Lecture 2- Meninges, CSF, Ventricular system, Cerebral hemispheres Flashcards
3 brain coverings
Dura mata - subdural spaces (increased arteries) Arachnoid mata - subarachnoid space (CSF and increased veins) Pia mata - adheres directly onto brain
Dura mata layers
Fibrous endosteal
Meningeal
- dural venous sinuses in between some sites
Dural reflections
Falx cerebri (partial separation of cerebral
hemispheres)
Falx cerebelli (partial separation of cerebellar
hemispheres)
Tentorium cerebelli
Diaphragm sellae
Blood supply of dura
Ethmoidal artery (ant + post) Internal carotid artery Middle meningeal artery Maxillary artery Ascending pharyngeal artery Occipital artery Vertebral artery
Nerve supply of dura mata
Meningeal branches of
- Maxillary
- Mandibular
- Upper cervical nerves
Arachnoid mata
Thin, vascular membrane
Attaches to dura by several layers of flattened cells
Conforms to general shape of brain but does not fit into every sulcus
Separated from Pia by arachnoid trabeculae and subarachnoid space
Specialisations of arachnoid mata
Trabeculae
Villi
Barrier
Arachnoid trabeculae
Strands of collagenous connective tissue from arachnoid to pia
Arachnoid villi
For reabsorption of CSF
Outgrowths of arachnoid projecting through the dura into the sinuses
Form granulations with age
Arachnoid barrier
Cells of outermost arachnoid layer have tight junctions
Prevents spread of microbes from the dura into the subarachnoid space so that they don’t reach the brain
Pia mata
2-3 cells thick
Attaches to end feet of arachnoid trabeculae, helps to keep arachnoid space open
Closely follows all sulci and gyri of brain
Penetrated by arteries and veins when they enter or leave the brain substance (perivascular space)
Spinal meninges
Devoid of fibrous layer (endosteal) of dura which ends at margin of foramen magnum
Arachnoid mata stays relatively the same
Pia mata forms 21 pairs of denticulate ligaments and is thickened anteriorly to give a shiny appearance in the midline (linea splendens and filum terminale)
Ventricular system
Lateral ventricles (cerebrum) via intraventricular foramen to 3rd ventricle (diencephalon) via cerebral aqueduct to 4th ventricle (pons/medulla)
Parts of lateral ventricle
Anterior (frontal
Body
Posterior (occipital)
Inferior (temporal)
Walls of 3rd ventricle
Anterior wall Posterior wall Sides= Thalamus Roof Floor