C1-C7: Beginning of trachea, oesophagus. Nasal placodes (nasal pit forming on one side). Forebrain. note proximity of nasal pit to prosencephalon (future site of olfactory nerve). In C2-C4, identify the medial and lateral nasal swellings.
C4: Common cardinal vein in the posterior wall of the intraembryonic coelom - the pleuropericardial folds which contribute later to the formation of the pleura and pericardium. L. nasal pit. In C4, junction of R common cardinal vein with dorsal wall of sinus venosus.
C1-5: Forebrain. Also identify the sulcus limitans separating the alar and basal plates.
The Carnegie stage 13/14 Pig Embryo is 6mm in size and approximately equal to day 42 Human Embryo. Use the serial images to identify internal features and relationships that exist within the embryo at this stage. Then compare these images with the external appearance of the embryo at this stage and the later internal features of the stage 22 embryo.
Note that the nomenclature "stage 13/14" is not an actual Carnegie stage but indicates that the embryo stage lies between or has features of both stage 13 and stage 14 embryos.
Levels shown on whole embryo are only approximate.
Note that not all embryo features are labelled.
Hint: clicking on each section image above will also step you through the whole embryo in sequence.