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Atlas of Human Embryos Chapter   Figure

C-2 dermatome, C-2 neural crest, c-1 dermatome, caudal part of primitive pharynx, dorsal thalamus, epithalamus, hypothalamus, mandibular prominence of pharyngeal arch 1, maxillary prominence of pharyngeal arch 1, optic cavity, optic stalk, optic vesicle, pharyngeal arch 2, pharyngeal groove 1, pharyngeal pouch 5, placode, primitive oral fissure, prosencephalon (diencephalic part), sternocleidomastoid / trapezius premuscle mass, stomodeum, sulcus limitans, truncus arteriosus, ventral thalamus

A section through the C-2 neural crest, truncus arteriosus and the ventral part of branchial arches 1 and 2.

Observe:
1. The close relation between the prosencephalon and the overlying ectoderm.
2. The optic stalk that will become the optic nerve connecting the optic vesicle to the diencephalic part of the prosencephalon.
3. Branchial arches 1 and 2 filled with mesenchymal cells and the disappearance of the more caudal smaller arches.
4. The caudal extent of the fifth pharyngeal pouch.
5. The caudal part of the pharynx becoming a vertical slit where it is continuous with the tracheoesophageal tube in Section 14.


Keywords: C-2 dermatome, C-2 neural crest, c-1 dermatome, caudal part of primitive pharynx, dorsal thalamus, epithalamus, hypothalamus, mandibular prominence of pharyngeal arch 1, maxillary prominence of pharyngeal arch 1, optic cavity, optic stalk, optic vesicle, pharyngeal arch 2, pharyngeal groove 1, pharyngeal pouch 5, placode, primitive oral fissure, prosencephalon (diencephalic part), sternocleidomastoid / trapezius premuscle mass, stomodeum, sulcus limitans, truncus arteriosus, ventral thalamus

Source: Atlas of Human Embryos.