Henry Gray (1825–1861). Anatomy of the Human Body. 1918.
pages 73
| the dorsal end of the septum transversum the lung buds come to lie above the septum and thus pleural and peritoneal portions of the pleuro-peritoneal cavity (still, however, in free communication with one another) may be recognized; the pericardial cavity opens into the pleural part. |
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FIG. 55– Upper part of celom of human embryo of 6.8 mm., seen from behind. (From model by Piper.) (See enlarged image) |
| The ultimate separation of the permanent cavities from one another is effected by the growth of a ridge of tissue on either side from the mesoderm surrounding the duct of Cuvier (Figs. 54, 55). The front part of this ridge grows across and obliterates the pleuro-pericardial opening; the hinder part grows across the pleuro-peritoneal opening. |
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FIG. 56– Diagram of transverse section through rabbit embryo. (After Keith.) (See enlarged image) |
| With the continued growth of the lungs the pleural cavities are pushed forward |