Brain bones/ Meninges and CSF Flashcards
Skull
Facial Bones + cranial vault
28 bones
Cranial bones
8 bones, 7 visible
the bones are named after the regions of the brain that they cover
Frontal = 1 - forehead
Parietal = 2 - one on each side
Temporal = 2 - behind the ears
Occipital = 1 - the bump on the back of the skull
Sphenoid = 1 - butterfly shape that goes through the head we see either side of it on the sides of the head.
Sutures
the fibrous joints between the bones of the cranium that dont allow any movement
Coronal suture
frontal and parietal bones
Lambdoidal suture
Occipital and parietal bones
Squamous suture
temporal and parietal bones
Fontanelles
the gaps between sutures/ bones in new borns. they allow the brain and the skull to grow. premature closure of sutures can block brain growth.
Facial Skeleton
7 external bones and 7 internal bones
Zygomatic = 2 - cheek bones
Maxillary = 2 - upper part of jaw, little bit of fusing under the upper lip. around the nose and apples of cheeks.
Mandible = 1 - jaw
Nasal = 2 - in-between the eyes above the nose.
Meninges
Protective covering for the brain. like a membrane between the skull and the brain.
made of 3 layers
Dura and Pia mater
Arachnoid
Dura Mater
outer most layer dense and fibrous - tough contains 2 layers outer layer forms the venous sinuses inner layer forms the dura reflections
Dura reflections
formed from the inner layer of the dura mater
separates the major divisons of the brain
3 of them
inward extensions of the dura mater
Flax Cerebri
separates the central hemispheres, median plane
Flax Cerebelli
separates cerebellar hemispheres, median plane
Tentorium Cerebelli
separates the cerebrum from the cerebellum, horizontal plane
Venous Sinus
Triangle shape formed between the outer and inner layers of the dura mater venous drainage from the brain cerebrospinal fluid pumped into here goes down the length of the brain
Arachnoid
spider like
layer beneath the dura mater
does not extend into the sulci (valleys of the brain)
sheet raised up on legs which creates a space and in this space is where blood vessels and CSF can circulate. this is called the subarachnoid space.
Subarachnoid space
area between pia mater and arachnoid
filled with cerebrospinal fluid (CSF)
Provides cushioning for the brain
Arachnoid granulations (villi)
extensions of the arachnoid that go through the dura mater from the subarachnoid space into the venous sinus
pumps ‘old’ CSF into the venous sinus
Pia Mater
delicate material
blood vessels and subarachnoid space sit on top of the pia mater
adheres to brain and follows the crevices/ valleys of the brain (gyri and sulci)
Meninges of the spinal cord
has the same 3 layers as the brain does. covers everything around the spinal cord/ cavity including spinal nerves and ganglions
The Ventricular System
network of interconnected spaces within the brain
filled with CSF
Choroid Plexus
where CSF is produced
lines the ventricles of the brain
Circulation of CSF
starts in the lateral ventricle (which extends through multiple areas of the brain)
next goes to the 3rd ventricle then to the cerebral aqueduct the to the 4th ventricle then to the subarachnoid space where it is pumped into the venous sinus through the arachnoid villi or it goes down the central canal of the spinal cord.
it is then samples to see if meningitis is present
Cerebrospinal fluid
CSF
Bathes and cushions the brain
circulates through the ventricles and the subarachnoid space and the spinal cord
Hydrocephalus
when the ventricular system goes wrong
enlarged ventricles and a blocked aquaduct
caused by abnormal circulation of CSF in ventricles
leads to increased inter-cranial pressure inside the skull
progressive enlargement of the head
leads to convulsions, tunnel vision, mental disability
