Cranial Cavity Flashcards
What is the neurocranium? What are the parts of the neurocranium?
. Bony covering of the brain and the cranial meninges
. Calvaria (skull cap)
. Basicranium (floor or cranial base)
What are the two parts of the cranium?
. Neurocranium
. Viscerocranium
Which 8 bones form the neurocranium?
. Frontal . Ethmoid . Sphenoid . Occiptal . Temporal (2) . Parietal (2)
What is the viscerocranium and what 15 bones make it up?
. The viscerocranium is made up of facial bones that developed mainly from the mesenchyme of the embryonic pharyngeal arches . The viscerocranium forms the anterior part of the cranium . Ethmoid . Mandible . Vomer . Maxilla (2) . Inferior nasal concha (2) . Zygomatic (2) . Palatine (2) . Nasal (2) . Lacrimal (2)
What is the point where the frontal, sphenoid, temporal, and parietal bones come together?
Pterion
What is the name of the palpable bump on the back of the head?
External occiptal protuberance
What is lambda and where is it?
. It is the point between the sagittal and lambdoid sutures
. Located above the occipital bone
What bones do the coronal, sagittal, and lambdoid sutures connect?
. Coronal suture = frontal + parietal bones
. Sagittal suture = parietal bones
. Lambdoid suture = occipital + parietal bones + temporal bones
What is bregma and where is it?
. Connection of coronal and sagittal sutures
What is the vertex and where is it?
Most superior part of the skull, mid-sagittal suture
What is the hard palate formed by?
Palatine processes of the maxillae and the horizontal plates of the palatine bones
What is the vomer?
Thin, flat bone that forms a portion of the nasal septum
What are the choanae? Where are they?
. Posterior nasal apertures
. Its inferior boundary is formed by the posterior edge of the hard palate
. The nasal apertures are separated from each other by the vomer
What do the occipital condyles articulate with?
C1 vertebra
The cranial cavity has three cranial fossa. What does each hold?
. Anterior cranial fossa supports the frontal lobes
. Middle cranial fossa supports the temporal lobes and the pituitary
. Posterior cranial fossa supports the pons, medulla, cerebellum
Which three bones form the anterior cranial fossa?
. Frontal
. Ethmoid
. Body and lesser wing of sphenoid
What is the crista galli?
. Ridge of bone that projects from the ethmoid bone
. Makes up the cribriform plate of the ethmoid bone
. Olfactory foramina are the holes in the cribriform plate
Which two bones form the middle cranial fossa?
. Greater wings of sphenoid
. Squamous and petrous parts of temporal bones
What are the three parts of the sella turcica and what borders it?
. It is bordered by the anterior/posterior clinoid processes
. Tuberculum sellae
. Hypophysial fossa
. Dorsum sellae
What are the sphenoidal crests?
Posterior border of the lesser wings of the sphenoid, end as the anterior clinoid processes
What is the prechiasmatic sulcus?
Extends between the left and right optic canals… anterior to the tuberculum sellae
Which bones form the posterior cranial fossa?
Mostly occipital, with contributions from sphenoid and temporal
What is the clivus?
The dip from the sella turcica that leads to the foramen magnum
What is the internal occiptal crest?
. It divides the posterior part of the posterior cranial fossa into two cerebellar fossa (its a line perpendicular to the foramen magnum)
. It ends superiorly as the internal occipital protuberance
What are the two layers of the dura mater?
. External periosteal layer
. Internal meningeal layer
Blood supply and innervation of the dura?
. Middle meningeal artery (anterior/posterior branches)
. Meningeal branches of V1, V2, V3, and to a lesser extent C2 and C3 via X and XII
When the internal meningeal layer reflects away from the external periosteal layer, what 4 infoldings does it create?
. Falx cerebri
. Falx cerebelli
. Tentorium cerebelli
. Diaphragma sellae
Describe what the 4 dural infoldings separate.
. Falx cerebri = two cerebral hemispheres
. Falx cerebelli = partially the two cerebellar hemispheres
. Tentorium cerebelli = cerebellum from occipital cerebrum (leaves a gap anteromedially called the tentorial notch)
. Diaphragma sellae = covers pituitary (suspends between clinoid processes)
The internal meningial layer also creates the dural sinuses, which drain into what?
IJV
What are the lateral venous lacunae?
Lateral expansions of the superior sagittal sinus
What are arachnoid granulations?
. They transfer CSF to the venous system
. Prolongations of arachnoid mater that pierce the meningeal layer of the dura mater
Where does the superior sagittal sinus receive blood from and where does it end?
. Superior cerebral veins
. Confluence of sinuses
Where does the inferior sagittal sinus drain?
Straight sinus
Which two structures form the straight sinus and where does it drain?
. Inferior sagittal sinus + great cerebral vein
. Confluence of sinuses
What sinus does the transverse sinus become? And where does this sinus drain?
. Sigmoid sinus
. IJV at jugular foramen
What does the occipital sinus communicate with?
. Internal vertebral sinus
Where is the cavernous sinus and where does it receive blood from?
. Its on both sides of the sella turcica
. Superior/inferior opthalmic veins
. Superficial middle cerebral vein
. Sphenoparietal sinus
Where are the superior and inferior petrosal sinuses?
. The superior petrosal sinus joins the cavernous sinus to the transverse sinus
. The inferior petrosal joins the cavernous sinus to the origin of the IJV
What is the basilar plexus?
. It connects with the inferior petrosal sinuses and communicates with the internal vertebral venous plexuses
What are emissary veins?
. They connect the dural sinuses to veins outside the cranium
. They connect the cavernous sinus to the pterygoid venous plexus
The lateral walls of the cavernous sinus contain which nerves and what artery?
. CN III . CN IV . CN V1 . CN V2 . (distal portion) Internal Carotid Artery
What covers the ICA and which nerve crosses over it within the cavernous sinus?
. Carotid plexus of sympathetic nerves
. CN VI
What are the 4 parts of the ICA?
. Cervical
. Petrous
. Cavernous
. Cerebral
What is the leptomeninx?
Arachnoid and pia maters
Where is the CSF?
The space between the arachnoid and pia, the subarachnoid space
What is the blood supply and innervation to the arachnoid mater?
None!
The pia mater is _______ vascularized
highly
What does the pia mater do in relation to the cerebral arteries?
When the cerebral arteries penetrate the cerebral cortex, the pia follows them for a short distance, creating a pial coat and periarterial space
What is the innervation of the pia mater?
None!
What are the three meningeal spaces and which of them is a true space?
. Dura-cranium interface (extradural or epidural space)
. Dura-arachnoid junction (subdural space)
. Subarachnoid space = true space between arachnoid and pia
Generally, trauma involving which artery creates an epidural hematoma?
. Middle meningeal artery
. So epidural hematomas are arterial in nature
Is a subdural hematoma venous or arterial in nature?
Venous
What is in the subarachnoid space?
. CSF
. Trabecular cells
. Cerebral arteries
. Bridging superior cerebral veins that drain into the superior sagittal sinus
Is a subarachnoid hematoma venous or arterial in nature?
Arterial
What is a Le Fort I fracture?
Horizontal fracture of the maxilla
What is a Le Fort II fracture?
. Fracture passes through the posterolateral parts of the maxillary sinus, superomedially through the infraorbital foramina, lacrimals, or ethmoids to the bridge of the nose
. The entire central part of the face is separated
What is a Le Fort III fracture?
. Horizontal fracture that passes through the superior orbital fissures, ethmoid and nasal bones, and extends laterally through the greater wings of the sphenoid and the frontozygomatic sutures
