1 - THE BRAIN AND CEREBRAL VENTRICLES

Abstract

Publisher Summary This chapter describes the brain and cerebral ventricles. There are four intercommunicating cerebral ventricles, two lateral, and a third and fourth, which lie in the median plane. They are lined by ciliated epithelium and contain cerebrospinal fluid. The choroid plexus invaginates the ependyma into the body of the lateral ventricle on its medial wall and extends forward as far as the interventricular foramen, where it becomes continuous with the choroid plexus of the other side. Posteriorly, it is carried around into the posterior and inferior horns. The cerebrospinal fluid is produced by the choroid plexus, mainly in the lateral ventricles. It drains into the fourth ventricle and passes through the medial and lateral foramen into the subarachnoid space. The lateral ventricles are irregular cavities in the lower medial parts of the cerebral hemispheres, one on each side of the median plane. They are separated by a median vertical septum—the septum pellucidum. The lateral ventricles communicate indirectly with the third ventricle through the interventricular foramen (foramen of Monro). Each ventricle consists of a central part and three horns: (1) anterior, (2) posterior, and (3) inferior. The third ventricle is a median cleft between the two thalami. Posteriorly, it communicates with the fourth ventricle through the aqueduct and anteriorly with the lateral ventricles through the interventricular foramen. The fourth ventricle is a lozenge-shaped space in front of the cerebellum. It is continuous inferiorly with the central canal of the medulla oblongata.