Morphological and ultrastructural features of the laryngeal mound of Egyptian Cattle Egret (Bubulcus ibis, Linnaeus, 1758).

BACKGROUND: According to our acknowledgment this is the first full anatomical description of the studied laryngeal mound of the Egyptian Cattle Egret (Bubulcus ibis, Linnaeus, 1758). This study was obtained with the aid of scanning electron microscopy (SEM) and histological techniques. Heads of ten healthy adult male Egyptian cattle egrets were used in this study. RESULTS: The laryngeal mound (Mons laryngealis) was a pear-shaped musculoskeletal elevation. It represented 20.55 and 67.87% of the total length of the oropharyngeal floor and the pharyngeal floor, respectively. By SEM view, the lateral aspect of the caudal third of the laryngeal mound had a serrated mucosal appearance, forming of 6-7 finger-like projections. Furthermore, the terminal part of the laryngeal mound (except the middle part) was bordered a transverse row of pyramidal-shaped papillae, which demarcated from the esophagus. Histologically, laryngeal salivary glands termed (cricoarytenoid salivary glands) of the laryngeal mound were simple tubular type and were arranged in one row within the lamina propria connective tissue close to the lamina epithelialis. Those glands were surrounded by abundant aggregation of lymphocytes, extended overlying the surface lining epithelium. The glottis within the laryngeal mound was supported by hyaline cartilages; dorsally by paired arytenoid cartilages, ventrolaterally by cricoid cartilage, and caudodorsally by procricoid cartilage. Two groups of intrinsic laryngeal skeletal muscles have connected the cartilages. The glandular epithelium of the laryngeal salivary glands and chondrocytes of the laryngeal cartilages showed strongly positive alcian blue reaction. CONCLUSIONS: The laryngeal mound shows certain features that are unique as an adaptation to lifestyles and bird's habitat.

Three-Dimensional Analysis of Human Laryngeal and Tracheobronchial Cartilages during the Late Embryonic and Early Fetal Period.

Laryngeal and tracheobronchial cartilages are present as unique U-shaped forms around the respiratory tract and contribute to the formation of rigid structures required for the airway. Certain discrepancies still exist concerning cartilage formation in humans. To visualize the accurate timeline of cartilage formation, tracheobronchial and laryngeal cartilages were 3D reconstructed based on serial tissue sections during the embryonic period (Carnegie stage [CS] 18-23) and early fetal period (crown rump length [CRL] = 35-45 mm). The developmental phases of the cartilage were estimated by histological studies, which were performed on the reconstructed tissue sections. The hyoid greater horns were recognizable at CS18 (phase 2). Fusion of 2 chondrification centers in the mid-sagittal region was observed at CS19 in the hyoid bone, at CS20 in the cricoid cartilage, and in the specimen with CRL 39 mm in the thyroid cartilage. Phase 3 differentiation was observed at the median part of the hyoid body at CS19, which was the earliest among all other laryngeal and tracheobronchial cartilages. Most of the laryngeal cartilages were in phase 3 differentiation at CS22 and in phase 4 differentiation at CS23. The U-shaped tracheobronchial cartilages with phase 2 differentiation covered the entire extrapulmonary region at CS20. Phase 3 differentiation started on the median section and propagates laterally at CS21. The tracheobronchial cartilages may form simultaneously during the embryonic period at CS22-23 and early fetal periods, similar to adults in number and distribution. The spatial propagation of the tracheal cartilage differentiation provided in the present study indicates that cartilage differentiation may have propagated differently on phase 2 and phase 3. This study demonstrates a comprehensible timeline of cartilage formation. Such detailed information of the timeline of cartilage formation would be useful to improve our understanding of the development and pathophysiology of congenital airway anomalies.

Anatomic and histologic analysis of paca larynx (Cuniculus paca, Linnaeus 1766) / [Análise anatômica e histológica da laringe da paca (Cuniculus paca, Linnaeus 1766)]

Paca (Cuniculus paca) has encouraged research as an experimental model both in the human medicine and veterinary, as well as the economic exploitation of its meat cuts, which favored its zootechnical use. There are no anatomical, microscopic descriptions and measurements of the larynx in this rodent. Eight pacas were dissected from the wild animal's sector of the Faculty of Agricultural and Veterinary Sciences of the University of the State of São Paulo. The larynx was observed located in the ventral region of the neck, ventral to the esophagus, connecting the pharynx to the trachea, with cylindrical and irregular shape. Laryngeal cartilages (epiglottic, thyroid, cricoid and arytenoid) are interconnected and have different shapes. Thyroid showed greater length and width, compared to the others. Laryngeal cartilages were submitted to histological processing and stained with hematoxylin-eosin and Masson's trichrome. The epiglottic cartilage was stained with toluidine blue. Laryngeal cartilages thyroid, cricoid and the lower portion of the arytenoids are of hyaline origin and, in contrast, the epiglottis and the upper portion of the arytenoids are elastic. This latter cartilage demonstrated taste buds. The results will be able to auxiliate in veterinary care and as well as the conservation programs for this rodent.(AU)

A paca (Cuniculus paca) tem encorajado inúmeras pesquisas, tornando-a modelo experimental tanto em humanos como na veterinária, além da exploração econômica de seus cortes cárneos, que favoreceu diretamente sua importância zootécnica. Não há descrições anatômicas, microscópicas e mensurações da laringe desse roedor. Foram dissecadas oito laringes de pacas, provenientes do setor de Animais Silvestres da Faculdade de Ciências Agrárias e Veterinárias - Universidade Estadual Paulista. Observou-se que a laringe localiza-se na região ventral do pescoço, ventral ao esôfago, conectando a faringe à traqueia, possuindo formato cilíndrico e irregular. As cartilagens laríngeas (epiglote, tireóide, cricóide e aritenóidea) são interligadas e possuem formatos variados. A cartilagem tireóide demonstrou-se maior em comprimento e largura, comparativamente às demais. As cartilagens laríngeas foram submetidas a processamento histológico e coradas em hematoxilina-eosina e tricrômio de Masson. A cartilagem epiglote foi corada em azul de toluidina. As cartilagens laríngeas tireóide, cricóide e a porção inferior das aritenóides são de origem hialina; em contrapartida, a epiglote e a porção superior das aritenóides, de origem elástica. Esta última cartilagem demonstrou corpúsculos gustativos. Os resultados poderão auxiliar tanto nos atendimentos veterinários quanto nos programas de conservação desse roedor.(AU)

CT-based assessment of laryngeal fracture patterns and associated soft tissue abnormality.

OBJECTIVE: Acute traumatic injuries to the larynx, including fractures of the hyoid bone, cricoid, and thyroid cartilage, are uncommon injuries. The purpose of this study was to assess fracture and soft tissue patterns associated with laryngeal trauma. METHODS: This was a retrospective review of patients with laryngeal fractures who presented to two level I trauma centers and underwent CT imaging. Imaging findings, including fractures of the cartilaginous structures of the larynx and hyoid bone, and soft tissue abnormalities including focal hematoma, edema with non-focal hemorrhage, and additional penetrating injuries were recorded. Frequencies of fracture patterns were recorded. RESULTS: Thyroid cartilage fractures were most frequently observed occurring in 45/55 patients, followed by cricoid fractures in 13/55 patients. Hyoid fractures were encountered in 8/55 patients. Multi-site fractures were observed in 12/55 patients with thyroid-cricoid fractures occurring in 8/12 patients, followed by thyroid-hyoid fractures in 2/12 patients. Most multi-site fractures occurred in association with focal supraglottic hematomas (10/12), supraglottic edema and non-focal hemorrhage (11/12), and focal subglottic hematoma (5/12). All 13 cricoid fractures occurred with either focal supraglottic hematoma (7), focal subglottic hematoma (4), or edema with non-focal hemorrhage (13). CONCLUSIONS: Thyroid cartilage fractures were the most frequently encountered fracture, followed by cricoid cartilage fractures. Cricoid fractures always occurred with soft tissue abnormalities. Recognition of fracture patterns in the setting of laryngeal trauma and associated patterns of soft tissue injury is important for practicing radiologists for early diagnosis of these conditions and reduction of associated morbidity. KEY POINTS: • Acute fractures to the larynx may be isolated fractures or occur as multi-focal fractures. • Thyroid cartilage fractures are the most frequent fractures followed by cricoid cartilage fractures. • Cricoid cartilage fractures always occurred in association with soft tissue abnormalities.

Development of the chondrocranium of two caiman species, Caiman latirostris and Caiman yacare.

Little is known about the embryonic development and variation of the chondrocranium in Crocodylia and there are no works on any Caiman species. Due to the importance of cranial features in the systematics of this clade, investigating the development of the skull in embryonic stages is essential. In this study, we present for the first time the development of the cartilaginous skull of two extant Caiman species. Anatomical descriptions of the embryonic chondrocranium of Caiman latirostris and Caiman yacare were made, paying special attention to their inter- and intraspecific variation. For this purpose, pre-hatching ontogenetic cranial series of these two caiman species were prepared with a double staining and diaphanization technique. The main differences with other crocodylian species were observed in the palatoquadrate, and interspecific variation within the genus was recorded in the hyobranchial apparatus and larynx. Some characters may be distinctive of Caiman (posterior and ventral surface of the otic process of the palatoquadrate articulated with the dorsal process of the columella auris, and otic process articulated with the lateral wall of the auditory capsule), Alligatoridae (presence of an epiphanial foramen) or C. latirostris and C. yacare (Corpus hyoidei with different number and position of foramina and different shapes of its anterior contour and anterior and posterior notch, different degrees of broadening of the distal end of the Cornu branchiale I, and presence/absence of a notch in the posteroventral surface of the cricoid). Homologies of the elements belonging to the hyobranchial apparatus could not be confirmed. As in other tetrapods the trachea consists of incomplete cartilaginous rings. Morphological changes and dissimilarities found in this study are useful as a context to start studying phylogenetic constraints. Moreover, in a heterochronic context, variations may be involved.

Moffett's muted mules: the science of laryngology in the art of war.

BACKGROUND: Mules and other equine species have been used in warfare for thousands of years to transport goods and supplies. Mules are known for 'braying', which is disadvantageous in warfare operations. This article explores the fascinating development of surgical techniques to stop military mules from braying, with particular emphasis on the key role played by the otolaryngologist Arthur James Moffett in devoicing the mules of the second Chindit expedition of World War II. METHOD: The PubMed database (1900-2017) and Google search engine were used to identify articles related to devoicing mules in the medical and veterinary literature, along with information and images on the Chindit expedition. RESULTS: This paper reviews the surgical techniques aimed at treating braying in mules, ranging from ventriculectomy and arytenoidectomy to Moffett's approach of vocal cordectomy. CONCLUSION: Moffett's technique of vocal cordectomy provided a quick, reproducible and safe solution for devoicing mules. It proved to be advantageous on the battlefield and demonstrated his achievements outside the field of medicine.

Management of Laryngotracheal Trauma: A Five-Year Single Institution Experience.

INTRODUCTION: Laryngotracheal trauma is a rare life-threatening emergency that requires early identification and immediate intervention. Here, we present 26 patients with laryngotracheal trauma from a tertiary hospital in India. The aim was to describe the clinical presentation and management of laryngotracheal trauma patients. MATERIALS AND METHODS: This was a retrospective study of laryngotracheal trauma patients treated between January 2011 and March 2016. Patients who presented with a breach in the laryngotracheal framework were included, while those who had penetrating neck injuries superficial to strap muscles/platysma, burn injuries, caustic ingestion, or endotracheal injuries were excluded from the study. RESULTS: Of 253 patients with neck injury, 26 (23 adults, three children; 21 males, five females; age range, 5-60 years) presented with a breach in the laryngotracheal framework (15 blunt neck-trauma patients and 11 penetrating neck-trauma patients). The most common cause of neck injury was road traffic accidents, seen in 12 patients (46.2%). Computed tomography (CT) was performed in all blunt trauma cases and in four patients with penetrating trauma. All penetrating trauma patients underwent neck exploration. Twelve blunt trauma patients (46.1%) were managed conservatively, while three (11.5%) required surgical intervention. The most common neck exploration finding noted in patients with a penetrating injury was fracture of the thyroid cartilage, which was seen in eight patients (30.8%). Twenty patients (76.9%) had a normal voice, five patients (19.2%) had a hoarse voice, and one patient (3.8%) had a breathy voice post treatment. CONCLUSION: Early intervention of laryngotracheal trauma is crucial. The role of a CT scan is essential in decision making in blunt trauma cases.

Is the diagnosis of calcified laryngeal cartilages on panoramic radiographs possible?

PURPOSE: Detecting laryngeal cartilages (triticeous and thyroid cartilages) on panoramic radiographs is important because they may be confused with carotid artery calcifications in the bifurcation region, which are a risk factor for stroke. This study assessed the efficiency of panoramic radiography in the diagnosis of calcified laryngeal cartilages using cone-beam computed tomography (CBCT) as the reference standard. MATERIALS AND METHODS: A total of 312 regions (142 bilateral, 10 left, 18 right) in 170 patients (140 males, 30 females) were examined. Panoramic radiographs were examined by an oral and maxillofacial radiologist with 11 years of experience. CBCT scans were reviewed by 2 other oral and maxillofacial radiologists. The kappa coefficient (κ) was calculated to determine the level of intra-observer agreement and to determine the level of agreement between the 2 methods. Diagnostic indicators (sensitivity, specificity, accuracy, and false positive and false negative rates) were also calculated. P values <.05 were considered to indicate statistical significance. RESULTS: Eighty-two images were re-examined to determine the intra-observer agreement level, and the kappa coefficient was calculated as 0.709 (P<.05). Statistically significant and acceptable agreement was found between the panoramic and CBCT images (κ=0.684 and P<.05). The sensitivity, specificity, diagnostic accuracy rate, the false positive rate, and the false negative rate of the panoramic radiographs were 85.4%, 83.5%, 84.6%, 16.5%, and 14.6%, respectively. CONCLUSION: In most cases, calcified laryngeal cartilages could be diagnosed on panoramic radiographs. However, due to variation in the calcifications, diagnosis may be difficult.

Is the diagnosis of calcified laryngeal cartilages on panoramic radiographs possible?

PURPOSE: Detecting laryngeal cartilages (triticeous and thyroid cartilages) on panoramic radiographs is important because they may be confused with carotid artery calcifications in the bifurcation region, which are a risk factor for stroke. This study assessed the efficiency of panoramic radiography in the diagnosis of calcified laryngeal cartilages using cone-beam computed tomography (CBCT) as the reference standard. MATERIALS AND METHODS: A total of 312 regions (142 bilateral, 10 left, 18 right) in 170 patients (140 males, 30 females) were examined. Panoramic radiographs were examined by an oral and maxillofacial radiologist with 11 years of experience. CBCT scans were reviewed by 2 other oral and maxillofacial radiologists. The kappa coefficient (κ) was calculated to determine the level of intra-observer agreement and to determine the level of agreement between the 2 methods. Diagnostic indicators (sensitivity, specificity, accuracy, and false positive and false negative rates) were also calculated. P values < .05 were considered to indicate statistical significance. RESULTS: Eighty-two images were re-examined to determine the intra-observer agreement level, and the kappa coefficient was calculated as 0.709 (P < .05). Statistically significant and acceptable agreement was found between the panoramic and CBCT images (κ=0.684 and P < .05). The sensitivity, specificity, diagnostic accuracy rate, the false positive rate, and the false negative rate of the panoramic radiographs were 85.4%, 83.5%, 84.6%, 16.5%, and 14.6%, respectively. CONCLUSION: In most cases, calcified laryngeal cartilages could be diagnosed on panoramic radiographs. However, due to variation in the calcifications, diagnosis may be difficult.

Different Patterns of Cartilage Mineralization Analyzed by Comparison of Human, Porcine, and Bovine Laryngeal Cartilages.

Laryngeal cartilages undergo a slow ossification process during aging, making them an excellent model for studying cartilage mineralization and ossification processes. Pig laryngeal cartilages are similar to their human counterparts in shape and size, also undergo mineralization, facilitating the study of cartilage mineralization. We investigated the processes of cartilage mineralization and ossification and compared these with the known processes in growth plates. Thyroid cartilages from glutaraldehyde-perfused male minipigs and from domestic pigs were used for X-ray, light microscopic, and transmission electron microscopic analyses. We applied different fixation and postfixation solutions to preserve cell shape, proteoglycans, and membranes. In contrast to the ossifying human thyroid cartilage, predominantly cartilage mineralization was observed in minipig and domestic pig thyroid cartilages. The same subset of chondrocytes responsible for growth plate mineralization is also present in thyroid cartilage mineralization. Besides mineralization mediated by matrix vesicles, a second pattern of cartilage mineralization was observed in thyroid cartilage only. Here, the formation and growth of crystals were closely related to collagen fibrils, which served as guide rails for the expansion of mineralization. It is hypothesized that the second pattern of cartilage mineralization may be similar to a maturation of mineralized cartilage after initial matrix vesicles-mediated cartilage mineralization.

Trauma to the hyoid bone and laryngeal cartilages in hanging: review of forensic research series since 1856.

Since 1856 lots of forensic reports, concerning trauma to the hyoid bone and laryngeal cartilages in hanging, have been published. Differences in percentage of injured neck complexes ranged from 0 to 83.3%. Simple arguments suggest that the reason for discrepancy is difference in scientific approach (retro- or prospective) and use of various research methods. Comparative analysis of widely used techniques shows considerable variety in their effectiveness. Plain radiography and palpatory method have fairly low sensitivity (33-60% for different elements of the neck complex) with relatively high specificity (89-98.5%). Reported sensitivity of postmortem CT in identification of different lesions (including fractures) in trauma victims for the head/neck region is higher than 53% in different series with possible false-positive findings. In clinical setting the whole-body CT (pan-scanning) in blunt trauma patients showed sensitivity for head and neck injuries at the level of 84.6%, and specificity - 98.9% (Stengel et al., 2012 [68]). Only complete preparation allows to identify all the damages to the laryngopharynx framework, to avoid false diagnostics and ascertain the exact location, morphology, mechanism and intravital nature of the neck trauma. Currently complete preparation can be regarded as the method of "gold standard". Use of this method shows the frequency of discovered injuries in hanging to be about 70% of cases. In practical use, one should consider radiological techniques and palpation as preliminary and orienting methods (rather excluding, than revealing anterior neck trauma).

A Case of Horizontal Partial Laryngectomy for Laryngeal Trauma / 대한이비인후과학회지

Laryngeal trauma is rare compared to other head and neck traumas, but it occurs, it can be life threatening. As for treatment, a laryngeal fracture that involves displacement of cartilage or extensive injury requires appropriate surgical treatments. For severe laryngeal fractures, conservative management is usually preferred with placing a stent to prevent laryngeal stenosis. But the downside of placing stents in the larynx includes the risk of granulation and infection. In this report, the authors describe a 35-year-old patient, who was diagnosed with blunt laryngeal trauma and treated by Horizontal partial laryngectomy. The patient's post-operative breathing and voice were fair, and airway stenosis did not occur afterwards.

Early recognition and management of laryngeal fracture: a case report.

BACKGROUND: Laryngeal fracture is a rare condition that can lead to significant problems with airway patency, voice production, and swallowing. Conflict in the literature exists regarding the most suitable way to manage this injury. CASE REPORT: We present the case of a 29-year-old Caucasian man who sustained a displaced fracture of the thyroid cartilage due to blunt trauma. He reported no swallowing, breathing, or voice problems after 1 year, and his recovery can be attributed to the early recognition and proper management of his condition. CONCLUSION: This case illustrates the importance of ensuring a high level of suspicion for laryngeal fracture in the acute trauma patient. Early identification of this injury allows early intervention that not only protects the airway but also improves long-term voice and airway outcomes.

Special pattern of endochondral ossification in human laryngeal cartilages: X-ray and light-microscopic studies on thyroid cartilage.

Endochondral ossification is a process that also occurs in the skeleton of the larynx. Differences in the ossification mechanism in comparison to growth plates are not understood until now. To get deeper insights into this process, human thyroid cartilage was investigated by the use of X-rays and a series of light-microscopic stainings. A statistical analysis of mineralization was done by scanning areas of mineralized cartilage and of ossification. We detected a special mode of endochondral ossification which differs from the processes in growth plates. Thyroid cartilage ossifies very slowly and in a gender-specific manner. Compared with age-matched women, bone formation in thyroid cartilage of men is significantly higher in the age group 41-60 years. Endochondral ossification is prepared by internal changes of extracellular matrix leading to areas of asbestoid fibers with ingrowing cartilage canals. In contrast to growth plates, bone is deposited on large areas of mineralized cartilage, which appear at the rims of cartilage canals. Furthermore, primary parallel fibered bone was observed which was deposited on woven bone. The predominant bone type is cancellous bone with trabeculae, whereas compact bone with Haversian systems was seldom found. Trabeculae contain a great number of reversal and arresting lines meaning that the former were often reconstructed and that bone formation was arrested and resumed again with advancing age. It is hypothesized that throughout life trabeculae of ossified thyroid cartilage undergo adaptation to different loads due to the use of voice.