<p class="abstract"><strong>Background:</strong> The larynx besides being used in respiration, performs the function of production of voice. A thorough knowledge of relevant surgical anatomy is a must for any surgeon before performing laryngeal framework surgery (LFS). Most of the relevant anatomic details for LFS are based on Western population and the studies based on Indian population are extremely scarce. We propose to undertake this study in order to understand the relevant anatomy of the thyroid cartilage in adult Indian population and to compare these dimensions with those studied in the western population as available in literature.</p><p class="abstract"><strong>Methods:</strong> Fifty-two samples of adult thyroid cartilage (35 males and 17 females) taken from cadavers were analysed. Digital Vernier callipers &amp; goniometer were used to take morphometric measurements of the Thyroid cartilage to see for normal variation, sex differences and bilateral asymmetry. Observation were analysed by calculating mean &amp; SD.  </p><p class="abstract"><strong>Results:</strong> Most parameters measured in thyroid cartilage did not show significant difference in males &amp; females. All the parameters of thyroid cartilage except thyroid angle were higher in males than females. Bilateral asymmetry in the size of thyroid lamina was seen in majority of specimens though not statistically significant.</p><p class="abstract"><strong>Conclusions:</strong> The detailed study of thyroid cartilage in the form of morphometric parameters of thyroid cartilage is useful for anatomists, radiologists, reconstructive and ENT surgeons. Comparison with other populations in the world reveals that the absolute values differ in different populations which could be due to differences in body built, racial differences and age group of cadavers.</p>

<p class="abstract"><strong>Background:</strong> Surgical cricothyroidotomy is used to rapidly gain entry into the subglottic airway by creating an opening in cricothyroid membrane. The size and position of cricothyroid membrane is variable depending on racial characteristics of the individual. Statistics regarding dimensions of cricothyroid membrane has been documented extensively in Caucasian race. This study aims to augment the meagre information available on the Indian population on this important part of upper airway.</p><p class="abstract"><strong>Methods:</strong> Morphometric cadaveric analysis done in tertiary health care centre. 39 adult human cadaveric larynges were obtained for this study. Using electronic Vernier caliper, different dimensions of cricothyroid membrane and depth of subglottis were noted down in predesigned proforma in standard office software. Data obtained was collated and compared with existing literature.  </p><p class="abstract"><strong>Results:</strong> The average dimensions of cricothyroid space and cricothyroid membrane were uniformly larger in males compared to females. Mean middle width F: 10.92±1.57 mm, M: 13.84±2.54 mm; mean height F: 7.26±1.82 mm, M: 9.61±1.86 mm; mean thickness F: 2.89±0.22 mm, M: 4.53±0.92 mm and mean subglottic depth F: 17.24±2.09 mm, M: 21.94±2.93 mm.</p><p class="abstract"><strong>Conclusions:</strong> Inter specimen disparity was noted. As cricothyroid membrane is smaller in Indian population compared to Caucasian population, ET tubes size 3.0 to 5.0 in females and 4.0 to 6.0 in males are suggested for use for cricothyroidotomy. Oversized tubes are known to cause dysphonia, laryngeal damage and subglottic stenosis.</p>

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Cricoid cartilage is the only complete ring that surrounds the airway completely. Although it is smaller than thyroid cartilage and does not house any important structures like the thyroid cartilage (vocal folds), it forms an important cog in the upper airway. Renewed interest in subglottic stenosis recently has underscored the importance of detailed knowledge of cricoid cartilage. This study aims to augment the meagre information available on this important part of upper airway. </span></p><p class="abstract"><strong>Methods:</strong> Study design was on morphometric analysis and the setting was at tertiary health care centre. <span lang="EN-IN">Thirty one adult human cadaveric larynges were obtained for this study. Using an electronic vernier caliper, different morphometric parameters of all the cricoid cartilages were noted down in a predesigned proforma in standard computer office software. The data thus obtained was collated and compared with existing literature.  </span></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">The average inner transverse diameter (F: 15.05±1.02 mm; M: 17.52±2.64 mm) is greater than the average inner antero-posterior diameter (F: 12.71±0.45 mm; M: 14.11±2.55 mm). The average height of cricoid arch was F: 6.50±0.68 mm; M: 7.69±0.63 mm and the average height of cricoid lamina was F: 18.38±0.61 mm; M: 21.17±2.31 mm. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">Inter specimen<strong> </strong>disparity was noted in the various dimensions measured in the cricoid cartilages. The average transverse diameter was greater than the average antero-posterior diameter giving the cartilage an ovoid shape in nearly all specimens. Morphometrical data of the cricoid cartilage may be very useful in endotracheal intubation, laryngeal microsurgery and laryngeal framework surgery. These parameters can be helpful in evaluation of subglottic stenosis and its surgical repair.</span></p><p> </p>

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