Floor of 4th ventricle has ?

Floor of 4th ventricle (Rhomboid fossa) It is diamond or rhomboidal shaped and is formed by posterior surface of pons (upper triangular pa or pontine pa) and dorsal surface of medulla (lower triangular pa or medullary pa) junction of pons and medulla forms intermediate pa. Features of 4th ventricle are :? Median sulcus (a midline groove) divides the floor into two symmetrical halves. Medial eminence is present an each side of median sulcus. It presents facial colliculus formed by genu (recurving fibers) of facial nerve looping around abducent nucleus. Facial colliculus lies in pons (i.e. in pontine pa of floor). Hypoglossal triangle overlying hypoglossal nucleus and vagal triangle overlying dorsal nucleus of vagus. Both of these triangle lie in the medulla (medullary pa of floor). Vestibular area overlies vestibular nuclei, paly in pons and paly in medulla. Sulcus coeruleus, a bluish area due to presence of pigmented neurons containing substantia ferruginea. Superior and inferior ea.