The meninges system
Reading instructions
To get the most out of this learning tool, please read:
Bear, Mark F, Connors, Barry W., Paradiso, Michael A. Neuroscience : exploring
the brain. - 2 ed.
Chapter 7 page 163-252
Illustrations and anmimation
Meninges/meninges
Three meninges cover the brain, the dura/dura mater, the arachnoid/arachnoidea
and the pia/pia mater. The dura is the most superficial of the
meninges and is separated from the arachnoid by a latent space,
the subdural space. Between the arachnoid and the pia, the subarachnoidal
space is located containing cerebrospinal fluid and cerebral arteries.
The pia goes along with the vessels over the brains gyri and sulci.
The dura/dura mater
The dura is a fibrous tissue consisting of two layers, an outer periosteal
layer and an inner meningeal layer. The dural layers are separated
where the dural sinuses are placed. One of the dural septa, the
falx cerebri/falx cerebri, extends between the two cerebral hemispheres
whereas another dural septa, the tentorium cerebelli/tentorium
cerebelli separates the cerebellum from the occipital lobes.and
this dural septa is fused to the falx cerebri in the midline. In
the anterior margin there is an opening, the tentorial notch/incisura
tentorii where the superior brainstem, aquduct and vessels pass.
There is also a dural septa between the two cerebellar hemispheres,
the falx cerebelli. The diaphragma sellae forms an incomplete cover
over the hypophysis allowing the pituatory stalk/infundibulum.
The dura mater in the anterior and the middle cranial fossae is sensory innervated by the trigeminal nerve while the dura in the posterior fossa is supplied by the upper three cervical nerves and by branches from the vagal/nervus vagus (X) and hypoglossal /nervus hypoglossus (XII) cranial nerves.
The arachnoid/arachnoidea
The arachnoid covers the subarachnoidal space wich is filled with
cerebro spinal fluid (CSF). It does not go into sulci or fissures
except to go along with the falx and the tentorium. Arachnoid granulations/granulationes
arachnoidales are built up by microscopic villi that appear as
berry-like aggregations protruding into the superior sagittal sinus
and adjacent venous lacunae and in other sinuses and large veins.
The arachnoid granulations are the locations of the absorbtion
of CSF. The subarachnoidal space form widened spaces called cisterns
and the cisterna magna is the biggest lying between the medulla
and the cerebellum and is continuous with the spinal subarachnoidal
space.
Pia/pia mater
The pia is a very delicate membrane that covers the surface of the
brain and extends into fissures and over sulci.