ANTHROPOMETRİCAL FEATURES OF LARYNGEAL CARTİLAGES.

G. S. LONGIA

Department of Anatomy, M.L.B. Medical College, Jhansi, India

LARINKS KIKIRDAKLARININ ANTROPOMETRİK ÖZELLİKLERİ

Özet

Larinkse biçimini veren ve fonksiyonunu sağlayan çok sayıda kılmdak ile bunlara yapışık kaslar vardır. Bu araştırmada, 20·60 yaşlarında, boyları 135·161 cm arasında ve ağırlıkları 40·72 kg olan 58 erkek ve 21 kadının larinks kıkırdakları incelendi. Patolojik değişimler gösteren ve anomalisi olan larinks olguları çalışma

kapsamı dışında bırakıldı. !ncelemelerimiz sırasında çeşitli ölçümler yapıldı. Superior tiroid çenıiğinin

derinliği ile laminaların uzunluğu ve genişliği erkeklerde kadınlara oranla belirgin biçimde yüksek bul undu (p<0.05); buna karşın, tiroid açısı kadınlarda daha yüksek değerler verdi (erkeklerde 43·100 , ortalama 90 ;

kadınlarda 85·126, ortalama 120 ; p<0.005). Tiroid açısının tek başına kullanılmasıyla bile olguların %90'ında cinsiyet ayırırnı yapılabileceği görüldü. Kırılmış kıkırdaklar üzerinde yapılan çeşitli ölçümlcrin

cinsiyete özgü dimorfizm gösterdikleri saptandı; bu tür olgulardaki cinsiyet ayırımı %62-64 doğrulukıa sonuçlar verdi. Aritenoid kıklfdağın genişliği ile epiglot kıkırdağının uzunluk ve derinliği kadınlara oranla

erkeklerde belirgin biçimde yüksek değerler gösterdi. Larinks kıkırdaklanndaki çeşitli boyutların ölçümlerinin,

adli tıp açısından cinsiyet tayininde önemli yardımları olabileceği sonucuna varıldı. Bu araştırınadaki ölçümlerin, kişilerin yaşları ve boyları ile ilgisi bulunmadı.

Summary

in the present study, 58 male and 21 female laryngeal cartilages were examincd and various measurcmcnts recorded. Depth of superior thyroid notch: length and breadth of laminae wcre significanıly greatcr in males than females (p<0.05), while thyroid angle was higher in females (p<0.005). Sex of the individual could be

idenıified only from the thyroid angle in 90 percent of the cases. Various measurements of cracked cartilage

showed sexual dimorphism. Sex could be identified in 62 to 64 percent of the cases. Breadıh of arytenoid

cartilage and length and breadth of epigloııic cartilage were significantly higher in males than in females.

'llıese measurements may be of immense help for medico-legal purposes for determinatian of sex.

Key words : Laryngea/ carıilages . Anıhropomelrica/ measuremenls . Sex idenıificaıion

142 G.S. LONGIA

INTRODUCTION

The larynx is formed by various cartilages, viz; thyroid, cricoid, arytcnoid, corniculate, cuneiform and epiglottis, which maintain its shape, check its collapse and

give attachment to various muscles. Conditions like post··intubational stenosis or

subglottic stenosis arouses curiosity to determine the various anthropometrical features of these cartilages. The literature available on the subject is very scanty and whatever is

available, is mainly from western countries. Frable (1) and Kirchner and Wyke (2) have worked on the movement of joints of cartilages. Negus (3) and Terracal et al (4) have described the functional anatomy of the larynx and its cartilages. Too-chung and Green (5) studied various measurements of the cracked cartilage in neonates to 15 years of age to study the rate of growth of the cartilage. Some anthropometrical measurements of the thyroid, cracked and arytenoid cartilages have been described in text books by Hollinshead (6), Schaeffer (7), Warwick and Williams (8) and Schafer et al (9).

In an endeavor to further supplement the details in the existing literature regarding anthropometrical study of various cartilages of the larynx, this work has been

undertaken in the central part of India.

MATERIALS AND METHODS

For the present study, sixty eight male and twenty one female larynges, were obtained from freshly embalmed bodies available in the Department of Anatomy and post-mortem bodies from the mortuaıy attachcd

LO M.L.B. Medical College Bospital, Jhansi. Laıynges showing pathological changes and abnormalities werc

not included. Age (20-60 years), length (135-161 cm), body weight (40-72 kg), profession and religion werc

also rccorded. One of 68 male cases studies, one was a goldsmith and anothcr was a piper. This has becn purposely mentioned here because their larynges showed the highest measurements.

Various cartilagcs viz; thyroid, cricoid, aıytenoid, comiculate, cuneiform and cpiglottis were carefully

dissected and separated out from each laıynx. These were cleaned and kept in 5 percent formol-saline to avoid dchydration, shrinkage and distortion of the ir normal shapc. Various measurements such as length, breadth, height, antero-posterior and transverse diameters were measured with the help of a sliding caliper, graduatcd in 0.10 mm and also with the help of non-elastic thread, read on the scale in mm. The thyroid angle and depth of

superior thyroid nOlch were measured with the help of a specially designed goniometer. The statc of

ossification of cartilages was also noted.

Sex differcnces in respect to various measurements, if any, were tested for statistical significance by ap

-plying Students ı-test. For each measurement considered, probability of misclassification for the identification of sex was also computed using discriminant function (10).

OBSERV ATIONS

A total of 89 laryngeal carLİlages were studied and details of each of them are given below.

laminae, length of superior et inferior hom, depth of superior thyroid notch thyroid angle and distance between two posterior borders were measured (TabIc i; Figure la, b, c). Lenglh and breadth of both laminae were significantly (p<O.05) higher in males than in females. Depth of superior thyroid notch (t= 4.31; p<O.()05) and thyroid angIc (t=

9.81; p<O.005) showed highly significant difference in the two sexes. Length Qf the lamina was higher than its breadth. Discriminant function was applicd to dcriye probabilities of misclassification for identifying indiYidual's sex, utilizing about measurements considering onlyone at a time. Thcse probabilities for Icngth, dcpth of superiof thyroid notch and thyroid angle were 39, 28.8 and LO percent respectiyeIy (TabIc II).

Table i. Statistical significance of means of vaıious measurcments (in mm) in two scxes for thyroid carlilagc.

Male (n=68) Female (n=21)

Measurcments Range Mean±SD Range Mean±SD ı-Value p-Valııe

Length Right 14-49 29A± 9.4 18-38 24.6± 6.0 2.24 0.05'

Left 14-51 29.6±10A 18-38 24.4± 5.7 2.32 0.05

Breadth Right 10-43 29.6± 7.9 16-37 26.0± 4.8 2.01 O.OS' Left 1l-43 29.6± 7.7 15-37 26.1± 5.0 1.99 0.05*

Length of Right 6-28 LS.2± 4.6 7-27 16A± 4.5 1.05 0.20 supcıior hom Left 6-26 lS.0± 4.5 7-27 16.4± 4.5 1.25 0.20

Right 3-22 9.5± 4.0 5-20 8.7± 3.5 0.82 0.20 Left 4-23 9.5± 4.0 4-20 S.S± 3.6 0.82 020 Distance bctwecn twü 25-44 30.6± 6.9 26-42 28.4± 3.8 1.75 0.05 posteıior border Dcpth of supeıior 4-15 9.5± 3.0 3-12 6.4± 2.5 4.31 0.005** thyroid notch 'Dıyroid anglc 43-100 78.7±10.2 85-126 106.1±14.4 9.81 O.CX))'* (dcgrcc)

144 ;. B [)

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A. Posterior aspect of thyroid cartilage: a-a'depth of inferior thyroid notch, b-b' distance between two posterior borders; B. Inferior aspect of thyroid canilage, c thyroid angle; C. Lateral aspect of thyroid cartilage: d-d' height, e-e' 1ength, f-f' length of superior hom, g-g' 1ength of inferior hom; D. Post eri or aspect of cricoid cartilage, h-h' height ofposterior lamina; E. Anterosupcrior aspect of cricoid carti1age; i-i' transverse diameter, j-j' anteroposterior diameter; F. Lateral aspect of arytcnoid canilage. k-k' height, 1-1' breadth; G. Anterior aspect of epiglottic cartilage; m-m' maximum length, n-n' maximum breadıb.

Cricoid Cartilage

This is thicker and stronger than the thyroid cartilage and is shaped like a signet-ring. Height of anterİor et posterior laminae and transverse and antero-posteriot diame-ters were measure (Table III; Figure Id, c). All the measurements ,were significantly higher in males than in females (p<:O.05). Variations in transverse diameter and heighı of anterior ct posterlor laminae were greater in males than in females. However, It was the reverse for antero-posterlor diameter. Probabilities of misclassification were 35.8, 36.6 and 37.5 for antero-posterior diameter and height of anterior et posterior laminae re -spectivcly (Table II) ..

Breadth was significantly mare in males than in females (p<O.Ol). Probability of

mis-classification was detennined as 36.4 and 36 percent on right and lefl sides respcctively.

Tablc II. Values of discriminant function and associaıed probabiliıics of misclassificaıion for the sclecıed

measurements of various carrilages.

Value Probabiliıy of

Discriminant Comct

Carıilage Variable Punction (d/s) Classificaıion (%)

Length Right 0.55 61 Left 0.55 61 Thyroid Deplh of superior 1.07 ·71.2 thyroid notch Thyroid angle 2.45 90

Antero.-posıerior diameter 0.71 64.2

ericoid Height of anıerior lamina 0.66 63.4

Ikight of posterior lamina 0.61 62.5

Arylhenoid I3readth Right 0.69 63.6

Left 0.70 64.0

Epigloilis Maximum breadth 1.14 71.7

Table III. Statistical values of various measurements (in mm) of cricoid carrilage.

Male (n=6S) Female (n=21)

Measurements Range Mean±SD Range Mean±SD ı-Value p-Value

Anteroposterior 11-40 22.0±5.2 ıo-25 IS.3±5.2 2.S5 0.01* diamcter Transverse diameter 10-35 22.6±7.7 S-32 lS.9±5.7 2.05 0.05* lleight of anıerior lamina 2-8 5.2±1.6 1-6 4.2±1.2 2.88 0.01* Height of posıerior 6-33 21.6±6.0 6-30 IS.1±4.8 2.03 0.05* lamina

146 G.S. LO",(J!iI

Corniculate CartiLa.ge

This canilage is paıred one and in the form of a srnall coniceıl nodule. Maximum diameter was the same in males and females on both the sidcs (Tahlc IV). Carıilage was absent in 7 cases (5 males and 2 females). Abscnce was unilateral in 4 cases (malc Icft side 3 and femille right side 1) and bilateral in 3 cases (males 2 and female 1).

Table IV. Statisıical valııe of various measnremeıılS of aryıcnol.d, cornicnhte and epigloıııc carülage, oJ

larj'nx.

A1ale (n~6S) Female (n ",2 i)

Canlıage Mea;uremcııt Range Mean'±SO R;ı.nge ~1carı±SD [·Value p-Valuc

Right 7-19 13.0i2.9 7-20 ı2.3±3.4 _{093 0.3}

Height

Len 7-18 nO±2.9 7-20 12.2±3.7 1.04 0.2

IIryıenoid

Bre~dıh _{Right 2-14 7.0±2.6 3-9 5.9±2.7 2.69 O.Oi} Lefı 214 7.7i2.7 _3-10 5.9±2.1 3.-/0 0.001"

COTlıicwaıe Mdximum Right 0-7 3.2±1.3 0-6 3A±ı.2 _0.63 0.5

diameter Lefı 0-6 3. HU 06 3.4±1.2 0.95 0.4

----

* Sigrıi.ficanı; ** Highly Sigrıificarıt

33.9±4.5

23.6±4.9

Cunejform and Epiglotıic Cartilages

1-1-4 t 35.2±6.9 6,98 0.00 L **

12-30 18.ı±4.6 _{4.56 0.001"}

Cunciform cartilage is paired and is in the form of a small club shaped oblong body. it is present in about 14 percent of males and 25 percent of females. EpigIolıic cartilagc is broad and roundcd at its upper free ınargirı and poinıcd at its lowa margin. Maximum Iength and breadıh \\'cre statisticaııy higher (p<O.OO1) in males ıhan in females (T::ıblc

In the present sıııdy, all the measurements had no relationslıip wilh age or staturc of the body. On other olher hand, Too-churıg and Green (5) have obscrvcd that cor(mal diameter was more than the sagiltal dinmeter iıı the cricoid eartilage and, both the diameters and height had linear relationship. Sagittal diameter increased fastcr than that of coronal. Various measuremcnts described in different text books on the subject viz; Quain's Elements of Anatomy (9), Gray's text book of Anatomy (8), Mouis' Human

Anatomy (7) and Hollinshead Anatomy for Surgeons (6) are of western po[lulaLion. The

thyroid angle has been described as aboııt 90 degrce.s in males and 120 degrees in females while in the present study, it ranged from 43 degrees to 100 degrees İn males and 85

degrl".es to 126 dcgrecs in females, Thus, from ıhyroid arıgle, only the sex could be

iderıliGed in 90 percent cases (Table II). As shown in Table II, the sex can also be

ideIltified coneetly from clepm of superior thyroid oOLelı and length of lamina in 60 to 70 percent cases. The aULhor could not get any cvidenee of this in the available literature.

Height of anterior and posterior laminae usu:ılly rangcd from 2-3 cm and 5-7 cm respectively in erieoid eartilage as described in various books of anatomy, buL no evirknce is available on sexual dimorphism therein, In this study, the height oflaminae

as well as antero-posterior and transverse di am eter were hıgher in males (Table II!). Sex from these meaSllfcments cou Id be idenlified correcıly in 60-65 percent of the cases,

VariOlıs measuremenls of other cartilages e,g" arytenoid, cuneiform, eomiculate and

epigloltis are not given in liwrature except the height aııe! breadtJı of arytenoid crtilage which are described as 20 mm and 10 mm respectively in Quain's Elements of Anatamy (9). The brcadth of arytenoid cartilage, diameter of comiculatc, and Icngth <uıd breadth of cpiglolLic carLilage were found to be significanLly higlıer in males than that of females (Tab k IV). Sex Lhus can be identi[icd from breadth of arytenoid and epiglottie earLilage in 60-70 percent cases. The presenec of euneiform eartilage as well as comieulate cartilage were highcr in females than those of males. Thus, the prescnı study emphasizes that various anthropometrica! features of laryngeal cartilages have sexual

dimorphism and could be useful in the determimıtion of sex,

Further studies on the subject, however, are required to be undenaken allover the

world to [ind out the racial and other differences in relatıon to sex. This wouıcı be helpf ul in medical jurisprudence.

REFERENCES

Frablc, M.A. (1961) Arch, Oıolaryngol., 73, 551-556,

2 Kirc~ııcr, J.A .• Wyke. B, (1965) Ann. dıaı. Rhinol. Laryngol., 74, 749-768,