Cranium Flashcards
How many bones make up the skull
28
What is the difference between neurocranium and viscerocranium
Neurocranium- surrounding the brain
Viscerocranium- facial bones
What makes up the cranium
Neurocranium and viscerocranium
What are the 6 midline bones
Occipital Frontal Mandible Sphenoid Ethmoid Vomer
What are the 11 bilateral pairs of bones
Parietal Temporal Zygomatic Maxilla Nasal Palatine Lacrimal Inferior nasal concha
Dome shape roof of neurocranium
Calvaria
Floor of neurocranium
Cranial base
Majority of bones in the calvaria are fused via fibrous joints
Sutures
What separates the parietal and temporal bones
Squamous suture
What is a coronal suture
Separates the frontal and parietal bones
What is the lambdoid suture
Separates the parietal and temporal bones from the occipital bone
What is the sagittal suture
Separates the parietal bones
What is the pterion
The connection of the frontal, parietal, temporal, and sphenoid
What injury can happen to the pterion
Extradural hematoma because of bleeding to the middle meningeal artery
What are the branches to come to the middle meningeal artery
External carotid a to maxillary a to middle meningeal a
What are the parts of the ethmoid bone
Superior, inferior, middle nasal concha
What are the functions of the superior, middle and inferior concha
Covered with mucosa
Increase vascular and mucosal surface area
Warm and moistens air
What is the crista galli
Attachment point for falx cerebri
What is the cribriform plate
Tiny Formina that transmit the olfactory n from the nasal cavities to the olfactory bulbs of the brain
What is in the carotid canal
Internal carotid artery
What is in the inner ear
Cochlea and semicircular canals
What is in the middle ear
Malleus, incus, stapes
What is the epidural space of the spinal cord
True space
Contains fat and internal vertebral venous plexus
What is the dura mater of the spinal cord
Tough mother
Outermost meningeal layer
What is the subdural space of the spinal cord
Potential space
Between dura mater and arachnoid mater
What is the arachnoid mater of the spinal cord
Spider mother
Thin, delicate, a vascular
Adhered to dura mater
What is the subarachnoid space of the spinal cord
True space
Filled with CSF
Thin space accessed during lumbar puncture
What is the Pia mater of the spinal cord
Tender mother
Adhered to spinal cord
What is the epidural space of the brain
Potential space
No fat or venous plexus
What is the dura mater of the brain
Two layers
1. Periosteal layer
2. Meningeal layer- continuous with cord dura
Tightly adhered to skull
What is the subdural space of the brain
Potential space
What is the arachnoid mater of the brain
Loosely attached to dura
Contains arachnoid granulations
What is the subarachnoid space in the brain
True space
Contains CSF
Contains cerebral arteries and veins
What is the pia mater of the brain
Adhered to the brain
What is an epidural hematoma
Due to trauma Between periosteal layer of dura and bone Atrial bleed- middle meningeal a Does not cross suture line Bi-convex shape
What is a subdural hematoma
Trauma Between meningeal layer of dura and arachnoid Tears of cerebral or bridging veins May cross suture lines Crescent shaped
What is a subarachnoid hematoma
Deep to arachnoid mater
CSF and blood vessels
Ruptured aneurysm
What is an intracerebral hemorrhage
Due to trauma or hypertension
Accumulation of blood inside the brain
Rupture of blood vessels
Separates two hemispheres of cerebrum
Vertical projection
Falx cerebri
Separates two hemispheres of cerebellum
Vertical projection
Falx cerebelli
Separates cerebrum from cerebellum
Horizontal projection
Tentorium cerebelli
Covers pituitary gland
Horizontal projection
Diaphragma sellae
What is the innervation of the anterior cranial fossa
Meningeal branches of V1- ophthalmic
What is the innervation for the middle cranial fossa
Medial: meningeal branches of V2- maxillary
Lateral: meningeal branches of V3- mandibular
What is the innervation for the posterior cranial fossa
Vagus n
C1-3 cervical n
What is the blood supply for the dura
Middle meningeal a
What is the dura venous sinuses
Major venous drainage system of head
Between periosteal and meningeal layers
Lack valves
Drain to internal jugular veins in jugular formina
What drains to the dural venous sinuses
Diploic veins Emissary veins Cerebral v Bridging v Arachnoid granulations
Drain flat bones of calvarium
Diploic v
Connect extracranial v with intracranial dural sinuses
Emissary v
Drain the brain parenchyma
Subarachnoid space
Pierce the meninges and drain Into cranial venous sinuses
Cerebral v
Drain cerebrum and cerebellum
Cross subarachnoid and subdural spaces
Bridging v
Drain CSF from subarachnoid space into dural sinuses
Arachnoid granulations
What is the superior sagittal sinus and where does it receive blood from
Superior border of falx cerebri
Superior cerebral, Diploic v, and emissary v and CSF
What is the inferior sagittal sinus and where does it receive blood from
Inferior margin of falx cerebri
Cerebral v and v from falx cerebri
What is the great cerebral v and where does it receive blood from
Joined inferior sagittal sinus to form straight sinus
Superior cerebellar v, v from falx cerebri, drains deep areas of cerebral hemispheres
What is the straight sinus and where does it receive blood from
Junction of falx cerebri and tentorium cerebelli
Inferior sagittal sinus, great cerebral v, posterior cerebral v, superior cerebellar v, v from falx cerebri
What is the occipital sinus and where does it receive blood from
Falx cerebelli against occipital bone
Vertebral plexus of v
What is the confluence of sinuses and where does it receive blood from
Dilated space at the internal occipital protuberance
Superior sagittal, straight and occipital sinuses
What is the transverse sinus and where does it receive blood from
Horizontal extensions from confluence along posterior and lateral tentorium cerebelli
Confluenceof sinuses, superior sagittal, straight, superior petrosal, inferior cerebral, cerebellar, diploic, and emissary v
What is the sigmoid sinus and where does it receive blood from
Continuation of transverse sinus to internal jugular v
Transverse sinus, cerebellar, diploic, emissary v
What is the superior and inferior petrosal sinus and where does it receive blood from
Petrous part of temporal bone
Cavernous sinus, cerebellar and cerebral v
What is the cavernous sinus and where does it receive blood from
Lateral aspect of body of sphenoid
Cerebral ophthalmic v, deep veins of face, sphenoparietal sinus, emissary v
What passes through the cavernous sinus
Oculamotor n CN3 Throchlear n CN4 Ophthalmic n V1 Maxillary n CN V2 Internal Carotid a Abducent n CN 6
What is a cavernous sinus thrombosis
Rare
From: sinus infections, nasal boils, dental infections
Staphylococcus aureus
Symptoms: fever, headache, peri orbital swelling and pain
Where is CSF produced and by what
In the ventricles by choroid plexus
What is hydrocephalus
Overproduction CSF
Obstruction of CSF flow from ventricles
(Most common cerebral aqueduct)
Inability of arachnoid granulations to absorb CSF
What is most common of hydrocephalus in adults
Interruption of CSF absorption
Blood enters subarachnoid space, passes over the brain, blocks the absorption
Catheter must be placed to relieve pressure
What is most common of hydrocephalus in children
Size of dimensions of ventricle increases = brain enlarges
The sutures are not closed so head expands
VP Shunt is placed
Can neurons or mitochondria be replaced in the brain
mitchondria
what is the anterior blood supply of the brain
internal carotid artery
- ophthalmic a
- anterior cerebral a
- middle cerebral a
- posterior communicating a
what is the posterior blood supply of the brain
vertebral-basilar a
- posterior inferior cerebellar a
- basilar a
- anterior inferior cerebellar a
- superior cerebellar a
- posterior cerebellar a
- other vertebral a
what nerve is compressed between the SCA and PCA
CN III oculomotor
what are the arteries for circle of willis
internal carotid a (2)
anterior cerebral a (2)
posterior cerebral a (2) off the basilar a
anterior (1) and posterior communicating a (2)
what nerve exits the cribriform plate
CN 1 olefactory
what nerve exits the the optic canal
CN II optic
what sits in the sella turcica/hypophyseal fossa
pituitary gland
what nerves are in the superior orbital fissure
CN V1- ophthalmic, CN III oculomotor, CN IV trochlear, CN VI abducens
what nerve is in the foramen rotundum
CN V2- maxillary
what is in the foramen ovale
CN V3- mandibular
what is in the foramen lacerum
internal carotid a
what is in the foramen spinosum
middle meningeal a
what nerves are in the internal acoustic meatus
CN VII facial, CN VIII vestibulochlear
what nerves are in the jugular foramen
CN IX glossopharyngeal, CN X vagus, CN XI accessory
what nerve is in the hypoglossal canal
CN XII hypoglossal
what is in the foramen magnum
spinal cord
what is the strongest and weakest point of the cranium
strongest- petrous
weakest- pterion