Cranium & Brain Flashcards
What are the cranial roof & base in the neurocranium?
- cranial roof: frontal, occipital & 2 parietal bones
- cranial base: frontal, sphenoid, ethmoid, occipital, parietal & temporal
What is the function of the neurocranium?
- surrounds & protects the brain
- houses middle & ear structures
What is the viscerocranium?
facial bones
What bone is the ONLY moveable bone of the skull?
mandible
What are the bones of the viscerocranium?
- nasal (2)
- maxillae (2): attachment for facial expression
- zygomatic (2): cheek bones
- lacrimal
- vomer: fkat bone that forms nasal septum
- palatine (2)
- mandible
What are the bones of the neurorocranium?
- ant: frontal, ethmoid, & sphenoid
- lat: pariteal (2) & temporal (2)
- post: occipital
Which cranial bone is the keystone for the cranial floor & is in contact with all other cranial bones?
sphenoid bone
What can be seen from the anterior view of the cranium?
- glabella
- facial bones -> maxillae
- frontal & parietal
- orbits -> eye support
What can be seen from the lateral view of the cranium?
- zygomatic arch (high yield)
- temporal fossa ( above arch) & infratemporal fossa (below arch)
- ext. accoustic meatus
- styloid & mastoid processes
What can be seen from the posterior view of the cranium?
- lambda
- mastoid process
- occipital & parietal bones
- ext. occipital protuberance
What can be seen from the superior view of the cranium?
- cranium roof -> calvarium
- coronal suture: separates frontal from parietal
- sagittal suture: separates right & left parietal
- lambdoid suture: separates occipital from right & left parietal
What are the boundaries of the internal cranial base?
- ant: frontal, sphenoid, ethmoid bones
- middle: parietal & temporal bones
- post: squamous of occipital bone
What is the anterior cranial fossa?
- formed by lesser wings of sphenoid, ethmoid, & bone
- supports frontal lobes & forms roof of orbits
What is the middle cranial fossa?
- formed by greater wings of sphenoid & squamous (lat) & petrous (post) of temporal bones
- spports temporal lobes
What is the posterior cranial fossa?
- fromed by occipital & temporal bones
- contains cerebellum, pons, medulla
What are the nerves of the cranial fossa?
- olfactory -> ciribriform palate
- optic -> optic canal
- oculomotor, abducens & trochlear-> sup orbital fissure
- trigeminal -> sup orbital fissure & foramen rotundum/ovale
- vestibulocochlear & facial -> int. acoustic meatus
- glossopharyngeal, vagus, & accessory -> jugular foramen
- hypoglossal -> hypoglossal canal
What is the name for the soft spot on an infants skull?
fontanelles
What is the name of the area of the skull overlying the middle meningeal artery?
pterion
What are the 3 layers of the cranial meninges?
- dura mater: tough, thick ext. fibrous layer
- arachnoid mater: thin intermediate avascular
- pia mater: delicate int. vascular layer
What are the 2 layers of the dura mater?
- periosteal: lies closest to calvarium
- meningeal: lies closest to brain tissue
What lies in between to the 2 layers of the dura mater?
dural venous
What is the arterial supply of the dura mater?
middle meningeal art & vein
What nerve runs through the dura mater?
trigeminal
What are the 4 folds of the dura mater?
- falx cerebri -> separates cerebral hemis
- tentorium cerebelli -> separates cerebellum from cerebrum
- falx cerebelli -> partially separates 2 cerebellar hemis
- diaphagma sellae -> separates pituitary from base of brain
What are the 6 dural sinuses & where do they drain?
- sup sagittal -> drains into confluence sinus
- inf sagittal -> drains into straight sinus
- straight -> drains into confluence sinus
- confluence -> drains into transverse sinus
- transverse -> drains into sigmoid sinus
- sigmoid -> drains into int. jugular
What are the unpaired venous sinuses?
- sup sagittal
- inf sagittal
- straight
- occipital
- ant. & post. intercavernous
What is the paired venous sinus?
- cavernous sinus= anatomic jewel box
- allows heat exchange
What crosses the cavernous sinus?
- int carotid art
- carotid plexus
- CN 3, 4, 6, V-1, & V-2
What is the arachnoid mater?
- sits b/w dura & pia
- no art supply or inn
- has subarachnoid space -> space b/w dura & pia mater
- has arachnoid granulations
What is the pia mater?
- highly vascularized
- has perivascular (Virchow Robin) space -> b/w vessel walls & pia mater to regulate fluid movement/drainage & lymphatic system
What are the meningeal spaces?
- epidural: b/w roof of skull & sup. surface of dura
- subdural: b/w meningeal layer of dura & arachnoid mater
What connects the 2 hemispheres of the cerebrum?
corpus callosum
What is the forebrain (prosencephalon)?
- largest part of the brain
- contains cerebrum, thalamus (sense- NOT smell), hypothalamus (hormone), pituitary, olfactory, limbic system (behavior)
What are the 4 lobes of the cerebrum?
- frontal -> intelligence, problem solving, reading/speaking/language
- parietal -> sensation, knowing left from right
- occipital -> vision
- temporal -> hearing
What does the forebrain (prosencephalon) split into?
- telencephalon -> cerebral lobes & basal ganglia
- diencephalon -> epithalamus, thalamus, hypothalamus, subthalamus
What are the structures of the limbic system?
- hippocampus: memory center; associate memories with various senses
- amygdala: emotion, feelings, fear, pleasure
Damage to what system is the cause of dementia?
limbic system
What is the midbrain (mesencephalon)?
- most sup.
- connects brain & spinal
- art supply: basilar art
- responsible for eye movement via CN 3
What is the hindbrain (rhombencephalon)?
- pons -> regulates breathing, sleep cycles
- medulla oblongata -> where brain becomes spinal cord
- cerebellum -> post to pons & medulla
- cooridinates sensation with muscle movement, balance & posture via CN 5-12
What plexus is in the ventricular system?
choroid plexus -> formed by epidymal cells lining ventricles & produces CSF
What is the ventricular flow in the brain?
lat ventricle -> inter. foramen (foramen of monroe) -> 3rd ventricle -> cerebral aqueduct -> 4th ventricle -> suarachnoid space or central spinal canal
What is hydrocephalus?
increased pressure b/c of excess CSF fluid build up in the brain
What is the name of the circle where terminal branches of arteries form an anastomotic circle?
Circle of Willis
What arteries create the Circle of Willis?
- ant. cerebral art. -> terminal branches of int. carotid art
- int carotid art -> prox to origin of middle cerebral art
- post. cerebral art. -> end branches of basilar art
- ant communicating art. -> connects 2 left & right ant cerebral art.
- post communicating art -> connects ICA to post cerebral art
What are the branches of the internal carotid system?
- int carotid
- post. communicating art (PCA): anastomotic “connecting vessel” in the circle of Willis
- ant. cerebral art: supplies part of cerebrum
The interior carotid arteries continue as what artery?
middle cerebral art
How do the internal carotid arteries enter the brain?
via carotid canal
How do vertebral arteries enter the cranial cavity?
via foramen magnum
When the 2 vertebral arteries in the brain converge, what artery does it form?
basilar art ->bifuricates into post cerebral art
What is the regional blood supply to the cerebrum?
- ant cerebral art: supply anteromedial portion
- middle cerebral art: supply majority of lat portion of brain
- post cerebral art: supply both medial & lat parts of post portion
What is an ischemic stroke?
causes by obstruction of cerebral art
What is a hemmorrhagic stroke?
caused by ruptured art or berry aneurysm
