A few remarks on the morphogenesis of the larynx.

After having reviewed the principal theories regarding the development of the larynx the authors performed a study on the morphogenesis of the above structure using four horizontally- and sagitally-sectioned human embryos. The conclusion of a study of these sections is that the LC constitutes the primordium of the laryngeal vestibule. From its lateral margin, caudally (Stage 19, Carnegie System), the primitive ventricles begin to form, while in the final stages the EL extends caudally enclosing a small cephalic infraglottic area and therefore completely separating the IG from the LC. Such findings in our opinion would confirm a different embryological derivation of the laryngeal cavity above and below the glottis.

The relationship between parotid and superficial fasciae.

The paper reports a study conducted on serial sections of subcutaneous neck and facial tissues taken from ten human fetuses with a craniocaudal distance of between 7 and 30 cms for the purpose of establishing the age at which various anatomical structures develop and interact. In particular, the study was aimed at investigating the relationship between the parotid and superficial fasciae. Findings, supported also by direct observations on humans, demonstrated that a parotid fascia proper does not exist. The study was also aimed at confirming or invalidating the contrasting opinions reported in recent literature. On the basis of our observations on the parotid gland, no parotid fascia as such seems to be present, but rather a superficial thickening of the connective tissue with muscle fibres which can be identified with the superficial fascia of the region and as a continuation of the platysma m., and with the septa subdividing the gland. Moreover, only a thin connective layer was detected in the deep surface of the fascia. These findings are in line with those reported by Jost who, like ourselves, conducted his research on both primates and humans. The anatomical and surgical implications of these findings are considerable as they entail a redefinition of the existence of a parotid fascia. In particular, this implies abandoning the expression introduced by Mitz who defines this structure as representing a "superficial muscular and aponeurotic system (SMAS)" which in fact can be considered to correspond to the superficial fascia as correctly described by Sterzi and subsequently confirmed by Bertelli.(ABSTRACT TRUNCATED AT 250 WORDS)