The larynx is suspended posteriorly at the skull by constrictor muscles, and attached anteriorly to hyoid bone and mandible by: Thyrohyoid Diagastric Stylohyoid Geniohyoid Mylohyoid muscles. On sagittal section the infant larynx is located at the level of third or fourth cervical vertebra and it starts to descend at around two years of age reaching the level of 6th or 7th cervical vertebra by adulthood. Physiologically , the new-born is similar to non-human primates. The tip of epiglottis rests behind the soft palate in both the species.
This anatomical situation allows both simultaneous breathing and suckling without any risk of aspiration, also explaining preferentially nasal breathing and absence of articulated speech. Infant larynx is approximately one-third of adult larynx. The infant thyrohyoid membrane is much shorter and the thyroid notch is behind the hyoid. The thyroid…
