Age characteristics of the larynx in infants during the first year of life

Background and Purpose: Investigations of the larynxes in thyrty infants during the first year of life of both sexes, randomized trial, were performed by morphological and histologic analysis. Morphometric parameters of the larynx as: length (anterolateral parameter), width (transverse parameter) and thickness (anteroposterior parameter) were determined. These parameters determine the size and shape of the larynx. The repciprocal relation parameters which determinate size of the larynx in infants and the body length are in high correlation. Therefore, the equation for calculating the size of the larynx out of the body heght was founded. Histologic characteristics of the laryngeal cartilage are constant. They indicate evident changes, that are the basis for approximate determination of a child’s age. Materials and Methods: The organs of the infants were taken from pathoanatomical autopsies. None had changes in the respiratory system. The major methods of the investigatio were anatomical macrodissection, morphological and histologic analysis and statistics. Results: The average body length in infants was 540 ± 20 mm (54 ± 2cm) and the average larynx length was 11.9± 0.3 mm. There was a correlation between these parameters p ‹ 0.01 (r = 0.75). The average value of the width of the larynx in infants was 17.7 ± 0.5 mm. The width of the larynx was in correlation with the body length p ‹ 0.01 (r = 0.79). The average value of the thickness of the larynx was 12.6 ± 0.4 mm. This parameter was correlated with the body length p < 0.01 (r = 0.82). Histological analyses results of our investigation, cartilage of the larynx in infants, show that hyalin structure is the result of age changes. Conclusion: Quantitative anatomical knowledge on the larynx in the pediatric population are necessary for the clinical orientation, particularly for choosing a suitable endotracheal tube. Size of the larynx in prematures, neonates and small children, constantly follows the external body dimensions, particularly the body height, that is confirmed by the correlation factor in its highest value. They indicate evident changes, that are the basis for approximate determination of a child’s age. Hyalin structure is in correlation to the children’s age.