. Human embryology and morphology. Embryology, Human; Morphology. DEVELOPMENT OF THE PHARYNX AND NECK. 29 off vessels to the gills, in which the blood is arterialized. In the human embryo the blood passes directly through the aortic arches. All that part of the human neck lying in front of the vertebral column and between the mouth above and the thorax and clavicles below, with the bounding walls of the adult pharynx, is formed from the foetal visceral arches. A knowledge of the. nasal pit artery of 1st arch artery of 2nd arch gill cleft ventral aorta gill cleft artery of 4th arch ventral aort
. Human embryology and morphology. Embryology, Human; Morphology. DEVELOPMENT OF THE PHARYNX AND NECK. 29 off vessels to the gills, in which the blood is arterialized. In the human embryo the blood passes directly through the aortic arches. All that part of the human neck lying in front of the vertebral column and between the mouth above and the thorax and clavicles below, with the bounding walls of the adult pharynx, is formed from the foetal visceral arches. A knowledge of the. nasal pit artery of 1st arch artery of 2nd arch gill cleft ventral aorta gill cleft artery of 4th arch ventral aorta bulbus arteriosus ventricle auricle Fig. 21B.—Showing the position of the Heart, Visceral and Aortic Arches in a fish. (Diagrammatic—after Gegenbaur.) transformation of the foetal to the adult pharynx is of the utmost practical importance: it explains the occurrence of fis- tulae and cysts found in the neck; it accounts for the peculiar courses taken by nerves, such as the recurrent laryngeal and phrenic; it explains the peculiar distribution of nerves to the pharynx; and throws light on the nature and anomalies of the thymus, thyroid and tonsil. The Branchial or Visceral Arches.—The visceral arches bound and form the whole thickness of the wall of the primitive pharynx. Four arches, each bounded behind by a depression, are to be recognised superficially on each side of the pharynx of the fourth week human embryo (Fig. 21^4), but behind the 4th cleft is a fifth arch, perhaps also a sixth which, however, never become raised or superficially differentiated. 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
