spinal nerve consists of three components: (1) segmental branches that innervate the primaxial muscles, including the dorsal rami, and short branches and long superficial anterior branches from the ventral rami; (2) plexus-forming intramural branches, the serial homolog of the canonical intercostal nerves, which innervate the abaxial portion of the body wall; and (3) plexus-forming extramural branches, the series of novel branches located outside of the body wall, which innervate the girdle and limb muscles. The selective elaboration or deletion of each component successfully explains the reasoning for the standard morphology and variability of the spinal nerve. Therefore, our model brings a novel understanding of spinal nerve development and valuable information for basic and clinical sciences regarding the diverse branching patterns of the spinal nerve.

The carotid sheath: Anatomy and clinical considerations

Objectives

The distinctive bilateral carotid sheaths (CS) reside in the neck region and form part of the deep cervical fasciae. Aspects of the CS anatomy are controversial, most notably its specific attachment sites and fascial makeup, which are key determinants for the spread of tumours and infections and surgical planning. This review aimed to organise the pertinent aspects relating to CS anatomy and pathology, explore their clinical relevance and highlight areas of disagreement in the literature.

Methods

A narrative review identified key papers relating to CS anatomy, histology, embryology, pathology and clinical and surgical significance using PubMed and Google Scholar. This was supported by a systematic review focused on the fascia forming the CS which was conducted using PubMed, Web of Science and Core Collection which yielded 22 papers.

Results

and Discussion: The CS surrounds the internal carotid artery, internal jugular vein, cranial nerves IX - XII, lymph nodes and nervous plexuses as they course from the jugular foramen superiorly down along into the mediastinum inferiorly. There are contradicting descriptions regarding the CS attachments at the extracranial skull base and within the mediastinum. Author descriptions of the CS fasciae are complex, varied and incongruent. Pathologies affecting the CS include malignancies of the nerves, vascular lesions and utilisation of the CS space as a corridor for the spread of deep neck infections.

Conclusion

This paper collates and presents pertinent anatomical and clinical aspects regarding the CS. A proper knowledge of the CS anatomy and structural relationships will optimise surgical approaches and orientation when operating within the region.

Clinical Presentation and Microbiological Profile of Deep Neck Space Infections in Different Age Groups

Deep neck space infection (DNI), is defined as infections in the deep fascia enclosing potential spaces of the neck. In the past the diagnosis and treatment of DNI have challenged. The health care personnel at all levels. The complex anatomy and the deep location of this region remains a big problem with significant risks of morbidity and mortality. The aim of this study is to analyse the difference in clinical presentation and microbiology of DNI in different age groups. Eighty two patients with DNI which were managed at the Department of Otorhinolaryngology, ABVIMS and Dr. Ram Manohar Lohia Hospital New Delhi, between November 2017 and March 2019 formed the basis of our prospective cross sectional observational study. We observed that DNI is a frequent and potentially life threatening condition in children and adults despite the use of antibiotics. For appropriate surgical management knowledge of complex spaces of the neck and their communication with the other spaces is necessary.

Metastasis to the lateral lingual lymph node located behind the submandibular gland: A case of squamous cell carcinoma of the tongue

Inconsistency in the definition of LLNs may be a hurdle in ensuring the accuracy of the evidence. Refinements in the classification of LLNs, based on the fascial anatomy and lymphatic vessels, are warranted.

Classification of postoperative edema based on the anatomic division with mandibular third molar extraction

Purpose

Several investigations have been performed for a postoperative edema after extraction, but the results have been controversial due to low objectivity or poorly reproducible assessments of the edema. The aim of this study was to suggest a classification and patterns of postoperative edema according to the anatomical division associated with extraction of mandibular third molar as a qualitative evaluation method.

Methods

This study was conducted forty-four mandibular third molars extracted and MRI was taken within 48 h after extraction. The postoperative edema space was classified by MRI (one anatomic component—buccinator muscle—and four fascial spaces—supra-periosteum space, buccal space, parapharyngeal space, and lingual space), and evaluated independently by two examiners. The inter-examiner reliability was calculated using Kappa statistics.

Results

The evaluation of buccinator muscle edema showed good agreement and the fascial spaces showed constant high agreement. The incidence of postoperative edema was high in the following order: supra-periosteum space (75.00%), buccinator muscle (68.18%), parapharyngeal space (54.55%), buccal space (40.91%), and lingual space (25.00%).

Conclusion

Postoperative edema could be assessed clearly by each space, which showed a different tendency between the anatomic and fascial spaces.

Minimally Invasive Intraoral Approach to Submandibular Lodge

The purpose of this study is to describe the Minimally Invasive Intraoral Approach (MIIA) performed on selected cases of abscesses and neck phlegmons of odontogenic origin when the infection has not spread beyond the inferior mandibular margin. This technique allows us to avoid cervicotomy by a direct approach to the abscess, draining it through the oral cavity. If the limits have already been crossed, then cervicotomy is necessary. The aim of the study is to show the surgical outcomes that we have achieved during a time span of two years, and to show the effectiveness of the MIIA and its results. We selected 66 patients with abscesses and neck phlegmons, from January 2018 to June 2020. Among these cases, five patients were excluded as it was not possible to recover medical records from database. The MIIA technique has been performed on 16 patients (26.2%) when a successful dental extraction and drainage of the submandibular lodge were accomplished. The patients who underwent the MIIA surgery have all perfectly healed and did not suffer from relapses during the follow-up. The results show the achievement of excellent healing, underlining the lower impact required by MIIA when compared to a more traditional approach through cervicotomy.

A glimpse of past, the temporo-buccinator band of Hovelaque, or the buccotemporal fascia of Zenker

Only a few studies published until now have described the fascial-tendinous complex between the temporal and the buccinator muscles, which will be reviewed here. In 1957, the "temporo-buccinator band" (TBB) was described by Gaughran, who gave credit to Hovelaque for its first description in 1914. Zenker coined it in 1955 as the "buccotemporal fascia" (BTF). A buccal extension of the temporal muscle tendon extends from the temporal crest of the mandible to insert within the buccinator muscle, anterior to the pterygomandibular raphe, and posterior to the parotid duct that perforates the buccinator. That tendinous expansion is embedded within the buccotemporal fascia, which is oriented antero-infero-medially and joins the buccopharyngeal fascia, forming the TBB/BTF, above which we find the buccal fat pad. The buccal nerve and artery cross this anatomical structure. The TBB/BTF is an additional layer closing the pterygomandibular space anteriorly, and its knowledge is needed for practitioners performing inferior alveolar nerve blocks.

Anatomical and histological study of the alar fascia

INTRODUCTION

The alar fascia remains one of the most variably described fascial structure in the human body. Much disagreement persists in the literature and mainstream anatomical texts about its anatomy, function, and clinical significance. It is generally described as a coronally oriented fascial sheet separating the retropharyngeal space anteriorly from the danger space posteriorly. The current study aimed to confirm the presence of the alar fascia and delineate its anatomical characteristics, connections, and potential function through gross dissection and microscopic analysis. Possible clinical and surgical implications are considered.

METHODS

Twelve (12) cadaveric necks were dissected and examined histologically. Smooth muscle (αSMA), nerve (S100 protein), and myosin proteins were identified immunohistologically to characterize the composition and possible functions of the alar fascia.

RESULTS

The alar fascia was found in all specimens spanning between the carotid sheaths. Morphologically, it was not a delamination or derivative of the prevertebral fascia. It extended from the base of the skull to the upper thoracic level (T2) where it fused with the visceral fascia. No midsagittal connection was found between the alar and visceral fasciae. Immunohistochemically, the alar fascia was positive in focal areas for αSMA and S100 proteins but negative for fast and slow myosin.

CONCLUSION

The alar fascia is an independent and constant coronal fascial layer between the carotid sheaths. It contains neurovasculature and may limit the spread of retropharyngeal infections into the thorax as well as facilitate normal physiological functions of the cervical viscera.

A closer examination of the retromandibular subparotid approach: Surgical technique and anatomical considerations with a special focus on the angular tract. A cadaveric study and a technical note

Several approaches have been described for the surgical management of condylar fractures. Although there is no consensus on the best surgical technique, the retromandibular approach appears to be the most common reported in the literature. This approach is traditionally performed via a retromandibular incision and a transparotid route. An alternative technique to this approach entails a subparotid passage with the gland lifted antero-superiorly and no intraglandular dissection. This modification has been designed to reduce the risk of direct injury of the facial nerve branches as well as the risk of post-operative salivary fistula. The purpose of this technical report was to provide a "step-by-step" description of the retromandibular subparotid approach as performed in our department with particular emphasis on the relevant anatomically critical structures.

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.

Frontiers in fascia research

Basic sciences are the backbone of every clear understanding of how the body is composed and how different structures and functions are connected with each other. It is obvious that there is a huge variability in human beings - not only in terms of the outer appearance such as measurements of height, weight, muscle mass and other physical properties, but also with respect to metabolic and functional parameters. This article highlights recent developments of research activities in the field of fascia sciences with a special emphasis on assessment strategies as the basis of further studies. Anatomical and histological studies show that fascial tissue is highly variable in terms of density, stiffness, and other parameters such as metabolic and humoral activity. Moreover, it encompasses nerves and harbours a system of micro-channels, also known as the primo vascular system. As ultrasound is a widely available method, its use is appealing not only for imaging of fascial structures, but also for thorough scientific analysis. Unlike most other imaging technologies, US has the advantage of real-time analysis of active or passive movements. In addition, other assessment methods for fascial tissue are discussed. In conclusion, fascial tissue plays an important role not only in functional anatomy, but also in evolutionary and molecular biology, sport, and exercise science as well as in numerous therapeutic approaches. A high density of nerves is found in fascial tissue. Knowledge of individual characteristics, especially by visualizing with ultrasound, leads to personalized therapeutic approaches, such as in pain therapy.