J. Anat. (1996) 188, pp. 173-182, with 9 figures Printed in Great Britain 173

The periepiglottic space: topographic relations and histological organisation

MARTINA MARIA REIDENBACH Institute of Anatomy, Rheinische Friedrich-Wilhelms-Universitat, Bonn, Germany

(Accepted 10 July 1995)

ABSTRACT Important aspects of histological organisation and topographic relations of the pre-epiglottic space are not fully understood. This region was therefore reinvestigated in plastinated serial sections of 19 human adult specimens. The cranial part of the pre-epiglottic space is homogenously filled with adipose tissue and extends around the epiglottis in a horseshoe fashion. Therefore, the term periepiglottic space (PES) is a more accurate description of this region. The cranial border of the PES is constituted by the hyoepiglottic membrane, which extends between the epiglottis and the tongue, and the hyoepiglottic ligament. The ligament consists of a cranial fibre layer anchored within the lingual muscles, and a caudal layer attached to the hyoid bone. Anterior to the lingual surface of the epiglottis, both fibre layers become apposed to form a dense collagenous mass, which may stabilise the epiglottis during deglutition. Contractions of the infrahyoid muscles will be transmitted to the thyrohyoid membrane anterior to the PES by numerous collagenous septa which originate from the membrane and radiate into the muscles. In contrast, the pre-epiglottic adipose tissue is not connected to the thyrohyoid membrane. The caudal part of the PES is subdivided by two paramedian sagittal collagenous septa. They include a medial compartment bordered by the epiglottis posteriorly and the thyroepiglottic ligament inferiorly. The two lateral subdivisions of the PES extend between the glands of the vestibular folds and towards the aryepiglottic folds, but a distinct confining collagenous layer is absent there. Posterolaterally, the PES is separated from the paraglottic space by the thyroarytenoid muscle and by a cranial extension of the fibrous sheet of the muscle. This collagenous tissue is often split into several layers and displays gaps which may facilitate the spread of malignancies.

Key words-: Human larynx; deglutition; laryngeal carcinoma.

epiglottic space is described as continuing into the INTRODUCTION adjacent laryngeal tissues. The hyoepiglottic mem- The term 'pre-epiglottic space' is not mentioned in the brane is also not mentioned in the Nomina Anatomica Nomina Anatomica (International Anatomical No- (International Anatomical Nomenclature Committee, menclature Committee, 1983, 1989), but it is defined 1983, 1989). According to recent investigations in the anatomical literature. According to Pernkopf (Vandaele et al. 1995), it is part of the submucosal (1952), Lanz & Wachsmuth (1955) and Zenker (1958), fascial tissue of the laryngopharynx and covers the the pre-epiglottic space has the following boundaries hyoepiglottic ligament cranially. This ligament (Fig. 1 a): anteriorly, the thyrohyoid membrane with connects the lingual surface of the epiglottis and the the thyrohyoid ligaments, and the cranial part of the hyoid bone (Williams et al. 1989). thyroid cartilage; superiorly, the hyoepiglottic mem- The pre-epiglottic space contains adipose tissue brane and the hyoepiglottic ligament; posteriorly, the (Pernkopf, 1952; Lanz & Wachsmuth, 1955; Anson & lingual surface of the epiglottis; inferiorly, the McVay, 1971; Williams et al. 1989), the 'corpus attachment of the epiglottis to the thyroid cartilage by adiposum pre-epiglotticum' of the Nomina the thyroepiglottic ligament. Laterally, the pre- Anatomica (International Anatomical Nomenclature

Correspondence to Dr Martina Maria Reidenbach, Institute of Anatomy, Rheinische Friedrich-Wilhelms-Universitat, Nussallee 10, 53115 Bonn, Germany. 174 M. M. Reidenbach

~ ~~~~W.w. ..1W : -4r -1? Fig. 1. Schematic drawing ofmedian sagittal section oflarynx, viewed medially. (a) Topography ofthe pre-epiglottic space and its boundaries according to the literature. Asterisk, pre-epiglottic space, containing pre-epiglottic fat pad; arrow, hyoepiglottic membrane; 1, median hyoepiglottic ligament; 2, median thyrohyoid ligament; 3, thyroepiglottic ligament; 4, root of tongue; 5, epiglottis; 6, thyroid cartilage; 7, cricoid lamina; 8, cricoid arch; 9, hyoid bone; 10, transverse arytenoid muscle; 11, laryngeal ventricle. (b) Planes of horizontal (cf. Figs 3-7) and frontal (cf. Fig. 8) sections.

Committee, 1989; not included in the earlier 1983 According to Sato et al. (1993), the posteroinferiot edition). During deglutition, this fat pad is deformed boundary is constituted by the thyroglottic ligament. and pressed against the epiglottis, causing it to descend This ligament was observed in a fetal larynx of 24 wk and partly close and protect the entrance of the larynx by Tucker & Smith (1962), who introduced the term (Passavant, 1886; Fink, 1975, 1976; Fink et al. 1979). 'thyroglottic ligamdnt'. The authors applied it to a From a clinical standpoint, the pre-epiglottic space is collagenous layer fanning out between the anterior ofgreat interest, particularly with regard to the spread part of the vocal cord and the thyroid cartilage. of laryngeal carcinoma. Tumours arising cranial to Concerning the posterior boundary of the pre- the glottis frequently invade the pre-epiglottic space epiglottic space, Clerf (1944) pointed out that it is (Clerf, 1944; Bocca et al. 1968; Olofsson & van constituted by an elastic membrane, in addition to the Nostrand, 1973; Micheau et al. 1976; Kirchner, 1977; narrow lower part of the epiglottis. However, the Million, 1993). In the literature, there is no agreement author did not provide further information on this as to whether the pre-epiglottic space is subdivided by membrane. collagenous septa which may represent anatomical Altogether, important aspects of histological or- barriers against tumour growth. Some authors have ganisation and topographic relations of the pre- described a collagenous layer completely dividing the epiglottic space are still a matter of controversy. This pre-epiglottic space along the median sagittal plane physiologically and clinically interesting anatomical (Testut & Jacob, 1914; Testut, 1930; Guerrier & region has therefore been reinvestigated in the present Andrea, 1973). This septum is not mentioned else- study. The study is based on the examination ofwhole where (Pernkopf, 1952; Lanz & Wachsmuth, 1955; organ sections of human adult larynges and the Braus & Elze, 1956; Anson & McVay, 1971; Maguire adjacent pre-epiglottic regions. For tissue preparation, & Dayal, 1974; Williams et al. 1989). Dayal et al. the technique of plastination was applied, which is (1972) described a condensation of fibroelastic tissue advantageous for the examination both of the healthy in the midline of the pre-epiglottic space, but denied (Eckel et al. 1993) and diseased (Eckel, 1993) larynx. the existence of a sharply defined septum. It is not fully understood which anatomical structures border the pre-epiglottic space inferiorly and posteriorly. Periepiglottic space 175

MATERIALS AND METHODS RESULTS Terminology The anatomical structures which border the PES Maguire & Dayal (1974) found the pre-epiglottic cranially and ventrally can be defined easily. In space to extend around the epiglottis in a horseshoe contrast, the topographic relations of its posterior, fashion. They therefore suggested the term 'peri- inferior and lateral extensions are much more com- epiglottic space', which is more accurate and has been plicated. They depend on the level of investigation, as adopted in this work, abbreviated to PES. does the histological organisation of the contents of The material was taken from 19 human cadavers (9 the PES. males, 10 females) aged between 44 and 87 y (mean 65.8 y). The cause of death was unrelated to upper Cranial border of the PES airways or digestive tract disease or injury. The larynges with the PES and the thyrohyoid membrane, Cranially, the PES is bordered by several layers of the hyoid bone and the root of the tongue were collagen fibres, which are loosely apposed and extend removed en bloc. The specimens were fixed by in an anteroposterior direction (Fig. 2a). The cranial immersion in a 10% formaldehyde solution for at fibres radiate into the muscle tissue at the root of the least 3 months and were then subjected to a tongue, whereas the caudal fibre group is attached to plastination process (Fritsch, 1988, 1989a; Schmolke, the periosteum of the upper rim of the hyoid bone. A 1994). After rinsing in water for 48 h to remove the few of the cranial fibres course beneath the mucosal formaldehyde, the specimens were dehydrated in lining of the epiglottic valleculae and join the 100% acetone at -25 °C (Schwab & Hagens, 1981) perichondrium anterior to the free part of the changed weekly for 4 wk. This was followed by epiglottis. These fibres constitute the weak another 2 wk in 100 % acetone at room temperature hyoepiglottic membrane. The remaining collagen to dissolve the fat. Impregnation was then performed fibres of both the cranial and caudal layers interlace in a vacuum chamber (Hagens, 1985) with a mixture into the dense fibrous mass of the median of the epoxy resins Biodur E12 (2 parts) and Biodur hyoepiglottic ligament (Fig. 2a). This extends E6 (1 part), and the accelerator Biodur E600 caudalward at the lingual surface of the epiglottis and (0.2 vol %) over 2 wk. After another 2 wk of poly- contains numerous groups of glands. A few merisation at 50 °C, the epoxy blocks were cut collagenous fibres of the median hyoepiglottic liga- serially with a diamond wire saw (Well, W. Ebner, ment curve cranially and radiate into the perichon- Mannheim, Germany) into 500, 600, 700, or 800 gm drium of the free part of the epiglottis. In most sections (Br6kelmann & Prondzinsky, 1985) in sagittal, specimens, a small amount of collagenous tissue horizontal or frontal planes. The cutting diamond extends between the perichondrium of the lateral wire had a diameter of 220 gm and caused only slight margins of the epiglottis and the greater cornua of the tissue loss between sections. Each section was hyoid bone on either side. mounted on a glass slide with a mixture of Biodur E12 (10 parts), Biodur El (3 parts), and benzylbenzoate (4 Anterior border of the PES parts) (Fritsch, 1988). This mixture polymerised over 24-48 h at 50 'C. Afterwards, the sections were firmly The thyrohyoid membrane connects the hyoid bone attached to the glass slides and were smoothed with a and the upper rim of the thyroid cartilage. The grinding machine (Fritsch & Hegemann, 1991) and median thyrohyoid ligament is thicker than the lateral then polished manually to total transparency. The parts of the membrane, but appears rather weak sections were stained with azure II/methylene blue compared with the dense fibrous mass of the median and basic fuchsin (Laczko & Levai, 1975) at 90 'C for hyoepiglottic ligament (Fig. 2a). The lateral parts of several minutes until the desired intensity was the thyrohyoid membrane are attached to the inferior obtained (Fritsch, 1989b). With this staining, cartilage borders of the greater cornua of the hyoid bone. The appears violet, bony tissue brownish-yellow, and median thyrohyoid ligament is anchored at the upper collagen blue-violet. Fat is not stained and appears rim of the body of the hyoid bone. There, the transparent. Due to the natural colour of myoglobin, collagenous fibres forming the ligament originate muscle fibres are light brown. Blood vessels and bone together with the caudal fibre layer of the median marrow containing red blood cells are marked by the hyoepiglottic ligament (Fig. 2a). The same area of the brownish coloured haemoglobin within the erythro- hyoid periosteum gives rise to a few inconspicuous cytes. collagenous fibres which radiate into the pre-epiglottic 176 M. M. Reidenbach

2a -7:, Fig. 2. Paramedian sagittal section of larynx. (a) Plastinated female larynx, aged 73 y, 800 gm, x 3. T, tongue; H, hyoid bone; E, epiglottis; TC, thyroid cartilage; A, arytenoid cartilage; C, cricoid lamina; TM, thyroarytenoid muscle; TA, transverse arytenoid muscle; P, posterior cricoarytenoid muscle; L, lymphoid nodule; x, cartilaginous spine at the lateral rims of the thyroid notch. Cranially, the PES (asterisk) is bordered by the hyoepiglottic membrane (long arrow) and the dense median hyoepiglottic ligament (short arrow). The caudal fibre layer of the median hyoepiglottic ligament originates at the same area of the periosteum ofthe upper rim of the hyoid bone as the thyrohyoid ligament (arrowheads). The thyrohyoid ligament appears rather weak compared with the hyoepiglottic ligament. (b) Plane of section, indicated on schematic drawing of a horizontal section of the larynx at the level of the glottis. 1, thyroid cartilage; 2, arytenoid cartilage; 3, cricoid arch; 4, thyroarytenoid muscle with medial and lateral portions; 5, posterior cricoarytenoid muscle; 6, glottis; 7, pharynx; 8, inferior pharyngeal constrictor muscle; arrowhead, vocal ligament; arrow, articular cleft of cricoarytenoid joint. fat pad. Numerous connective tissue septa subdividing Posterior border of the PES the infrahyoid muscles are attached to the thyrohyoid membrane (Fig. 4). Only a few collagenous fibres At the level of the hyoid bone, the PES extends originate from the membrane to radiate into the pre- dorsalward beyond the lateral margins ofthe epiglottis epiglottic fat pad. Caudally, the thyrohyoid mem- into the aryepiglottic folds beneath the mucosal lining brane is attached to the perichondrium at the anterior (Fig. 3 a). Caudalward, the aryepiglottic folds contain surface of the upper rim of the thyroid cartilage. increasing amounts of irregularly arranged collagen and muscle fibres and groups of glands. The region of Caudal border of the PES the folds can be distinguished from the dorsolateral extensions of the pre-epiglottic fat pad because of its The thyroepiglottic ligament consists of several par- different histological appearance, though a distinct allel collagenous strata, which are arranged sagittally anatomical border, i.e. a collagenous septum, is absent and separated by layers of adipose tissue (Fig. 6). (Fig. 5a). Ventrally, the collagenous fibres radiate into two cartilaginous spines which extend dorsalward from Lateral borders of the PES and histological the lateral rims of the thyroid notch (Figs 2 a, 6). Near its contents the airway lumen, the thyroepiglottic ligament organisation of includes groups of glands. The lateral collagenous Cranially, the greater cornua of the hyoid bone layers of the ligament are continuous with the constitute the lateral borders ofthe PES (Fig. 3 a). The quadrangular membrane dorsally (Fig. 6a) and adipose tissue is lobulated by collagen fibres with a converge towards the median sagittal plane caudally wavy arrangement and contains conspicuous blood (Fig. 8a). vessels, especially near the midline (Fig. 3 b). More Periepiglottic space 177

Fig. 3. Horizontal section of male larynx at the level of the hyoid bone (cf. Fig. 1 b), aged 52 y, 600 Pm. Same specimen as in Figures 4-6. H, hyoid bone; E, epiglottis; F, pre-epiglottic fat pad. (a) The pre-epiglottic fat pad continues beyond the lateral margins of the epiglottis into the aryepiglottic folds (asterisks). The median thyrohyoid ligament (arrowhead) is separated from the hyoid bone by adipose tissue. In order not to disturb the impression of the histological appearance, the lateral borders of the medial region shown at higher magnification in (b) are indicated by arrows pointing from the airway lumen. x 2.8. (b) The adipose tissue of the PES is lobulated by wavy collagenous septa (partly marked by arrows) and contains conspicuous blood vessels (black, partly marked by arrowheads). x 8. Fig. 4. Horizontal section of male larynx, caudal to the hyoid bone (cf. Fig. 1 b), aged 52 y, 600 lim. E, epiglottis; IM, infrahyoid muscles; F, pre-epiglottic fat pad. (a) At the right lateral margin ofthe epiglottis, collagenous fibres are apposed to form an incomplete sagittal septum (arrow). x 2.8. Enclosed area is shown at higher magnification in (b). (b) Numerous collagenous septa (arrowheads) take their origin from the thyrohyoid membrane (arrow) and radiate into the infrahyoid muscles. x 5. caudally, the fat pad is subdivided into a medial and they are attached to the rims of the thyroid notch and two lateral regions by two sagittal collagenous fibre caudalward are continuous with the lateral septa (Figs 5, 9). They originate from the connective collagenous layers of the thyroepiglottic ligament tissue surrounding groups of glands at the lateral (Fig. 8 a). Both connective tissue septa form the lateral margins of the epiglottic cartilage. Dorsally, the septa boundaries of an actual pre-epiglottic space, bordered join the quadrangular membrane (Fig. 5 a). Ventrally, by the epiglottis dorsally. It contains adipose tissue 178 M. M. Reidenbach

Fig. 5. Horizontal section of male larynx at the level of the upper rim of the thyroid cartilage (cf. Fig. 1 b), aged 52 y, 600 gm. T, thyroid cartilage; E, epiglottis; IM, infrahyoid muscles; G, groups of glands of the aryepiglottic folds. (a) The pre-epiglottic fat pad is subdivided into a median, actual pre-epiglottic region (cf. b), and 2 lateral regions by 2 collagenous fibre septa (arrows). The lateral regions of the PES extend dorsalward towards the aryepiglottic folds. Posterolaterally, a thin collagenous layer (arrowheads) constitutes the medial border of a triangular space of areolar tissue adjacent to the thyroid cartilage. Asterisk, thyroid notch. x 2.7. (b) Median, actual pre-epiglottic region of PES at higher magnification. In contrast to the lateral extensions of the PES (asterisks), the median region contains numerous collagenous fibres (partly marked by arrows) and blood vessels (black, partly marked by arrowheads). x 5.5. Fig. 6 Horizontal section of male larynx at the level of the thyroepiglottic ligament (cf. Fig. 1 b), aged 52 y, 600 gim. T, thyroid cartilage; A, arytenoid cartilage; TM, craniolateral fibres of the thyroarytenoid muscle; G, groups of glands; L, thyroepiglottic ligament. (a) The lateral fibre layers of the thyroepiglottic ligament continue dorsalward into the quadrangular membrane (arrowheads). Caudal extensions of the pre-epiglottic fat pad (asterisks) are located between the thyroepiglottic ligament and the thyroid cartilage. x 2.7. (b) Thyroepiglottic ligament at higher magnification. The ligament consists of several strata of sagittally oriented collagenous layers (arrows) separated by adipose tissue and groups of glands. The collagenous fibres radiate into 2 cartilaginous spines (x) at the rims of the thyroid notch. x 5.5. and numerous collagen fibres, conspicuous blood on both sides. It is immediately adjacent to the thyroid vessels and groups of glands (Fig. 5). Lateral to this perichondrium anterolaterally. Posterolaterally, it is pre-epiglottic space, a region of slightly lobulated bordered by a thin collagenous layer which is adipose tissue extends towards the thyroid cartilage continuous with the fibrous sheet of the thyro- Periepiglottic space 179

epiglottis not only form the weak hyoepiglottic membrane but, from the present results, the caudal fibres constitute the cranial fibre layer of the strong median hyoepiglottic ligament. Zenker (1958) de- scribed the hyoepiglottic ligament as being anchored to the hyoid bone ventrally. The present observations show that these fibres represent only the caudal layer of the median hyoepiglottic ligament, which connects the lingual surface ofthe epiglottis both to the muscles of the tongue and the hyoid bone. The median hyoepiglottic ligament forms a dense fibrous layer at the lingual surface ofthe epiglottis. This reinforcement of the cartilaginous tissue may facilitate the mech-

7 ..%-.a { anism of epiglottic downfolding during deglutition. Fig. 7. Horizontal section of female larynx at the level of the Fink et al. (1979) proposed a conical deformation of vestibular folds (cf. Fig. 1 b), aged 87 y, 800 gm. T, thyroid the epiglottis around the medial region of its lower cartilage; A, arytenoid cartilage; TM, cranial fibres of thyro- part. The position of this area of the cartilage is arytenoid muscle; TA, transverse arytenoid muscle; G, groups of stabilised by the median hyoepiglottic ligament. This glands; P, piriform sinus. Arrows point towards triangular space of areolar tissue bordered by the thyroid cartilage laterally and the was confirmed by the results of scanning electron thyroarytenoid muscle medially. Arrowheads, blood vessels. The microscope investigations by Vandaele et al. (1995), ventricular folds contain groups of glands medially, and the cranial who found a vertical orientation of the collagen fibres fibres of the thyroarytenoid muscle laterally (right side). Occasionally, this histological organisation is disturbed by caudal in the medial region of the epiglottis and concluded extensions of the pre-epiglottic adipose tissue (left side, asterisk). that there is an increased resistance against defor- x 3. mation along the long axis of the cartilage. In addition, Vandaele et al. (1995) described a lateral hyoepiglottic ligament bridging between the lateral arytenoid muscle (Fig. 8) and is attached to the margins of the epiglottis and the greater cornua of the perichondrium of the thyroid cartilage in some cases. hyoid bone on each side. According to the present More often, this fibrous tissue splits into several results, this is a rather weak anatomical structure and incomplete layers (Fig. 8b), which radiate into the was not prominent in all specimens investigated. pre-epiglottic fat pad cranially. The fibrous sheet of the thyroarytenoid muscle constitutes the medial boundary of a triangular space extending to the thyroid cartilage laterally and the mucosal lining of Anterior border the piriform sinus dorsally (Fig. 7). This region Contractions of the infrahyoid muscles will be contains areolar tissue and groups of blood vessels transmitted to the thyrohyoid membrane and the and nerves. At the level of the thyroepiglottic thyrohyoid ligament by the connecting collagen septa. ligament, the caudal parts of the pre-epiglottic fat pad Probably, these passive movements of the membrane are located between the ligament medially and the will have little effect on the pre-epiglottic adipose thyroid cartilage laterally (Fig. 6). At a more caudal tissue, because both structures are not firmly attached level, the vestibular folds are composed of masses of to each other. Thus contractions of the infrahyoid glands medially and the fibres of the thyroarytenoid muscles alone cannot bring about an effective de- muscle laterally. Occasionally, irregular caudal formation of the pre-epiglottic fat pad and will not extensions of the pre-epiglottic adipose tissue are contribute to the closing mechanism of the larynx included (Figs 7, 9). during swallowing. This confirms the original view of Passavant (1886). He stressed the importance of the dorsalward displacement of the root of the tongue for DISCUSSION the compression of the pre-epiglottic fat pad which would then the downwards. Cranial border push epiglottis Recently Vandaele et al. (1995) demonstrated by radiographic In contrast to the results of Vandaele et al. (1995), the methods that especially the first movement of the collagen fibres extending between the muscle tissue at epiglottis during deglutition is caused by a bulging of the root of the tongue and the lingual surface of the the tongue in a posterior direction. 180 M. M. Reidenbach

M 4-

Fig. 9. Topography and extensions of the pre-epiglottic adipose tissue. Schematic drawing of frontal section of larynx, viewed dorsally. Left side: Topography. 1, epiglottis; 2, hyoid bone; 3, hyoepiglottic membrane; 4, thyroid cartilage; 5, thyrohyoid mem- brane; 6, cricoid cartilage; 7, cricothyroid muscle; 8, lateral cricoarytenoid muscle; 9, thyroarytenoid muscle; 10, vestibular folds with groups of glands; arrowheads, conus elasticus with vocal ligament (small arrowhead); arrow, cranial extension of the fibrous sheet of the thyroarytenoid muscle, attached to thyroid peri- chondrium. Right side: Extensions of the PES (black). The cranial part of the PES extends beyond the lateral margins of the epiglottis (white-bordered arrow). The caudal part of the PES is subdivided in a median and 2 lateral from the sections of female larynx (cf. Fig. 1 b), 63 y, 600 (M) (L) regions, separated Fig. 8. Frontal gm. the muscle and its fibrous T, thyroid cartilage; E, epiglottis; VM, vocalis muscle (medial paraglottic space (x) by thyroarytenoid case fibrous sheet is not attached to the of and sheet. In this thyroid portion of thyroarytenoid muscle); G, groups glands the cranial of the PES is continuous with the collagenous fibre masses of thyroepiglottic ligament; VF, vestibular cartilage, part paraglottic space (arrowhead). The medial region of the PES has a folds; TM, lateral part of thyroarytenoid muscle; F, pre-epiglottic definite caudal the In fat (a) The collagenous septa (long arrows) subdividing border, thyroepiglottic ligament (line M). pad. sagittal the caudal border of the lateral cannot be the PES into a median and 2 lateral regions continue into the lateral contrast, region clearly defined The extends caudalward fibre of the ligament (short arrows). The (area L). paraglottic space beyond layers thyroepiglottic the level of the thyroepiglottic ligament has no distinct cranial border. Lateral glottis (arrow X). extensions of the pre-epiglottic fat pad bulging towards the vestibular folds are separated from another layer of adipose tissue periepiglottic space as homogenously filled by adipose adjacent to the thyroid cartilage by a conspicuous fibrous sheet (arrowheads); it is connected with the fibrous sheet of the tissue. According to the present results, this is true thyroarytenoid muscle. x 2.6. (b) The lateral extensions of the pre- only for the cranial parts of the space (Fig. 9). More epiglottic fat pad extend caudalward beyond the epiglottis. The caudally, it is subdivided into a median and two fibrous sheet bordering the adipose tissue layer adjacent to the The absence of a distinct dorsal and thyroid cartilage is well defined on the left side (arrowheads) but lateral regions. split into several layers on the right (arrows). x 2.2. caudal anatomical border confining the lateral extensions is of clinical importance, especially with to the of carcinoma. It is Inferior, posterior and lateral histological regard spread laryngeal borders; doubt that carcinoma in the organisation of the contents of the PES beyond laryngeal arising supraglottic region usually remains confined to it The pre-epiglottic space as defined in the literature (Bocca et al. 1968; Kirchner, 1969, 1977, 1984; (see Introduction) is not actually located pre- Micheau et al. 1976; Kirchner & Carter, 1987; epiglottically, anterior to the epiglottis, but extends Million, 1993; Wong & Wang, 1995). But according dorsolaterally beyond the lateral margins of the to the present results, especially tumours of the lateral epiglottis. Thus the concept of the periepiglottic space regions of the PES, may extend caudalward and cross advanced by Maguire & Dayal (1974) is confirmed as the laryngeal ventricle to involve both the false and being more accurate. These authors described the true vocal cords. This growth pattern is described as Periepiglottic space 181 transglottic carcinoma (Kirchner, 1969, 1984; Silver, DAYAL VS, BAHRI H, STONE PC (1972) Pre-epiglottic space. 1981; Biller & Lawson, 1984; Mittal et al. 1984; Archives of Otolaryngology 95, 130-133. ECKEL HE (1993) Topographische und klinisch-onkologische Beitler et al. 1994), which is characterised by a high Analyse lokoregionarer Rezidive nach transoraler Laserchirurgie incidence of cervical metastasis (Hao et al. 1995). zur Behandlung von Kehlkopfcarcinomen. Laryngo-Rhino- Former investigators reported transglottic carcinoma Otologie 72, 406-411. ECKEL HE, SITrEL CH, SPRINZL G, WALGER M, KOEBKE J (1993) as spreading within the paraglottic space (Kirchner et Plastination: a new approach to morphological research and al. 1974; Biller & Lawson, 1991; Mittal et al. 1984; instruction with excised larynges. Annals of Otology, Rhinology Beitler et al. 1994). As was mentioned in the and Laryngology 102, 660-665. Introduction, the paraglottic space is not mentioned FINK BR (1975) The Human Larynx. A Functional Study, pp. 31-166. New York: Raven Press. in the Nomina Anatomica (International Anatomical FINK BR (1976) The median thyrohyoid fold: a nomenclatural Nomenclature Committee 1983, 1989). It was defined suggestion. Journal of Anatomy 122, 697-699. by Tucker & Smith (1962) and Tucker (1963) as the FINK BR, MARnN RW, RoHRMANN CA (1979) Biomechanics of the human epiglottis. Acta Otolaryngologica 87, 554-559. region bounded by the thyroid cartilage antero- FRITSCH H (1988) Developmental changes in the rectorectal region laterally, the conus elasticus inferomedially, the of the human fetus. Anatomy and Embryology 177, 513-522. laryngeal ventricle and the quadrangular membrane FRITSCH H (1989a) Topography of the pelvic autonomic nerves in medially, and the mucosal lining of the piriform sinus human fetuses between 21-29 weeks of gestation. Anatomy and Embryology 180, 57-64. dorsally. According to this definition, the paraglottic FIUTSCH H (1989b) Staining of different tissues in thick epoxy space includes the thyroarytenoid muscle and the resin-impregnated sections of human fetuses. Stain Technology small triangular region of adipose tissue located 64, 75-79. FRITSCH H, HEGEMANN L (1991) Vereinfachung der Herstellung between the thyroid cartilage laterally, the thyro- plastinationshistologischer Praparate durch Einsatz einer arytenoid muscle medially, and the piriform sinus Schleifmaschine. Anatomischer Anzeiger 173, 161-165. dorsally. Maguire & Dayal (1974) and recently Sato et GUERRIER Y, ANDREA M (1973) Les loges preepiglottiques. Nuovo al. (1993) suggested that the term 'paraglottic space' Archivio Italiano di Otologia, Rinologia e Laringologia 1, 3-21. HAGENS G voN (1985) Heidelberger Plastinationshefter, pp. 1-9. should be confined to the triangular region included Anatomisches Institut I, D-69120 Heidelberg, Germany. between the thyroid cartilage laterally and the HAO SP, MYERS EN, JOHNSON JT (1995) T3 glottic carcinoma thyroarytenoid muscle medially, and to exclude the revisited. Archives ofOtolaryngology, HeadandNeck Surgery 121, 166-170. region of the muscle. The present results confirm this INTERNATIONAL ANATOMICAL NOMENCLATURE COMMITTEE (1983) concept. The region of the thyroarytenoid muscle is Nomina Anatomica, 5th edn, pp. A38-39. Baltimore: Williams & clearly separated both from the extensions of the pre- Wilkins. epiglottic adipose tissue and the areolar tissue adjacent INTERNATIONAL ANATOMICAL NOMENCLATURE COMMITTEE (1989) Nomina Anatomica, 6th edn, pp. A43-44. Edinburgh: Churchill to the thyroid cartilage. However, it is important to Livingstone. stress that both the periepiglottic and the paraglottic KIRCHNER JA (1969) One hundred laryngeal cancers studied by space do not represent closed compartments, because serial section. Anials ofOtology, Rhinology and Laryngology 78, they are not surrounded definite ana- 689-709. entirely by KIRCHNER JA (1977) Two hundred laryngeal cancers: patterns of tomical boundaries, and are partly continuous with growth and spread as seen in serial sections. 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