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Unformatted text preview: 1 Chapter 7 - Pages 865 to 876 Cranial Meninges and Interior of Skull Cranial meninges are the membranous coverings of the brain that lie immediately internal to the cranium 2. composed of three membranous connective tissue layers Functions 1. protect the brain 2. form the supporting framework for the arteries, veins and venous sinuses 3. enclose a Fuid - ¡lled cavity, the subarachnoid space which is vital to the normal function of the brain The cranial meninges composed of three membranous connective tissue layers 1. dura mater ( dura ) tough, thick, external ¡brous layer 2. arachnoid mater ( arachnoid ) thin, intermediate layer 3. pia mater ( pia ) delicate, internal vasculated layer Leptomeninx are the intermediate and internal ( arachnoid and pia ) continuous membranes Subarachnoid ( leptomeningeal ) space 1. separates the arachnoid from the pia ¡lled by the cerebrospinal Fuid 2. the Fuid - ¡lled space help to maintain the balance of extracellular Fuid in the brain Cerebrospinal ¡uid ( CSF ) 1. is a clear liquid similar to blood in constitution 2. it provides nutrients but has less protein and a different ion concentration 3. CS¢ is formed by the choroid plexuses of the fourth ventricle of the brain 4. leaves the ventricular system and enters the subarachnoid space, where it cushions and nourishes the brain Dura mater 1. thick, dense, bilaminar membrane, also called the pachymeninx 2. it is adherent to the internal table of the calvaria 3. external periosteal layer is formed by the perisoteum covering the internal surface of the calvaria 4. internal meningeal layer , a strong ¡brous membrane, that is continuous at the foramen magnum with the spinal duramater covering the spinal cord Dural in¡odings or re¡ections 1. the internal meningeal layer is a supporting layer forms infoldings ( reFections ) 2. it divides the cranial cavity into compartments, forming partial partitions 3. providing support for the other parts of the brain Dural Infoldings 1. falx cerebrai ( cerebral falx ) 2. tentorium cerebelli ( cerebellar tentorium ) 3. falx cerebelli ( cerebellar falx ) 4. diaphragma sellae ( sellar diaphragm ) Falx cerebri 1. is the largest dural infolding, sickle shaped, lies in the longitudinal cerebral ¡ssure 2. separates the right and left cerebral hemispheres 2 Attachment of the falx cerebri Anteriorly to the frontal crest of the frontal bone and crista galli of the ethmoid bone Posteriorly to the internal occipital protuberance and continues with the tentorium cerebelli Tentorium cerebelli 1. is the second largest dural infolding, is a wide cresentic septum 2. separates the occipital lobes of the cerebrum from the cerebellum Attachments of the tentorium cerebelli 1. to the clinoid process of the sphenoid bone ( rostrally ) 2. petrous part of the temporal bone ( rostrolaterally ) 3. internal surface of the occipital bone ( posterolaterally ) 4. part of the parietal bone ( posterolaterally ) Tentorial notch is the gap in the concave free anteromedial border, through which the brain stem...
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- Winter '11
- oculomotor nerve, Veins of the head and neck, Cavernous sinus