Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== FOURTH VENTRICLE ====== {{ :maps:fourth_ventricle.svg |}} Fourth Ventricle * floor * rhomboid fossa (diamond shaped) * formed by * posterior (dorsal surface) * lower or closed part of pons * open or upper part of medulla oblongata * structural layers * ependyma * thin layer of neuroglia * beneath ependyma * layer of grey matter forming various nuclei * parts * upper triangular part * dorsal surface of pons * lower triangular part * dorsal surface of medulla * intermediate part * junction of pons and medulla * prolonged laterally over inferior cerebellar peduncle * as floor of lateral recess * marked by transverse fibres of striae medullaris * arcuate nucleus to cerebellum * features * dorsal median sulcus * sulcus limitans * divides each half * median eminence * wider above * narrow below * facial colliculus * deep to it is genu of facial nerve * formed by looping around abducent nucleus * lateral vestibular area * depression at cranial end * superior fovea * depression at caudal end * inferior fovea * sulcus limitans runs obliquely * two triangle * hypoglossal triangle * vagal triangle * upper part is locus ceruleus * bluish in colour * pigmented neurons * substantia ferruginea * help in paradoxical sleep * rich in noradrenaline * lowest part resembles tip of writing pen * calamus scriptorius * between vagal triangle and gracile tubercle * area postrema * function as chemoreceptor * ependymal thickening * funiculus separans * separates both * tela choroidea * double layer of piamater * covered by secretory ependyma * forms choroid plexus * lateral boundaries * each side bounded by * inferolaterally by * tubercles * gracile tubercle * cuneate tubercle * superolaterally by * superior cerebellar peduncle * roof * parts * superior * formed by superior cerebellar peduncle and * superior medullary velum * fills the gap between superior cerebellar peduncle * covered on dorsal syrface by lingula of superior vermiss (cerebellum) * inferior * very thin * devoid of nervous tissue * tela choroidea of fourth ventricle covers it posteriorly * caudally median aperture * communicate with subarachnoid space in * cerebello medullary cistern * inferior medullar velum * forms a part of roof in region of nodule of cerebellum * superior to inferior medullar velum * tela choroidea * reaches floor * marked by a ridge tenia * opening in roof * median aperture or foramen of magendie * situated caudal to nodule * communication between csf and subarachnoid space * foramen of luschka * present on lateral recess * subarachnoid space * communication * inferiorly with central canal * superiorly with cerebral aqueduct en/fourth_ventricle.txt Last modified: 2023/06/14 05:07by 127.0.0.1