MEMBRANES AND VENTRICLES OF THE BRAIN

1/12/82, 11 Jan 00, 15 Jan 03, 14 Jan 04, 30Jan08

 S&M p 315, Martini’s 4^th: 448-453, 6^th: p 467, 7^th: 453-459

MENINGES (meninx: = membrane) three layers covering CNS: p456

DURA MATER (hard mother): double layered around brain,

            outer:  periosteum, attached to cranial bones

            inner:  continuous with dura mater of spinal cord.

Folds:              falx cerebri                 strong septum between hemispheres, attaches to crista galli

                        falx cerebelli               between cerebellar hemispheres also

                        tentorium cerebelli     between cerebrum and cerebellum

ARACHNOID MENINX     (spider, cobweb-like) middle layer of three, adheres closely to inner surface of dura.

sub-arachnoid space, connected with pia mater by cobweb-like strands, filled with CSF.

PIA MATER             (soft mother) delicate vascular, areolar connective, participates with the arachnoid to form choroid plexus.

VENTRICULAR SYSTEM, p 454

System of ventricles is a continuous fluid filled system:

            choroid plexus (p 457) (braid) folds in pia mater with network of capillaries produce:

Cerebrospinal fluid (CSF), bathes organs of central nervous system

            arachnoid villi (p457) resorb CSF.              Formed by projections of arachnoid meninx into dural venus sinuses

Illustrate Superior sagittal sinus with membranes, arachnoid villi.

Lateral ventricle:     within each cerebral hemisphere, possess horns: superior, inferior, posterior

                                    two separated by thin septum pellucidum

                                    Connects with the third ventricle by foramen of Monro

Third Ventricle:       narrow, within diencephalon, thalamus forms walls.

                                    cerebral aqueduct communicates with the fourth ventricle

Fourth ventricle:      within the hind brain, ventral to cerebellum has three openings:

                                                two foramina of Luschka (lateral aperture)

                                                one foramen of Magendie (medial aperture)

These lead to space surrounding brain, and subarachnoid space of spinal cord

Central canal of spinal cord continuous with fourth ventricle.