Effects of ageing on the insertion zones of the human vocal fold

Configuration of elastin fibers in the intra- and extra-capsule ligaments of the elderly cricoarytenoid joint

PURPOSE

To define the localization and configuration of the elastic fibers of the cricoarytenoid ligament (CAL) and their relationship with the cricoarytenoid joint (CAJ) capsule.

METHODS

Twenty-four CAJs from twelve cadavers were analyzed using Verhoeff-Van Gieson staining, and immunohistochemistry methods. This is a prospective study.

RESULTS

The CAL was classified into two parts: an extra-capsular anterior-CAL and an intra-capsular posterior-CAL. The both parts contained rich elastic fibers. The elastic fibers of the anterior-CAL were orientated in both anterior-posterior and superior-inferior directions and under a relaxation status, whereas the elastic fibers of the posterior-CAL were arranged in a lateral-medial direction and under a taut status.

CONCLUSIONS

This study defined the fine configuration of the CAL, particularly its elastic fibers, which may help us to better understand the biomechanics of the CAJ motions, and differential diagnosis of CAJ disorders. The results of the study re-confirm that the P-CAL is the key posterior-lateral passive force to limit the mobility of the muscular process of the arytenoid cartilage and stabilize the CAJ, whereas the A-CAL may protect the CAJ from an over superior-lateral-posterior motion.

LEVEL OF EVIDENCE

H/A.

Description and evolution of the larynx of the Physalaemus olfersii species group, with remarks on the laryngeal anatomy of the P. cuvieri clade (Amphibia: Anura: Leiuperinae)

The anuran larynx is an organ of great evolutionary interest because it impacts male reproductive success in courtships. However, little is known about the diversity of the larynx's anatomy, evolutionary history and systematics importance. Here, we describe and compare the anatomy of the larynx of 10 Physalaemus species of the P. cuvieri clade, focusing on the P. olfersii species group. We also reconstructed the ancestral states and tested the phylogenetic signal for the anatomical features. In all the species, the larynx has a general globular shape with the arytenoid cartilages covering almost its entire dorsal surface, while the anterior process of the cricoid cartilages covers most of the ventral surface. The size of the secondary fibrous mass, the thickness of the vocal membrane, and the attachment position of the vocal membrane's free edge considerably differ among the species. Moreover, only four species of a single clade in the P. olfersii species group have the primary fibrous mass well-developed with a suspended region in the dorsolateral passage. We found a significant phylogenetic signal for all these characters. Ancestral reconstructions pointed to reduction tendencies in the thickness of the vocal membrane and the size of the secondary fibrous mass, and a shift of the ventral attachment of the vocal membrane, increasing the angle of its free edge along the phylogeny. This latter trait can diagnose the entire Physalaemus olfersii group, which has the ventral ends of the arytenoids positioned posteriorly, giving this group the steepest angles for the vocal membrane's free edge in relation to the frontal plane. Based on our results, the larynges can contribute to the Physalaemus olfersii species group's systematics and could be elucidative to understand the evolution of the genus. High levels of anatomical and bioacoustical complexity and diversity observed in the group support the expected correlation between vocal anatomy and bioacoustical signal.

Voice and Respiratory Characteristics of Men and Women Seeking Treatment for Presbyphonia

BACKGROUND AND OBJECTIVES

Impaired respiratory function could potentially explain why some older speakers experience voice-related handicap whereas others do not, despite presenting with similar age-related laryngeal characteristics. The objectives of this study were therefore to (1) describe voice and respiratory function across men and women in a sample of treatment-seeking patients with presbyphonia; (2) assess how respiratory function differed from the general elderly population, based on normative data; and 3) discuss how respiratory function may play a role in the development of voice symptoms across men and women.

METHODS

Twenty one participants with presbyphonia underwent respiratory assessments (spirometry and respiratory muscle strength testing) in addition to standard of care voice assessments. Respiratory variables included forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), FEV₁/FVC, maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP).

RESULTS

Voice features were consistent with the diagnosis of presbyphonia and values did not different significantly between males and females, although some trends were noted. Regarding respiratory variables, one-third of the participants (n = 7) presented with FVC and FEV₁ less than 80% of predicted, and 57% (n = 12) were <90% of predicted. Nine percent of the males (n = 1) and none of the females had a MIP below the lower limit of normal (LLN) expected for their age, sex, and weight. Eighteen percent of the males (n = 2) and 20% of the females (n = 2) fell below the LLN for MEP.

CONCLUSION

Our sample of participants with presbyphonia included a non-negligible proportion of patients with decreased percent predicted values of FVC and FEV₁, and with respiratory muscle strength (MEP) below the LLN. Standardized values of pulmonary function were not different across sexes, indicative of a similar respiratory health. However, a lower raw pulmonary function and respiratory muscle strength in women may compound laryngeal changes and have an impact on perceived voice-related handicap. Together, findings warrant further studies to explore the impact of decreased respiratory function on voice and, ultimately, on the response to voice therapy in patients with presbyphonia.

How Does Our Voice Change as We Age? A Systematic Review and Meta-Analysis of Acoustic and Perceptual Voice Data From Healthy Adults Over 50 Years of Age

Purpose Approximately 30% of adults over the age of 50 years present with altered vocal function. Our understanding of how these changes manifest acoustically and perceptually is derived from relatively modest-sized studies using a diversity of tools. Voice changes can arise from the onset of disease or disorder, but also age-related physiological changes, which may not reflect pathology as such. Here, we bring together data on acoustic, perceptual, and instrumental assessments (electroglottography), with the aim of gaining a better understanding of the changes occurring across these measurement domains. We consider these changes in the context of different acoustic features, software programs, and perceptual protocols. Method Studies of voice function in healthy older adults over the age of 50 years were sought. Literature was systematically searched with 746 abstracts reviewed. Forty-seven studies were included in the review. A meta-analysis of included studies compared voice acoustic parameters between sex and age. Sixteen acoustic parameters collected from 1,475 participants were analyzed in the meta-analysis. These included some previously unpublished analyses using data provided by authors of included studies. Results Data from the systematic review suggest that older individuals are perceived to present with higher overall scores of dysphonia and roughness, breathiness, strain, and instability. Acoustically, males have significantly higher scores on measures of perturbation, including noise-to-harmonic ratio and absolute jitter. The meta-analysis outcomes suggest that participants aged 80-89 years produce significantly higher fundamental frequency, jitter percent, shimmer percent, and shimmer in decibels compared to participants aged 60-69 years and a significant increase in relative average perturbation, jitter percent, and shimmer in decibels compared to participants aged 70-79 years. Limited data were available comparing acoustic measures using the same acoustic software. Conclusions Variations in fundamental frequency and frequency and amplitude perturbation increase as healthy adults age. It was difficult to draw definitive conclusions based on existing literature due to variability in hardware used, limited descriptions of study cohorts, or missing data from statistical analysis. Supplemental Material https://doi.org/10.23641/asha.11868663.

The prognostic value of anterior commissure involvement in T1 glottic cancer: A systematic review and meta-analysis

OBJECTIVE

The anterior commissure is considered a laryngeal subsite, but it is not taken into account in the current T-staging system. The impact of anterior commissure involvement (ACI) on the oncologic outcomes of T1 glottic tumors has not been well defined and remains controversial. The aim of this study was to assess the influence of ACI in the prognosis of T1 glottic tumors.

METHODS

A systematic review and meta-analysis of observational studies was performed by including studies published up to July 2019. Studies were selected if they had investigated the local control rate (LCR) at 5 years of clinical stage I (T1 and N0) glottic squamous cell carcinoma with and without ACI. The difference in LCR at 5 years between T1 glottic tumors without and with ACI was evaluated.

RESULTS

The meta-analysis showed that the difference in LCR at 5 years between T1 glottic tumors without and with ACI is 12% (95% confidence interval: 8%-16%, p < 0,0001, I² = 34.81%).

CONCLUSIONS

Our study pointed out that the anterior commissure involvement is a negative prognostic factor in LCR at 5 years for T1 glottic tumors. Our results suggest the need to consider ACI in the T staging of glottic tumors. Laryngoscope, 130:1932-1940, 2020.

Mechanical, Cellular, and Proteomic Properties of Laryngotracheal Cartilage

The larynx sometimes requires repair and reconstruction due to cancer resection, trauma, stenosis, or developmental disruptions. Bioengineering has provided some scaffolding materials and initial attempts at tissue engineering, especially of the trachea, have been made. The critical issues of providing protection, maintaining a patent airway, and controlling swallowing and phonation, require that the regenerated laryngotracheal cartilages must have mechanical and material properties that closely mimic native tissue. These properties are determined by the cellular and proteomic characteristics of these tissues. However, little is known of these properties for these specific cartilages. This review considers what is known and what issues need to be addressed.

How Age and Frequency Impact the Thyroid Cartilages of Professional Singers

OBJECTIVES/HYPOTHESIS

Young professional singers can easily reach very high pitches. In contrast, older singers often complain that they have to exert substantially more laryngopharyngeal force to reach the same high pitch compared with their earlier years. Various factors such as the property changes of the mucosa and ossification that impact the singing apparatus were suggested as explanations in the literature. The aim of this study was to analyze thyroid deformation-and thereby stiffness indirectly-during singing as a potential reason for this phenomenon.

STUDY DESIGN

Prospective study.

METHODS/DESIGN

We examined 44 female professional singers. High-resolution computed tomography scans were performed during singing at the fundamental mean speaking frequency and the first and second octaves above it. Digital Imaging and Communications in Medicine scan data were rendered and visualized 3-dimensionally using MIMICS software. By superimposition of the different 3-dimensional images, different positions of the thyroid were visualized. The distance from the posterior border of the thyroid was measured in all the examinations.

RESULTS

All laryngeal cartilages could be three-dimensionally visualized. The magnitude of the thyroidal deformation significantly depends on pitch and significantly correlates with age (r² = 0.7, P < 0.001).

CONCLUSIONS

The thyroid cartilage is flexible and its formability is especially important during singing. At higher pitches, the cartilage was more deformed. The larynx in older singers showed less thyroid cartilage deformation.

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.

Sulfated glycosaminoglycans in human vocal fold lamina propria

Introduction

The distribution, concentration and function of glycosaminoglycans in the various vocal fold tissues are still unclear.

Objective

To evaluate the distribution and concentration of sulfated glycosaminoglycans in different layers of the human vocal fold according to gender and age.

Methods

We used 11 vocal folds obtained from cadavers (7 men and 4 women) with no laryngeal lesion, less than 12 h after death, and aged between 35 and 98 years. The folds underwent glycosaminoglycans extraction from the cover and ligament, and post-electrophoresis analysis. Data were compared according to the layer, age and gender.

Results

The concentration of dermatan sulfate was significantly higher in all layers. No differences were observed in the total concentrations of glycosaminoglycans in layers studied according to gender. It is significantly lower in the cover of individuals aged below 60 years.

Conclusion

Dermatan sulfate, chondroitin sulfate, and heparan sulfate were observed in the human vocal folds cover and ligament of both genders, with the concentration of dermatan sulfate being significantly higher in all layers. Glycosaminoglycans concentration on the cover is significantly lower in individuals below 60 years compared with elderly.

Alterations in extracellular matrix composition in the aging larynx

OBJECTIVE

To study by immunohistochemistry the alterations of collagens I, III, IV, and V and elastin in the aging process of the human larynx.

STUDY DESIGN

Cadaver study.

SETTING

Universidade Estadual Paulista, Botucatu Medical School, São Paulo State University (UNESP), Brazil.

SUBJECTS AND METHODS

Thirty vocal folds were obtained at autopsy from 10 adult men (aged 30 to 50 years) and 20 geriatric men (10 aged 60 to 75 years and 10 aged >75 years). Mid membranous vocal fold slides were subjected to immunohistochemical reactions. Digital imaging software (ImageJ) was used to quantify the increase in brownish staining of the lamina propria structures of vocal folds, from superficial to deep layers.

RESULTS

There was an increase of collagen I and III immunoexpression in the elderly larynges, in both layers. Collagens IV and V were immunoexpressed in the vessels endothelium of the lamina propria and in the basement membrane. The immunoexpression of elastin decreased in the elderly larynges, in both lamina propria layers of the vocal folds.

CONCLUSION

A clear increase of collagens I and III and a decrease of elastic fibers were observed in the lamina propria of vocal folds. The concentration of collagens IV and V was the same across age groups. These findings suggest that as men age, the density of the extracellular matrix increases, brought about by an increase in collagen, while the loss of elastin results in decreased viscoelasticity.

Comparison of dysphonia severity index between younger and older carnatic classical singers and nonsingers

OBJECTIVES

The main objective of this study was to compare dysphonia severity index (DSI) and its parameters between Carnatic classical singers and nonsingers. The second objective was to investigate the effect of age on DSI and its parameters in both singers and nonsingers.

STUDY DESIGN

This study included 30 female Carnatic classical singers who were subdivided into two groups based on their age: 15 younger singers and 15 older singers. These 30 singers were compared with 30 age and gender matched nonsingers.

METHODS

From each participant, measures of highest phonational frequency, lowest intensity, jitter, and maximum phonation time were obtained. Using these, DSI values were calculated.

RESULTS

Singers had significantly greater highest phonational frequency, longer maximum phonation time, and higher DSI values. When compared with the younger participants, older participants had significantly reduced highest phonational frequency, maximum phonation time, and DSI values.

CONCLUSIONS

The results of this study suggest that DSI values vary between Carnatic classical singers and nonsingers, and hence separate normative data may need to be established for this group of singers for clinical comparison purposes.

Hyaluronic Acid Behavior in the Lamina Propria of the Larynx with Advancing Age

Objectives

To analyze the hyaluronic acid behavior in the lamina propria of the larynx with advancing age.

Study Design

Prospective study.

Setting

UNESP-Univ Estadual Paulista, Botucatu Medical School, Brazil.

Subjects and Methods

Thirty vocal folds were obtained at necropsy from 10 adult males (30–50 years old) and 20 geriatric males (10: 60–75 years old; 10: over 76 years old). Midmembranous vocal fold sections were subjected to immunohistochemical reactions. Digital imaging software (ImageJ) was used to quantify the hyaluronic acid distribution over the lamina propria of vocal folds, from superficial to deep layers.

Results

Hyaluronic acid distribution was homogeneous for the larynges, at both superficial and deep layers (41.6 and 38.5, respectively). For both 30- to 50-year-old men geriatric age groups, hyaluronic acid level was lower at both layers.

Conclusion

Hyaluronic acid level in the lamina propria of the larynx of geriatric men decreases with advancing age at both layers of the lamina.

Aging voice: presbyphonia

Presbyphonia is a physiological process of aging voice that includes morphological changes in the coverage mucosa, muscle, and cartilage. We revised the morphological, endoscopic, and vocal acoustic changes that occur in presbyphonia and discussed some treatments proposed to minimize glottal incompetence and improve vocal performance of the elderly.

The use of computed tomography in determining developmental changes, anomalies, and trauma of the thyroid cartilage

Recognition of injury to the hyoid bone and thyroid and cricoid cartilages is intrinsic to post-mortem examination. Due to its increasing brittleness with age the thyroid cartilage is particularly susceptible to injury following neck trauma, although there is inconsistency in the patterns of injury reported. In this study computed tomography scans of the head and neck of 431 deceased persons (235 males and 196 females) between the ages of 1 day and 100 years (mean age 35.93 ± 24.15), and including 25 victims of hangings, were examined to reveal the pattern of age-related change and the types of injury that occurred. Thyroid cartilage anomalies likely to cause confusion and be misinterpreted as trauma-related are documented. Angulation of the thyroid cartilage horns was found to change with age, and it is suggested this may be a significant factor in traumatic neck injury. Unlike in previous reports, the average age of hanging victims with fractures to the thyroid cartilage was 34 years. The base of the superior horn was the most common fracture site and in 50 % of hanging cases was associated with a ligature positioned on the thyrohyoid membrane or thyroid lamina. Although an age-related relationship exists it was not possible to establish narrow age-prediction ranges from calcification of the thyroid cartilage.

Challenges and opportunities in the management of the aging voice

Presbyphonia, or age-related dysphonia, is a diagnosis of exclusion, and other comorbidities must be considered in a complete evaluation of elderly patients with dysphonia. The aging voice can have a significant effect on the quality of life of the patient. In addition to the molecular effects of aging on the laryngeal tissues, the etiology of presbyphonia is often multifactorial because of comorbidities in the other organ systems involved in phonation. After a comprehensive evaluation, presbyphonia may be treated conservatively with voice therapy or with a range of interventions. Research into tissue engineering and electrical reanimation offers future options for treatment of presbyphonia. Currently, a multidisciplinary approach offers the most complete improvement in the vocal quality of life in this patient population.

[Functional anatomy of the larynx from clinical points of view: part II: Laryngeal mucous membrane, blood supply, innervation, lymphatic drainage, age-related changes]

Diseases of the larynx are of concern not only for ear, nose, and throat physicians and phoniatricians but also for other clinicians who treat the larynx either conservatively or surgically, including speech therapists, pediatricians, anesthetists, oncologists, pulmonologists, radiologists, and general practitioners. Based on today's state of knowledge and taking into account our own research results of the last years as well as clinical points of view, the present contribution gives a short overview of the anatomy and physiology of the larynx. Part 2 discusses the functional anatomy of the laryngeal mucous membrane (glycoconjugates, mucins, trefoil factor family peptides, antimicrobial substances, larynx-associated lymphoid tissue), the vascular supply, innervation, and lymphatic drainage, as well as age-related laryngeal changes and their effects on swallowing, breathing, and phonation.

Presbyphonia: a review

Recent research has led to greater understanding of the physiologic and cellular factors involved in the aging of laryngeal tissues, and concurrent advances in treatment promise improvements in clinical outcomes. This article reviews the current medical literature with respect to the age-related clinical and pathological changes in the larynx leading to presbyphonia.

Análise acústica da voz do idoso: caracterização da freqüência fundamental

OBJETIVO: estimar a freqüência fundamental (f0) de ambos os sexos na terceira idade e suas correlações perceptivo-auditivas (distinção de sexos e faixa etária). MÉTODOS: quatro indivíduos do sexo masculino e quatro do feminino, idades entre 60 e 76 anos, sem alteração de aparelho fonador, foram submetidos à gravação de leitura de texto (duas repetições). Os valores de f0 foram mensurados na vogal [a] em sílabas tônicas (T) e pré-tônicas (PT) do mesmo vocábulo (no início e no fim de sentenças) e submetidos à análise estatística. As amostras foram submetidas à análise perceptivo-auditiva (julgamentos de sexo e faixa etária) por 60 juízes. RESULTADOS: as médias de f0 em PT foram 114,14 Hz em início de sentença e 102,71 Hz em final no sexo masculino e 151 Hz em início e 146,87 Hz em final no sexo feminino. Para T, os valores foram 117,42 Hz em início de sentença e 92,85 Hz no sexo masculino em final e 175 Hz em início de sentença e 122,50 Hz no sexo feminino em final. Houve diferença significativa entre os sexos, bem como entre os falantes do mesmo sexo com relação à faixa etária adulta, especialmente para o feminino. Todos os falantes foram julgados corretamente quanto ao sexo, com faixa etária referida como inferior à real. CONCLUSÃO: houve diferença significante de medidas de f0 em idosos entre sexos masculino e feminino em relação à faixa etária adulta, tendo o último sexo apresentado declínio mais acentuado, sem interferências no julgamento de sexo e de faixa etária.

Influence of Age and Gender on the Dysphonia Severity Index

Attempts have been made to find objective parameters for assessing voice quality for many years. Objective measurements such as the dysphonia severity index (DSI), using four parameters (highest frequency, lowest intensity, maximum phonation time and jitter), appear to correlate well with perceptual evaluation. The aim of this study was to investigate the influence, if any, of age and gender on the DSI. The DSI of 118 non-smoking adults (69 females, 49 males, age range 20-79 years) without voice complaints was measured. Age has a significant effect on the DSI and on its parameters highest frequency and lowest intensity (only in females). Gender has no effect on the DSI, although it has a significant effect on the parameters highest frequency and maximum phonation time. To be able to distinguish between the effects of (normal) ageing and a voice disorder, normative data of a wide age range are essential. As a result of this study normative DSI values for gender and age have been made available.

Voice Handicap Index Results for Older Patients with Adductor Spasmodic Dysphonia

Adductor spasmodic dysphonia (ADSD) adversely affects a speaker's ability to effectively communicate. For many individuals suffering with ADSD, botulinum toxin (Botox) is the chosen treatment to remediate the symptoms. Although Botox's effects on symptom remediation have been examined before, patient perception of improvement post-Botox has been examined less frequently. Further, no studies have addressed the symptomatic changes in older adults that occur after Botox treatment. The Voice Handicap Index (VHI) was used as the instrument to assess older patient's (>65 years) perception of how ADSD impacts certain areas of their life pre- and post-Botox injection. The outcome of the VHI was related to a clinical judgment of voice severity. Participants also completed the Social Readjustment Rating Scale (SRRS) to examine overall stress level, and the outcome of the SRRS was correlated to postinjection VHI scores. Results indicated no significant correlation between VHI scores and voice severity or SRRS ratings. The current study suggests further study of voice outcomes with older adults with ADSD is needed.

Glottic Characteristics and Voice Complaint in the Elderly

This study evaluated the relationship between voice complaint and deviant vocal fold status with special regard to presbylarynx, in patients aged more than 60 years, with pharyngeal-laryngeal complaint. The material consisted of clinical histories and images obtained by laryngoscopies from protocols from the Larynx Institute-INLAR, Sao Paulo, Brazil, of 210 patients, 88 men and 122 women, aged more than 60 years, who had sought otorhinolaryngologic treatment. Indicative glottic characteristics of the presbylarynx, such as vocal fold bowing, prominence of vocal processes, and spindle-shaped glottic chink, were analyzed. The increase in mass, leukoplakia, and other vocal fold alterations, distinct from these two, grouped as miscellaneous, as well as the presence or absence of voice complaint were also analyzed. Vocal fold bowing, prominence of vocal processes, and spindle-shaped glottic chink showed a strong correlation among each other. The presence of presbylarynx was accompanied by less voice complaint than the presence of vocal fold mucosa alterations, which in turn are more common where an absence of presbylarynx exists.

Gender-specific distribution of glycosaminoglycans during cartilage mineralization of human thyroid cartilage

The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in the hypertrophic zone of growth plates, is not yet fully understood. Human thyroid cartilage can serve as a model to observe matrix changes associated with cartilage mineralization because the processes follow a distinct route, progress very slowly and show sexual differences. Histochemical staining for low sulphated GAG (chondroitin-4- and -6-sulphates) was decreased in the interterritorial matrix of thyroid cartilage starting at the beginning of the fifth decade, but not in the pericellular or territorial matrix of chondrocytes. Because cartilage mineralization progressed in the interterritorial matrix it seems likely that a decreasing content of chondroitin-4- and -6-sulphates is involved in the mineralization process. This hypothesis is supported by the observation that immunostaining for chondroitin-4- and -6-sulphates was weaker in mineralized cartilage areas than in unmineralized areas, whereas there was no difference in staining for keratan sulphate. In all life decades, female thyroid cartilages contained more chondrocytes with a territorial rim of chondroitin-4- and -6-sulphates probably preventing cartilage mineralization compared with age-matched male specimens. Taken together, the characteristic distribution pattern of chondroitin-4- and -6-sulphates being more concentrated in female than in male thyroid cartilages provided evidence that these macromolecules decrease in cartilage mineralization.

[Onco-surgical significance of anatomo-morphological specificity of glottic region of the larynx]

Glottis is a medium level of the larynx, involving the vocal cords, vocal process of arytenoid cartilage, and the anterior and posterior commissures. This region of heterogeneous histomorphological structure has specific characteristics: the internal striated muscles, the outer and inner perichondrium, atypical intra-cartilaginous areas of ossification, and unusual muscular insertion to cartilage. Microtomy of 3 thick successive sections was performed at the level of the upper surface of vocal cords. Standard histological staining methods were used. Microphotographs were taken by light microscope under different magnification along with histomorphometric measurements. Cancer spread is partially restricted by anatomic barriers: vocal ligament and tendon of the anterior commissure, and subsequently by the elastic cone. Easier tumor extension may be due to absence of the internal perichondrium and ossification of thyroid cartilage. Microvascularization of the anterior commissure is significant for tumor spread in glottis and paraglottic space. The role of commissural lymph network in local spread of the cancer is completely vague. It is certain that there are causes, still unrecognized, which have an effect on the pathways and direction of malignant tumor spread.