Sulcus limitans

In the fourth ventricle floor, the sulcus limitans separates the cranial nerve motor nuclei (medial) from the sensory nuclei (lateral).

In the superior part of the rhomboid fossa, it corresponds with the lateral limit of the fossa and presents a bluish-gray area, the locus ceruleus (which owes its color to an underlying patch of deeply pigmented nerve cells, termed the substantia ferruginea). The sulcus limitans can also be located by searching laterally from the medial eminence. It is parallel to the median sulcus.

Fourth ventricle floor: fc: facial colliculus; ht: hypoglossal triangle; if: inferior fovea; me: medial eminence; ms: median sulcus; o: obex; sf: superior fovea; sl: sulcus limitans; sm: medullary striae of fourth ventricle; vt: vagal triangle.