Description of human fetal laryngeal functions: phonation.

Here presented are the different human fetal larynx functions. Analysis and observation of the organ show at least three behavioural patterns: swallowing, respiratory and phonetic. The respiratory function coincides with a blood aspiration through the venosus duct (phenomenon measured by pulsed Doppler) which increases the amount of oxygenated blood in brain circulation that comes from the placenta. The phonetic function is presented setting down the requirements for its recognition. Phonetic function is observed after the 18th week of fetal life and can be considered to be a demonstration of cerebral cortex activity in the fetus.