Ventricles and the Cerebrospinal Fluid

6.1

Ventricular Anatomy

The lateral ventricles are C-shaped, reflecting their association with the developing telencephalon as it sweeps upward, back, and then down and forward as the temporal lobe. The position of the lateral ventricles in relation to the head and body of the caudate nucleus is an important radiological landmark in a variety of conditions, such as hydrocephalus, caudate atrophy in Huntington’s disease, and shifting of the midline with a tumor. Cerebrospinal fluid (CSF) flows through the interventricular foramen of Monro into the narrow third ventricle, then into the cerebral aqueduct and the fourth ventricle. Blockage of flow in the aqueduct can precipitate internal hydrocephalus, with swelling of the ventricles rostral to the site of blockage. The escape sites where CSF can flow into expanded regions of the subarachnoid space called cisterns are the medial foramen of Magendie and the lateral foramina of Luschka. These foramina are additional sites where blockage of CSF flow can occur. The choroid plexus, extending into the ventricles, produces the CSF. See Videos 6.1 and 6.2.

6.2

Ventricular Anatomy in Coronal Forebrain Section

A coronal section through the diencephalon shows the bodies of the lateral ventricles, the narrow interventricular foramina of Munro, and the midline third ventricle. The flow of CSF is from the lateral ventricles into the third ventricle. The choroid plexus protrudes into both the lateral and third ventricles and produces CSF. The temporal (inferior) pole of the lateral ventricle and its associated choroid plexus are shown in the temporal lobe.

6.3