File:Bailey098.jpg

Fig. 98. Ventral view of head of 13.7 mm human embryo

His.

Associated text

"Further development consists essentially of fusions between the various elements already present and of changes in the relative proportions of these elements. The two medial nasal processes come close together to form a single medial process which gives rise to the middle portion of the upper lip and the adjacent portion of the nasal septum (Figs. 98 and 99). The maxillary process expands generally to form the cheek and lateral portion of the upper lip and at the same time fuses with the nasal processes. This fusion obliterates the naso-optic furrow and shuts off the connection between the nasal pit and mouth slit (Figs. 98 and 99). Internally the concomitant formation of the palate separates the oral and nasal cavities. The lateral nasal process gives rise to the wing of the nose. The nose at first is a broad, flat structure but later becomes elevated, elongated and narrower. The lower jaw, lower lip and chin are formed by the mandibular processes. At first the chin is short vertically but broad transversely. Later it becomes longer and a transverse furrow divides the middle portion into the lower lip and chin."

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Reference

Bailey FR. and Miller AM. Text-Book of Embryology (1921) New York: William Wood and Co.

Cite this page: Hill, M.A. (2024, April 18) Embryology Bailey098.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Bailey098.jpg

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