A section through the C-5 spinal ganglion and the conus swellings of the heart.
Observe:
1. The vagus nerve lateral to the esophagus and trachea.
2. The pulmonary artery ventral to the trachea.
3. The phrenic nerve lateral to the right atrium.
4. The septum primum and septum secundum between the right and left atria.
5. The olfactory fila between the olfactory epithelium and the primordial tuberculum olfactorium.
Keywords: C-5 spinal ganglion, alar plate, basal plate, blood cells, bulboventricular sulcus, cerebral vesicle, edge of shoulder, esophagus, frontonasal area, lateral nasal elevation, left atrium, left dorsal aorta, left ventricle, left ventricular chamber, medial nasal elevation, notochord, olfactory epithelium, olfactory filia (CN I), phrenic nerve, primary interatrial septum (septum primum), primordial cornu Ammonis, primordial gyrus dentatus, primordial tuberculum olfactorium, right and left conus swellings, right atrium, right pulmonary artery, right ventricular chamber, septovalvular space, septum secundum, septum spurium, sympathetic chain, telencephalon medium, trachea, transverse sinus, vagus nerve (CN X)
Source: Atlas of Human Embryos.