. Human embryology and morphology. Embryology, Human; Morphology. 256 HUMAN EMBRYOLOGY AND MORPHOLOGY. the foramen ovale starts to close and the ductus arteriosus begins then to contract, and within the 1st month becomes reduced to a fibrous cord. The ductus arteriosus represents the dorsal segment of the 5th left arch; the corresponding part of the right 5th arch disappears soon after it is formed. The Larynx.—The larynx is developed in the fiopr of the pharynx out of the basal part of the pulmonary diverticulum. The origin of the upper aperture of the larynx has been already described (page
. Human embryology and morphology. Embryology, Human; Morphology. 256 HUMAN EMBRYOLOGY AND MORPHOLOGY. the foramen ovale starts to close and the ductus arteriosus begins then to contract, and within the 1st month becomes reduced to a fibrous cord. The ductus arteriosus represents the dorsal segment of the 5th left arch; the corresponding part of the right 5th arch disappears soon after it is formed. The Larynx.—The larynx is developed in the fiopr of the pharynx out of the basal part of the pulmonary diverticulum. The origin of the upper aperture of the larynx has been already described (page 250). It is probable that the thyroid cartilage represents the skeletal parts of the 4th and 5th visceral arches, but this cannot be regarded as settled. There is no interval to be recognised between the hyoid bone and thyroid cartilage in the earlier stages of development. By some, the epiglottis is believed to be a derivative of the fifth arch. Only in man and the higher anthropoids are the true vocal cords covered by stratified epithelium; but all the muscles of the human larynx are represented in the larynx of the ape, but in a less specialized condition. left. cms. __ right ensiform Fig. 210.—Diagram of the Diaphragm to show the Parts formed by each of the five Elements. Occasionally the saccule of the larynx, a development from the apex of the ventricle, may protrude through the thyro-hyoid membrane, thus giving rise to an air cyst in the neck. Such. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Keith, Arthur, Sir, 1866-1955. London : E. Arnold
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
