Cranial Vault Flashcards
What are the 3 bones of the foor of the cranium?
- Frontal (ant)
- Parietal (middle)
- Occipital (post)
Suture between the frontal and parietal bones
Coronal Suture
Suture between parietal bones
Saggital Suture
Suture between the parietal and occipital bones
Lambda
junction of the coronal and sagittal sutures
Bregma
junction of the lambdoid and sagittal sutures meet
Lambda
In the frontal bone, a groove that runs ant to post. Attaches.
Groove for the superior sagittal sinus
Pitting on the parietal bones
Granular foveolae
Grooves left behind by the middle meningial artery on the parietal bone since it is embedded on it.
Grooves for the middle meningeal artery
What aretery prominatley supplys blood to the dura?
Middle meningial artery
What are the 3 bones in the anterior cranial fossa?
- Frontal bone – anterior and lateral directions
- Ethmoid bone – in the midline
- Sphenoid bone – midline (body) and lateral (lesser wing) – posterior
frontal (pink), Ethmoid (green), Sphenoid (yellow)
Thin part of frontal bone by the eye
Orbital Plate
What part of ethmoid bone (green)?
- At the junction of the frontal bone and the ethmoid bone
- Emissary vein from nose to superior sagittal sinus
Foramen Cecum
What part of ethmoid bone (green)?
Lateral on the ethmoid bone, **Have little holes, Location where olfactory bulbs of CN1 sit **and travel into the nasal cavity.
Alow olfactory neuron to travel to the nose.
Cribifrom Plate of Ethmoid Bone
What part of ethmoid bone (green)?
Allow passage of ant and posterior ethmodial vein and nerve.
(anterior is larger)
Anterior & Posterior ethmoidal foramen
What part of ethmoid bone (green)?
Triangular fin like structure in the center, attachment point for dura.
Crista galli
What part of sphenoid bone (yellow)? ant.
In anterior, lateral smaller wings
Lesser wings
What part of sphenoid bone (yellow)? Ant.
Off of the lesser wings, centered more anterior
Body of sphenoid
What part of sphenoud bone (yellow)? ant.
Comes off going posterior to the lesser wings
Anterior Clinoid Process
What are the 2 bones in the middle cranial fossa?
- Sphenoid – greater wing
- Temporal
What part of sphenoid bone (yellow)? middle
In the center of the sphenoid bone, in between greater wings.
The cowboy Saddel
Sella turcica
What part of sella turcica (spehnoid bone)?
Right in the center of sella turnica. Where the pituitary gland sits.
Pitutatry glad is the rider on the saddle.
Hypophyseal fossa
What part of sella turcica (spehnoid bone)?
On the posterior aspect, has a posterior clinoid process on either side
Dorsum Sellae
What part of sella turcica (spehnoid bone)?
Posterior, on either side of the dosum sellae
Posterior clinoid process
What part of sella turcica (spehnoid bone)?
Located anterior,
Helps form part of chiasamatic groove where optic nerve comes through, and criss crosses into the canal
Tuberculum Sellae
What part of sella turcica (spehnoid bone)?
Groove where ** optic nerve comes through and criss crosses into the canal**
Chiasmatic groove
Chiasmic= cross over.
Sphenoid fissures and foramina
Where is the optic canal?
If positioned at the sellae turcia, anterior to this.
Sphenoid fissures and foramina
What goes throught the optic canal?
- Optic Nerve CN2
- Optic/opthalmic Artery
Sphenoid fissures and foramina
Where does the superior orbital fissure sit?
Sits lateral to the optic canal LOTS goes through here.
Sphenoid fissures and foramina
What 5 goes through the superior orbital fissure?
- Occulomotor CN3
- Trochlear CN4
- Opthalmic CN5V1
- Abducent CN6
- Superior opthalmic Veins
Sphenoid fissures and foramina
Where is the foramen Rotundum?
The wide opening. Located laterally anterior and below superior orbical fissure
Sphenoid fissures and foramina
What goes through the foramen rotundum?
Maxillary nerve CN5V2
Sphenoid fissures and foramina
Where is the foramen ovale?
Located more posteriro lateral on he sphenoid. Larger.
Sphenoid fissures and foramina
What goes through the foramen ovale?
- Mandibular CN5V3
- Somtimes acc. middle meningial artery
Sphenoid fissures and foramina
Where is the foramen spinosum located?
Even more posterior lateral from center. Farthest out
Sphenoid fissures and foramina
What goes through the Foramen spinosum
- Middle meningeal artery and associated vein
- Recurrent meningeal ln. (CN V3)
Sphenoid fissures and foramina
Where is the foramen lacerum located?
Right posterior lateral to the dorsum sellae.
Sphenoid fissures and foramina
What goes through the foramen lacerum?
- Cartilaginous plug
- Meningeal br. of ascending pharyngeal a.
somtimes…
What are the
What are the 6 forament and fissure of the sphenoid bone?
- Optic canal
- Superior orbital fissure
- Foramen rotundum
- Foramen ovale
- Foramen Spinosum
- Foramen lacerum
Temporal bone fissures and foramina
What are the 3 Foramen and fissure in the temporal bone?
- Groove and hiatus for greater petrosal nevre
- Groove and hiatus for lesser petrossal nerve
- Tegmen Tympani
Temporal bone fissures and foramina
What is the petrirfied and very hard portion of the temporal bone called?
Middle and inner ear (protected well)
Petrous part
Temporal bone fissures and foramina
- Greater petrosal n. (CN VII),
- petrosal branch of middle meningeal a.
Groove and Hiatus for the greater petrosal nerve
Temporal bone fissures and foramina
- Lesser petrosal n. (branch from tympanic plexus originally from CN IX – glossopharyngeal)
Groove and Hiatus for the lesser petrosal nerve
Closer to foramen ovale and spinosum
Temporal bone fissures and foramina
Space below the tympanic membrane that leads to the inner ear.
Tegmen tympani
What are the 4 bones in the posterior cranial fossa?
- Temporal (majority)
- Occipital (good amount)
- Sphenoid (small contribution laterally)
- Parietal (small contribution anteriorly)
Structures and foramina of Posterior Fossa
What is the slide posterior from sphenoid? Leads to foramen magnum
Clivus
Structures and foramina of Posterior Fossa
Describe Foramen magnum?
In the occipital bone, LARGE opening. Lots passes through
Structures and foramina of Posterior Fossa
What passes through the foramen magnum
- Spinal cord
- Spinal roots of CN XI after it has exited and come back up through and exit later
- Vertebral aa.
- Anterior and posterior spinal aa.
- Meninges
- Veins
Structures and foramina of Posterior Fossa
Where is the external acoustic meatus?
Anterior and superior to the jugular foramen on the temporal bone
Structures and foramina of Posterior Fossa
What goes through the internal acoustic meatus
- Facial Nere CN7
- Vestibulochoclear CN8
- Internal labyrinthine artery
Structures and foramina of Posterior Fossa
THe 2nd largest opening in the the occipital bone, lateral anterior to the foramen magnum
Jugular foramen
Structures and foramina of Posterior Fossa
What goes through the jugular foramen?
- Glossopharyngeal CN9
- Vagus CN10
- Acessory CN11
- Inferiro petrosal sinus + sigmoid sinus forming the internal jugular vein
Structures and foramina of Posterior Fossa
What happens if you have an aneurysm or blockage of the Internal labyrinthine artery?
Loose all inner ear function
Structures and foramina of Posterior Fossa
What 2 sinuses for the internal jugular vein?
Inferior petrosal sinus + Sigmoid sinus
Structures and foramina of Posterior Fossa
Where is the hypoglossal canal located?
Located more medial that the juglar, close to foramen magnum.
Structures and foramina of Posterior Fossa
What travels through the hypoglossal canal?
- Hypoglossal CN12
- Menegial branch of ascending pharygeal artery
2 layers, most external layer of the meninges
Dura Mater
Explain the 2 layers of the dura mater
- Periosteal layer; next to the skull
- Meningeal layer ; next to arachnoid mater
In certain layers of the dura mater the 2 layers (periosteal and meningeal later) wil split open this results in?
Free venous blood flow between these 2 layers with no valves
Contains CFS and blood vessles (A/V) for the brain. Under the dura mater
Arachnoid matter.
Can be pulled off, loosley associated
Below the arachnoud mater, Closely invests on the surface of the brain. Enters grooves and fissures on the surface of the brain
Cannot be seperated from brain ina disection
Pia Mater
Explain Extradural space
Potential space between the dura and bone
What happens if you rupture the middle meningial artery in the extradural space?
Blood can pool, creating a potential space, pusing dura mater away from scull and pooling.
Explain the subdural space
Potential space between the dura and the arachnoid mater
What happnes if you get a blood vessel that bursts in the subdural space?
Blood will pool and seperate the arachnoid matter from the dura matter.
Explain the extradural space and subdural space in an x-rays
Extradural= dura is thick tight boundry so it is a clear boundry.
Subdural= not as clear, fuzzy boundry
Deep to the arachnoid mater – only normally occurring fluid-filled space of the meninges
Subarachnoid space
Explain Cerebral Spinal Fluid
- Produced by the choroid plexus (primarily in the ventricles of the brain) (FROM BLOOD)
- CSF returns to the venous system through arachnoid villi
- Arachnoid granulations (clumps of arachnoid villi) into the superior sagittal sinus
protective barrier and floats brain
Clumps of arachnoid vili that project for into superior sagital sinus and return liquid portion of CSF back to the heart.
Arachnoid granulations
Surgery and injury to scalp can result in what?
Hematoma forming and moving losley through the loose connective tissue of the scalp.
A tear into the cerebral vein where it crosses the dura to enter the cranial venous sinus can result in what?
a subdural hematoma
Ruptured anuerysm of vessles of the cerberal arterial circle hemmorage directy into the ?
Subarachnoid space and CSF
Dural Folds
Mowhawk, Down the middle, sperates cerebral cortex (R/L)
Falx cerebri
Dural Folds
Splits bewteent the cerebellum
Falx cerebelli
Dural Folds
Shelf of dura matter, covers the entrire posterior cranial fossa
Tentorium cerebelli
Dural Folds
Dura matter that covers the pituitary glad in place on the sellae turnica.
Diaphragma sellae
Vasculature – Arterial Supply
- Branches from ethmoidal arteries (ophthalmic a. via internal carotid a.)
blood supply of anteiror fossa
Anterior meningeal arteries
- Branch from the maxillary artery
- Enters the cranium via the foramen spinosum
Middle meningeal arteries
Rupture= extradural hematoma
- Branch from the ascending pharyngeal artery
- Meningeal branch from the occipital artery
- Meningeal branch from the vertebral artery
Posterior fossa
Posterior Meningial Artery
What is the nerve that provides main sensory nerves of the head?
Trigeminal Nerve CN5
Ophthalmic division (V1)
Falx cerebri
Tentorium cerebelli
Anterior floor
Maxillary division (V2)
Middle cranial fossa
Mandibular division (V3)
Follows distribution of middle meningeal artery
The brain has no pain receptors but the ____ has sensory signals. **pain originates from here!*
Dura Mater
What is the sensory innervation of the posterior fossa?
Cervical nerves C1/C2
If you get stiff neck muscles in the back of neck/head innervated by posterior rami C2/C3 and you have rami from C1/C2 going up to the dura this results in what?
You have reffered tensions headaches in the back of our head.
Pain relayed back through C1/C2
Where do all the dural venous sinuses eventually drain?
Internal Jugular Vein
Dural Venous Sinuses
Across the top of the head
Most external
Superior Sagittal Sinus
Dural Venous Sinuses
Run on inferior portion of faux
Inferior sagittal Sinus
Dural Venous Sinuses
The inferior sagittal sinus goes posterior and joins with what?
The great Cerebral Vein
Dural Venous Sinuses
The great cerebral vein and the inferior sagittal vein join to become what?
The straight Sinus
Dural Venous Sinuses
The posterior merging of the straight sinus and the superior sagital sinus results in?
The confluence of sinuses
small occipital sinus joins as well
Dural Venous Sinuses
Laterally, travels anterior from the confluence of sinuses towards the sigmoid sinus.
Transverse Sinus
Dural Venous Sinuses
Laterally, from the transverse sinus into ___
Sigmoid Sinus
Dural Venous Sinuses
The sigmoid sinus heads towards the jugular foramen to exit and empty down into the?
Cavernous sinus and then internal jugular
Dural Venous Sinuses
Drain the anterior portion of skull and both join togehter.
Superior petrosal sinus
Inferior petrosal sinus
Basilary sius is anteiror side
Explain cavernous Sinus
Sits around the sellae turcica and pituitary glad. Meet on either side. Lots of nerves and blood vesses run through. it.
What 2 structures pass THROUGH the cavernous sinus?
- Internal carotid artery
- Abducent nerve (CN 7)
What structures are on the lateral wall of the cavernous sinus?
- Oculomotor nerve (CN 3)
- Trochlear nerve (CN 4)
- Ophthalmic nerve (CN V1)
- Maxillary nerve (CN5 V2)
What occurs if thrombosis or aneurysim of ICA (push out) occurs in the area of the cavernous sinus?
Lots of nerves in the area so pt. will experiance pain very rapid and onset, nerves will be damaged.
CN 3,4,5 V1,V2, V6
Explain 12 cranial nerves
- Olfactory (Through olfactory bulb crib plate, to nose)
- Optic (through optic canal; eye)
- Oculomotor (Superior orbital fissure)
- Trochlear (Superior Orbital Fissure)
- Trigeminal (branches superior orbital fissure V1, foramen rotundum V2, foramen ovale V3)
- Abducent (superior orbital fissure)
- Facial (Internal acoustic meatus)
- Vestibulocochlear (internal acoustic meatus)
- Glossopharyngeal (Jug foramen)
- Vagus (jug foramen)
- Accessory (jug foramen)
- Hypoglossal (hypoglossa canal)