![](/drem/stage19/labels2/S121L.gif)
![alar plate(s), basal plate, cerebral aqueduct (mesocoele), endolymphatic duct, isthmus of rhombencephalon, obex, rhombencoel (fourth ventricle), roof plate, sulcus limitans, trochlear nerve (CN IV)](/drem/stage19/Z0/S121N.jpg)
![](/drem/rulerbg.png)
0 μm
Carnegie Embryo #9325 | Location: 4-3-3
Keywords: alar plate(s), basal plate, cerebral aqueduct (mesocoele), endolymphatic duct, isthmus of rhombencephalon, obex, rhombencoel (fourth ventricle), roof plate, sulcus limitans, trochlear nerve (CN IV)
Source: The Virtual Human Embryo.