ANALYSIS OF MEASUREMENTS AND PROPORTION OF LARYNX OF YOUNG AND ADULT INDIVIDUALS OF DOMESTIC CATTLE

Jarosław Wysocki¹, Ewa Kielska¹, Anna Charuta¹, Izabela Janiuk¹, Jerzy Reymond^2
1 Vertebrates Morphology Department of University of Humanities and Sciences in Siedlce, Poland
² Department of Maxillofacial Surgery, Regional Hospital of Radom, Poland

ABSTRACT

The studies were conducted on 27 bovine larynges (13 young and 14 adult ones). After staining in 10% formaldehyde solution, anatomical dissection using standard set of surgical equipment was performed. Morphological observations as well as numerical, angular and surface measurements were made. The measurements were made using Multiscan, a system of a computer analysis of  pictures. Several basic size parameters and several indicators, calculated on the base of them have been considered. The results were analyzed statistically using t-Student test at the significance level α=0,05.

Statistically significant differences between genders of the studied specimens were stated, as well as in young and in adult ones and almost all of size parameters were greater in male than in female specimens. Among basic size parameters in young animals there were: the thyroid cartilage angle and the size of intercartilaginous part of true glottis. In adult ones there were: the span of the anterior as well as posterior horns of the thyroid cartilage, the superior horn length, the thyroid cartilage length and the arytenoid cartilage width. The influence of age was important in almost all basic size parameters. The analysis of relative parameters (indicators) showed that proportions of the larynx, as well as minor and the adult animals, are determined by sex, not by age.

Conclusion of the research is that a certain sexual dimorphism in cattle larynx is present. It is clearly visible just in young animals, however it transforms during maturation process which could be named “the mutation”, as it is described in humans.

Key words: larynx, cattle, anatomy, measurements, minor, adult.

INTRODUCTION

Anatomy of the animal larynx, however thoroughly described in textbooks [1,4], is not sufficiently studied as far as their dimensions, proportions and postnatal development are concerned. In opposite a whole range of measuring data characterizing human larynx was gathered in the last few years [6,13]. A range of work from functional and clinical larynx anatomy is carried out also on animals, however without previous thorough anatomical study, especially measurements [3,5,13]. In order to fill this gap some authors undertook their researches [7,8,11,14], however there are no studies available in literature concerning larynx anatomy during animal development period. Acquaintance of these changes would facilitate interpretation of some results of experimental research founded on modelling of larynx action and would be valuable for those planning research experiments with utilization of animal models.

MATERIAL AND METHODS

The research was conducted on 27 cattle larynges (13 minors and 14 adults). The division of the cattle into minors and adults was done according to textbook data concerning the start of adolescence at 6-9 months of life [1]. Calves and heifers were from12 to16 weeks old, cows and bulls were old breeding animals.

Larynges used for the study were taken from a slaughterhouse where cattle were routinely slaughtered. Therefore, the approval of Bioethical Commission was not needed.

After collecting the larynges were fixed in a 10% solution of formaldehyde for 6 weeks, then they were prepared using a standard set of microsurgical instruments. Methods of work were to do morphological observations and execution of a range of linear, angular and surface measurements. In anatomical description the official anatomical terms cited in suitable textbooks have been considered [10, 12]. The measurements were performed using computer system of image analysis MULTISCAN.

In order to achieve objective values of the measurements, an arithmetic average was calculated () marking the minimum and the maximum parameters of the studied larynges as well as the standard deviation (SD). The results were analysed statistically using t-Student test with α =0.05. The averages differed significantly when│t_emp│>t _α,υ; t _{0.05, 11}= 2.201.

The studied basic parameters have been shown below on Figs. 1-4.

Fig. 1. The thyroid cartilage measurement scheme

Fig. 2. The cricoid cartilage measurement scheme

Fig. 3. The arytenoid cartilage measurement scheme (left side) and the epiglottic cartilage measurement scheme (right side)

Fig. 4. Whole larynx measurement scheme

They were:

1. The thyroid cartilage

1. craniocaudal dimension of the plate in a medial line

2. distance between overhead / front corners

3. distance between back corners

4. width at the level of laryngeal prominence (if there is no maximum width)

5. maximum height of the plate

6. length of the front corner

7. length of the back corner

8. maximum craniocaudal dimension

9. angle between the plates

2. The cricoid cartilage

1. width of the cricoid cartilage at the central point of the cricoarytenoid joint capsule

2. craniocaudal dimension of the arch in a medial line

3. craniocaudal dimension of the plate in a medial line

4. external fibular dimension measured at the edge of caudal cartilage

5. surface of the internal contour (lumen) of the cricoid cartilage

6. distance between the central point of the cricothyroid joint capsule and the ventral pole of the cricoid cartilage in a medial line

7. the angle created by the above line with the fibular plane

8. distance between the central point of the cricoarytenoid joint capsule and the ventral pole of the cricoid cartilage in a medial line

9. the angle created by the above line with the fibular plane

3. The arytenoid cartilage

1. total height measured from the base to the top

2. distance between the top of the vocal process and the cente of the cricoid capsule

3. distance between the top of the muscular process and the cente of the cricoid capsule

4. The epiglottic cartilage

1. maximum height

2. maximum width

5. Whole larynx dimensions

1. craniocaudal dimension of the whole larynx (from the top of the epiglottic cartilage to the lower edge of the cricoid cartilage)

2. length of the membranous part of the true glottis

3. length of the intercartilaginous part of the true glottis

Table 1. Indicators characterising individual proportions of larynx structures

successive parameter	way of calculating	description
		The thyroid cartilage
1	1f/1h	height of the top corner to total height of the thyroid cartilage
2	1g/1h	height of the bottom corner to total height of the thyroid cartilage
3	1h/1d	height of the thyroid cartilage to its width
4	1h/5a	height of the thyroid cartilage to the height of the whole larynx
5	1b/1c	Top corners span to bottom corners span of the thyroid cartilage
		The cricoid cartilage
6	2c/2d	Height of the plate to fibular dimension of the cricoid cartilage
7	2b/2d	Height of the arch to fibular dimension of the cricoid cartilage
8	2f/2d	Distance of the surface of the cricoid joint from the arch to fibular dimension of the cricoid cartilage
9	2h/2d	Distance of the surface of the arytenoid joint from the arch to fibular dimension of the cricoid cartilage
10	2c/5a	Height of the plate to height of the whole larynx
11	2a/2d	Width of the cricoid cartilage to its fibular dimension
		The arytenoid cartilage
12	3b/3a	Length of the vocal process to height of the arytenoid cartilage
13	3c/3a	Length of the muscle process to height of the arytenoid cartilage
14	3a/5a	Height of the the arytenoid cartilage to height of the whole larynx
		The arytenoid cartilage
15	4a/4b	Height of the the arytenoid cartilage to its width
16	4a/5a	Height of the the arytenoid cartilage to height of the whole larynx
		True glottis
17	5b/5c	The relation of the membranous part of the true glottis to the intercartilaginous part of the true glottis

On the base of initial size parameters convenient indicators were calculated larynges referring to age and sex. The list of indicators is shown in Table 1.

RESULTS

Cattle larynges are characterised by considerable width (Fig. 5, 6, 7) resulting both from the shape of the thyroid cartilage (cartilago thyroidea) and the cricoid cartilage (cartilago cricoidea). The thyroid cartilage is quite wide and low. Front and back corners (cornu anterius et posterius) are well-shaped. The back corner is hood curved to the centre. The result is that the distance between the front corners is similar to the one between the back corners. The thyroid fissure (incisura thyroidea anterior) does not exist. The back thyroid fissure (incisura thyroidea posterior) is shallow. In its area there is a clear, wide and low laryngeal prominence (prominentia laryngea). The thyroid cartilage plates (laminae cartilaginis thyroideae) make a clear angle close to 90°. The cricoid cartilage is seal ring-shaped (Fig. 8) with a low plate (lamina cartilaginis cricoideae) and considerably high arch (arcus cartilaginis cricoideae). The arytenoid joint surface (facies articularis arytenoidea) is convex, of significant size and ellipse-shaped. The thyroid joint surface (facies articularis thyroidea) occurs as a very shallow hollow, as the cricothyroid joint (articulatio cricothyroidea) is a syndesmosis, without a real joint cavity. Whereas the cricoarytenoid joint (articulatio cricoarytenoidea) has a quite big joint cavity and a thick spacious joint capsule (capsula articularis).

Fig. 5. Cattle larynx. Right side. The thyroid cartilage plate removed on the right side. Centimetre measure. Marking: 1. front corner of the thyroid cartilage, 2. symphysis of the plates of the thyroid cartilage, 3. 4-cornered membrane, 4. elastic cone, 5. vocal process of the right arytenoid cartilage, 6. trachea, 7. stump of the back process of the thyroid cartilage

Fig. 6. The thyroid cartilage of a heifer. Stomach view. Centimetre measure. Marking: 1. front corner, 2. plate, 3. back corner, 4. back thyroid incisure

Fig. 7. The thyroid cartilage of a heifer. Front view. Centimetre measure. Marking: 1. plate, 2. internal surface of the plate symphysis, 3. front corner

Fig. 8. The cricoid cartilage of the cattle. Left side view. Centimetre measure. Marking: 1. arch, 2. plate crest, 3 the arytenoid joint area, 4. the cricoarytenoid syndesmosis area

The arythenoid cartilages (cartilagines arytenoideae) are high, sleek, with well developed cone-shaped processes. However, the difference between the hyaline cartilage of the arytenoid cartilage and the elastic one of the corniculate cortilage (vartilago corniculata) is unclear. The muscle process (processus muscularis) is very short and there is a spacious concave cricoid joint area (facies articularis cricoidea) to the back of it. The vocal process (processus vocalis) is long, cone-shaped and strong (Fig. 9). The epiglottic cartilage (cartilago epiglottica) is low and wide. It does not make even half of the perimeter, however it possesses a clearly shaped and prominently put forward pedicle (Fig. 10).

Fig. 9. Left arytenoid cartilage of cattle, medial view. Centimetre measure. Marking: 1. cone process, 2. vocal process, 3. cricoarytenoid ligament, 4. the cricoid joint area, 5. muscle process

Fig. 10. Epiglottis of a heifer larynx. Right back view. Centimetre measure. Marking: 1. free edge of the epiglottis, 2. pedicle, 3. larynx surface

Fig. 11. Comparison of size structures of larynges of minor and adult cattle. Centimetre measure. Marking: A. the thyroid cartilage, B. the cricoid cartilage, C. the epiglottic cartilage, D. the arytenoid cartilage, 1. adult , 2 minor

The elastic cone (conus elasticus) and the thyroarytenoid muscle (musculus thyroarytenoideus) are strongly developed (Fig 5). The parenchyma of this muscle is 1 cm wide. There is no space between bottom edge of the thyroid cartilage and the ring of the cricoid one (Fig.5). The attachment of the vocal ligament (ligamentum vocale) lies low, just above the bottom edge of the thyroid cartilage.

The results of the measurements of cattle larynges are shown in Table 2. Significant influence of sex on size parameters included in the table was proved when α = 0.05. Important differences between minor males and females were found for the following parameters: 1i and 5c, whereas for adults the differences were found for 1b, 1c, 1f, 1h, 4b.

Table 2. The results of the measurements of the selected size parameters of bovine larynges. The results in relation to parameters 1i, 2g and 2i are in mm2, the rest in mm

parametr	minors n=13									adults n=14
	males n=7				females n=6					males n=7				females n=6
		SD	min	max		SD	min	max	temp		SD	min	max		SD	min	max	temp
1a	59.52a	5.16	54.82	69.16	56.08a	4.65	51.94	64.12	0.871	70.43a	8.75	62.32	84.66	64.08a	4.53	59.91	73.12	1.597
1b	58.24a	4.28	51.34	63.42	56.14a	5.06	47.33	62.13	0.811	69.39a	10.11	57.19	81.23	54.65b	4.09	46.09	59.19	3.554
1c	58.51a	5.28	52.03	68.37	56.98a	9.84	46.23	74.70	0.357	67.44a	7.69	57.34	76.96	50.56b	5.74	41.21	57.16	4.530
1d	85.95a	9.48	70.12	98.64	76.96a	6.81	72.11	89.97	1.930	101.3a	16.15	80.34	125.9	89.61a	10.31	75.22	105.6	1.581
1e	66.42a	3.79	62.34	72.83	66.19a	5.39	60.72	75.34	0.090	83.78a	9.77	71.43	96.12	77.02a	6.16	70.13	86.20	1.517
1f	14.91a	2.44	12.33	18.43	16.14a	4.43	10.23	22.87	0.634	23.07a	5.31	16.23	31.77	17.75b	3.32	13.24	22.01	2.204
1g	32.95a	3.26	29.64	38.64	30.79a	3.21	25.30	35.23	1.119	40.40a	8.95	31.46	54.87	32.97a	4.18	26.71	40.12	1.970
1h	92.62a	10.95	79.38	114.6	91.74a	12.53	82.45	115.7	0.135	122.1a	22.51	91.20	156.5	100.6b	8.44	92.31	111.7	2.355
1i	78.41a	8.50	69.71	94.73	91.17b	3.43	87.96	97.20	3.428	88.93a	5.60	82.17	96.43	94.83a	6.81	88.72	109.1	1.687
2a	37.61a	3.61	32.27	43.75	36.71a	3.86	32.42	42.18	0.434	42.22a	5.60	34.28	49.89	44.19a	7.39	36.92	56.13	0.533
2b	17.15a	2.12	13.90	20.08	16.01a	2.87	11.89	19.87	0.823	19.41a	2.85	16.72	23.75	19.23a	5.75	14.08	28.70	0.069
2c	51.66a	7.03	43.53	65.23	49.88a	7.24	42.12	59.10	0.449	62.64a	8.78	50.12	72.90	58.23a	4.23	53.24	64.42	1.184
2d	74.13a	6.66	64.48	82.79	73.71a	5.66	66.70	82.34	0.121	88.68a	11.56	74.53	105.8	86.60a	6.91	78.12	97.13	0.401
2e	1587a	326.4	1029	1970	1467a	216	1135	1776	0.766	1991a	410	1468	2525	1780a	127	1542	1938	1.299
2f	52.91a	4.41	45.48	58.91	52.42a	4.10	47.24	58.32	0.206	66.73a	8.13	57.23	78.06	60.73a	5.68	55.83	72.89	1.562
2g	30.28a	1.62	28.66	33.21	33.22a	3.61	30.45	38.91	1.948	34.22a	1.50	31.69	36.02	32.91a	1.63	30.09	34.82	1.497
2h	69.53a	4.34	63.48	75.70	70.34a	5.85	63.85	78.83	0.286	84.25a	10.22	71.92	97.97	81.25a	6.52	75.86	94.15	0.641
2i	20.60a	1.86	18.46	23.77	20.57a	1.77	18.84	23.45	0.030	20.21a	1.81	18.16	23.36	21.08a	1.20	19.67	22.43	1.037
3a	36.82a	3.22	32.85	42.31	38.86a	4.33	32.54	45.62	0.974	43.08a	6.25	36.21	52.14	41.70a	3.75	37.12	46.88	0.491
3b	29.69a	2.63	26.68	33.12	27.69a	2.76	24.56	32.80	1.336	34.43a	6.45	27.82	44.60	33.47a	4.69	27.31	40.14	0.310
3c	9.25a	1.26	7.88	11.23	8.32a	1.35	6.71	10.36	1.284	11.18a	2.82	8.41	15.74	9.49a	1.07	8.01	11.16	1.475
4a	42.93a	3.18	37.77	46.12	41.87a	2.97	37.02	45.70	0.617	52.03a	8.06	40.34	64.21	47.95a	3.68	45.02	55.19	1.207
4b	47.80a	4.62	40.11	54.78	45.62a	5.02	40.52	55.21	0.815	60.13a	7.92	50.62	72.88	47.71b	4.84	40.52	54.59	3.474
5a	129.7a	11.09	110.3	141.9	120.0a	8.99	107.3	132.4	1.711	148.6a	22.67	130.2	180.4	141.6a	15.28	123.9	167.5	0.062
5b	27.26a	3.67	23.66	34.25	29.59a	4.32	25.76	36.70	1.052	36.60a	5.94	28.97	46.08	34.79a	3.24	31.83	39.91	0.697
5c	37.96a	3.41	32.50	42.36	29.55b	3.00	26.07	33.28	4.680	40.70a	7.76	31.21	52.83	34.73a	2.81	30.96	37.50	1.906
t 0.05, 11= 2.201										t 0.05, 11= 2.201

Table 3. The results of calculations of indicators characterizing proportions of bovine larynges grouped according to age and sex

successive indicator	way of calculating	minors n=13									adults n=14
		males n=7				females n=6					males n=7				females n=7
			SD	min	max		SD	min	max	temp		SD	min	max		SD	min	max	temp
The thyroid	cartilage
1	1f/1h	0.16a	0.04	0.11	0.21	0.17a	0.03	0.12	0.20	0.502	0.19a	0.01	0.18	0.20	0.18a	0.04	0.13	0.21	0.643
2	1g/1h	0.36a	0.06	0.27	0.44	0.34a	0.06	0.27	0.42	0.599	0.33a	0.02	0.29	0.35	0.33a	0.05	0.29	0.42	0.0
3	1h/1d	1.09a	0.20	0.88	1.40	1.19a	0.09	1.09	1.29	1.126	1.20a	0.04	1.14	1.24	1.13b	0.07	1.05	1.23	2.297
4	1h/5a	0.72a	0.09	0.63	0.84	0.76a	0.09	0.67	0.87	0.799	0.81a	0.08	0.70	0.87	0.72a	0.09	0.62	0.84	1.997
5	1b/1c	1.00a	0.11	0.91	1.18	1.01a	0.19	0.78	1.23	0.118	1.03a	0.06	0.92	1.08	1.09a	0.06	1.00	1.17	1.870
The cricoid	cartilage
6	2c/2d	0.70a	0.07	0.58	0.79	0.67a	0.06	0.60	0.76	0.821	0.71a	0.03	0.67	0.74	0.67a	0.04	0.63	0.74	2.116
7	2b/2d	0.23a	0.02	0.22	0.27	0.22a	0.03	0.16	0.24	0.718	0.22a	0.02	0.20	0.24	0.22a	0.06	0.18	0.31	0.0
8	2f/2d	0.72a	0.06	0.62	0.78	0.71a	0.04	0.64	0.77	0.346	0.75a	0.01	0.74	0.77	0.70a	0.06	0.63	0.77	2.175
9	2h/2d	0.94a	0.04	0.88	0.98	0.95a	0.03	0.91	0.98	0.502	0.95a	0.02	0.93	0.97	0.94a	0.03	0.91	0.97	0.733
10	2c/5a	0.40a	0.06	0.35	0.49	0.41a	0.04	0.37	0.47	0.346	0.41a	0.03	0.37	0.45	0.41a	0.03	0.38	0.45	0.0
11	2a/2d	0.51a	0.02	0.48	0.53	0.50a	0.03	0.46	0.53	0.717	0.48a	0.01	0.46	0.49	0.51a	0.06	0.46	0.60	1.304
The arytenoid	cartilage
12	3b/3a	0.81a	0.06	0.71	0.91	0.72b	0.07	0.61	0.83	2.498	0.80a	0.05	0.74	0.86	0.81a	0.14	0.59	0.96	0.178
13	3c/3a	0.25a	0.03	0.20	0.28	0.21b	0.02	0.19	0.23	2.772	0.26a	0.04	0.21	0.30	0.23a	0.04	0.20	0.28	1.403
14	3a/5a	0.28a	0.02	0.26	0.32	0.32b	0.03	0.26	0.35	2.870	0.27a	0.01	0.27	0.28	0.30b	0.02	0.27	0.34	3.549
The epiglottic	cartilage
15	4a/4b	0.90a	0.08	0.82	1.01	0.92a	0.09	0.83	1.06	0.424	0.86a	0.05	0.80	0.91	1.01b	0.10	0.90	1.13	3.549
16	4a/5a	0.33a	0.03	0.30	0.37	0.35a	0.02	0.32	0.38	1.386	0.35a	0.03	0.31	0.37	0.34a	0.03	0.30	0.38	0.624
True	glottis
17	5b/5c	0.72a	0.09	0.58	0.81	1.01b	0.14	0.80	1.14	4.515	0.92a	0.19	0.74	1.11	1.00a	0.08	0.90	1.12	1.030

Most of the basic parameters was significantly correlated, therefore the bigger is the size of the larynx, the bigger its particular elements became.

The calculated indicators are shown in Table 3. Analysis of the data included in the tables showed that sex had a significant influence on some of them. Age did not influence these proportions. The influence of sex was true for the following parameters 12, 13, 14 and 17 for minors and 3, 14, 15 in adults.

DISCUSSION

Anatomical description of bovine larynx, made in this work, is generally in agreement with available textbooks [4,9], however it yields some new data, especially as far as the soft structures (elastic cone, muscles) are concerned. All the measurements of the larynx cartilages, their proportions and reciprocal relations are however a novelty and hadn't been cited in available literature.

The statistical analysis of the results of the larynx measurements showed that some of the size parametres (1b, 1c, 1f, 1h, 1i, 4b and 5c) were significantly different between groups distinguished according to sex. In all the cases both for minors and adults higher values of the parameters were observed for males, except for 1i which showed higher value for females. Therefore the angle of the thyroid cartilage was significantly bigger for females, as it is observed in humans [5,6]. The length of the thyroid cartilage measured in the median line (1a), distance between the front corners (1b), distance between the back corners (1c), maximum width of the thyroid cartilage (1d) and height of the back corner (1g) show that the male thyroid cartilage is generally wider than that of females.

Analysis of the data in Table 3 showed that significant influence on larynx proportions applied only to sex, therefore age does not have any influence on larynx proportions. The influence of gender applied to 12, 13, 14, 17 for minors and 3, 14, 15 for adults. Therefore one could state that in young individuals proportions of arytenoid cartilage and rima glottidis differ males and females. In adult animals these differences however are not significant. The only one parameter significantly differ male and female larynges in both age groups: it is a relative height of arytenoid cartilage.

CONCLUSIONS

On the basis of the conducted research it is possible to state that cattle laryges present sexual dimorphism, characterized by several basic linear as well as angular parameters and by several proportions. The proportions, however, which differ the genders, are not the same in young and adult animals, so certain important changes in laryngeal framework during maturation process occur.

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Accepted for print: 29.02.2008

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Jarosław Wysocki
Vertebrates Morphology Department
of University of Humanities and Sciences in Siedlce, Poland
B. Prusa Str. 14, 08-110 Siedlce, Poland

Ewa Kielska
Vertebrates Morphology Department
of University of Humanities and Sciences in Siedlce, Poland
B. Prusa Str. 14, 08-110 Siedlce, Poland

Anna Charuta
Vertebrates Morphology Department
of University of Humanities and Sciences in Siedlce, Poland
B. Prusa Str. 14, 08-110 Siedlce, Poland
email: anna.charuta@neostrada.pl

Izabela Janiuk
Vertebrates Morphology Department
of University of Humanities and Sciences in Siedlce, Poland
B. Prusa Str. 14, 08-110 Siedlce, Poland

Jerzy Reymond
Department of Maxillofacial Surgery,
Regional Hospital of Radom, Poland
Tochterman Str. 1, 26-600 Radom, Poland

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Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.

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