Anatomy – (Meninges, Ventricles, Sinuses)
MENINGES:
Bone structures:
-->Cranium (Neurocranium):
-->Cerebrum - cerebellum – truncus cerebri (Beyin, beyincik, beyin sapı)
-->Columna vertebralis:
-->Medulla Spinalis (omurilik)
--> Meninges:
-->Dura mater
=
Pachymeninx
-->Arachnoidea mater
Leptomeninx
-->Pia mater
--> Dura mater: outermost and strongest membrane, no strecth fibrous con. t.
--> Arachnoidea mater: the spider web-like
between the other two membranes
--> Pia mater: innermost membrane, attached to
brain / sinal cord tissue
1) DURA MATER:
It has two layers: are conjoined except “sinus venosus” (filled with venous blood)
-->Lamina externa (periosteal layer)
-->Lamina interna (meningeal layer)
**
2 parts:
-->Dura mater cranialis
-->Dura mater spinalis
A) Dura Mater Cranialis: surrounds the brain
-->Lamina externa (periosteal layer) is the periosteum, covers inner surface of
skull bones, loosely attached
--> also called dura periostalis
-->Lamina interna (meningeal layer)
--> also called dura encephali
**Lamina interna:
*main dura mater layer, beyin dokularını asıl o sarıyor
* continues as dura mater spinalis around the Medulla Spinalis
It forms the epineurium of the cranial nerves outside the cranium,
**sinirlerin geçeceği tüp/kılıf
It sends some extensions between CNS structures; beyin dokuları arasına gönderdiği uzantılar
-->falx cerebri
-->falx cerebelli
-->tentorium cerebelli
-->diaphragma sellae
a) Falx cerebri:
--> It lies between the cerebral hemispheres. (beyin yarı küreleri arasına giren uzantı)
--> It is in the fissura longitudinalis cerebri.
b) Falx cerebelli:
--> small, sickle-shaped,
--> Its free anterior margin enters between
the cerebellar hemispheres.
c) Tentorium cerebelli: beyinciğin örtüsü
-->It overlies the posterior fossa cranii
--> It is between the occipital lobe
and the cerebellum.
--> İt’s anterior border: incisura tentorii
d) Diaphragma sellae:
--> It covers the sellae turcica on the upper
surface of the corpus of the sphenoid bone.
**Arter ve Venleri sonra tekrar anlatacak.
Tentorium cerebelli ve falx cerebri birleşim
yerinde “sinus rectus” bulunuyor.
B) Dura Mater Spinalis:
It closes at the S2 vertebral level and joins the
structure of the filum terminale.
It ends by fusing to the periosteum and bone tissue of
the 2nd coccygeal vertebra.
Spatium epidurale [peridurale] :
• In the space between the dura mater spinalis
and the periosteum;
** the plexus venosus vertebralis internus and
loose areolar tissue are located.
The vein plexus is the counterpart of the sinus
venosus in the dura mater cranialis.
Kemik doku
Vein plexus
Spatium epidurale
Dura mater
2) ARACHNOİDEA MATER:
*not permeable
2 parts:
-->Arachnoidea mater cranialis
-->Arachnoidea mater spinalis
A) Arachnoidea Mater Cranialis (Encephali) :
-->It enters only the large slits / crevices / fissures where the falx cerebri, falx cerebelli and
tentorium cerebelli are located.
• It does not enter the sulcuses / grooves on the brain. (dura materle aynı yerleri örtüyor)**
**Beynin bütün bu
kıvrımlarını örten
pia materdir
Spatium
subdurale is
located
between the
dura mater and
arachnoidea
mater
Dura mater
Arachnoidea mater
Pia mater
Sulcus cerebri
Arachnoidea mater sends extensions called "villi arachnoidea" into "lacuna vasorum"
• These extensions cluster together to form the cauliflower-like "Granulationes arachnoidea
(pacchioni corpuscle)"
It allows the passage of CSF to the venous system. ***
(spider webs= trabeculae arachnoidea)
B) Arachnoidea Mater Spinalis:
It ends at the level of the S2 vertebra
Spatium Subarachnoidea
The space between arachnoidea mater and the
pia mater is called "spatium subarachnoidea"
• This space contains CSF !!!
"spatium subarachnoidea" shows enlargement between L1 – S2
vertebrae
• enlargement is called Cisterna Lumbalis
• Spinal anesthesia is applied to this space between L3-L4.
*CSF --> dura mater sinüse dökülür --> venöz kan dolaşımına katılır
(sürekli salınıp emilir)
3) PIA MATER:
-->Lamina externa (epipial layer)
--> Lamina interna (intima pia)
2 parts:
--> Pia mater cranialis
--> Pia mater spinalis
A) Pia Mater Cranialis:
Tela choroidea forms “plexus choroideus” (damar yumağı) → !! Produces CSF
B) Pia Mater Spinalis:
Fibers of Fissura mediana anterior condenses and forms Linea Splendens
Pia mater condenses between spinal nerve roots and forms Lig. Denticulatum
***Soru dedi
(allows medulla spinalis to maintain it’s position)
Filum terminale: It is an extension of pia mater
• It extends down from the conus medullaris (L1-2)
• It extends to coccygeal 1st or 2nd vertebra
• about 20 cm
Parts of the filum terminale;
--> filum terminale internum (pars piale)
--> filum terminale externum (pars durale)
Spatium subarachnoideum; expands in some places
and forms Cisternae subarachnoidea (boşluktaki genişlemeler)
Cisterna cerebellomedullaris posterior [magna]:
• It is between the lower surface of the cerebellum and the roof of the ventriculus quartus
Cisterna lumbalis:
• It is between L 1 – S 2 vertebra.
Contents:
• Filum terminale
• Cauda equina
VENTRICLES:
Ventriculus:
• They are in the brain (cerebrum) and brain stem (truncus cerebri)
• They contain "Cerebrospinal Fluid (CSF)"
• They are interconnected spaces
• They develop from the lumen of the tubus neuralis (canalis neuralis)
-->Ventriculus lateralis
on the right (1st ventricle) and
They are located within the cerebral
hemispheres. (beyin yarım küreleri içerisinde)
on the left (2nd ventricle)
**Foramen interventriculare (foramen of Monro): 2 holes, right and left.
CONNECTS 2 ventricles
-->Ventriculus tertius
It is in the middle of both thalamus and hypothalamus.
(3rd ventricle)
**Aqueductus mesencephali (aqueductus cerebri, aqueduct of Sylvius)
CONNECTS 2 ventricles
-->Ventriculus quartus
(cisterna cerebellomedullaris )
Spatium subarachnoideum
(4th ventricle)
It is at the back of the brain stem (truncus cerebri), in front of the cerebellum.
1) Ventriculus quartus:
• below (caudal), it continues with the canalis centralis, which lies within the Medulla Spinalis.
-->Apertura mediana ventriculi quarti (foramen of Magendie):
• It is located behind and in the middle of the 4th ventricle.
• It is single, opens into the subarachnoid space
-->Apertura lateralis ventriculi quarti (foramen of Luschka):
• double on both sides of 4th ventricle
• They open into the subarachnoid space
Plexus Choroideus:
Tela choroidea and ependymal cells form “plexus choroideus” (damar yumağı) → !! Produces CSF
**It is found in all ventricles
It is absent in cornu frontale [anterius] and cornu occipitale [posterius]. ***** Aşağıda
CSF produced mostly from ventriculus lateralis *****
2) Ventriculus lateralis: 2 lateral walls
--> Ventriculus Lateralis Dexter (1st ventricle),
--> Ventriculus Lateralis Sinister (2nd ventricle)
They are seperated from each other by the septum pellucidum located between the 2 ventricles.
It also forms the medial wall of ventriculus lateralis
Parts of the lateral ventricles:
-->Pars centralis
-->Cornu frontale [anterius]
-->Cornu occipitale [posterius]
-->Cornu temporale [inferius]
-Junction of pars centralis, cornu posterius and cornu inferious is Trigonum collaterale
**Septum pellucidum is composed of 2 layers; lamina septi pellucidi,
sometimes there is a gap between them = Cavum septi pellucidi
SINUSES
Sinus Durae Matris:
They are between the two layers of the dura
mater cranialis
Venous blood of the brain and some skull
bones, and CSF drain into these structures
-Durameter sınuses contain blood & CSF
Finally, the venous blood in the dural sinuses
pours into the v.jugularis interna
There is no valve. (klasik damar yapısında değil)
There are no muscle fibers in their walls.
1) Sinus sagittalis superior:
-->It starts near the crista galli.
It runs along the convex upper margin of the falx cerebri.
2) Sinus sagittalis inferior:
--> It extends posteriorly 2/3 posterior to the free lower border of the falx cerebri.
--> It fuses with the v.magna cerebri (vein of Galen) to form the sinus rectus.**
3) Sinus rectus:
POT Q **
--> It is formed by the union of the V.magna cerebri
özellikle vurguladı
(vein of Galen) and the sinus sagittalis inferior at
the junction of falx cerebri and tentorium cerebelli**
4) Sinus transversus:
--> They are located where the tentorium cerebelli attaches to the sulcus sinus transversus.
Dura mater yaprakları arasında oluşur.
Confluens sinuum (torcular Herophili): enlargment of sinüs sagittalis superior
The junction of
Sinus sagittalis superior
Sinus rectus
Sinus occipitalis
Sinus transversuses
5) Sinus sigmoideus:
-->It is the continuation of the sinus transversus
-->It continues as v. jugularis interna
6) Sinus occipitalis:
-->It is located where the falx cerebelli attaches to the os occipitale.
7) Sinus petrosus superior:
-->It runs along the upper edge of the Pyramis (os temporale)
--> It connects the sinus cavernosus to the sinus transversus.
8) Sinus petrosus inferior:
--> It runs along the lower edge of the Pyramis (os temporale)
-->It connects the sinus cavernosus to the v. jugularis interna.
--> It is the only dural sinus that extends outward from the skull.
9) Sinus sphenoparietalis:
-->It opens into the anterior part of the sinus cavernosus
10) Plexus Basilaris (Sinus Basilaris):
-->They connect the sinus petrosus inferior, sinus petrosus superior, and sinus cavernosus.
11) Sinus cavernosus:
POT Q
• in fossa cranii media
• on the sides of the body of the sphenoid bone
--> They are connected to each other via sinus intercavernosus anterior and sinus intercavernosus posterior
--> They are connected to V. Facialis via v.ophthalmica superior.
--> They are connected to the plexus pterygoideus by a v. emissaria passing through the foramen ovale
--> They connect to the sinus transversus via the sinus petrosus superior.
--> They are connected to V. jugularis interna by the sinus petrosus inferior
The structures passing through ;
The structures passing through the
• a. carotis interna
outer wall ;
• n.abducens
• n.oculomotorius (CN III)
It is adjacent to the hypophysis cerebri and
sinus sphenoidalis on the inside.
• n.trochlearis (CN IV)
Aleyna Çabuk
• n.ophthalmicus (CN V-ı)
• n.maxillaris (CN V-ıı)