Exam3Lec7SkullandBrain Flashcards
What are the compartments of the skull?
Cranial cavity (brain)
2 Auditory (ears)
2 Orbit (eyes)
Oral cavity (mouth)
Infratemporal fossa (lat. skull)
Pterygopalatine fossa (lat. skull)
The skull compartments are spaces in the skull that protect important structures
What is the neurocranium of the cranial vault of the skull
Neurocranium (Calvaria) = skull cap
Frontal
Parietal
Occipital
Sphenoid
Temporal
low yield
What is the Viscerocranium?
Viscerocranium = facial bones
Maxillary
Nasal
Zygomatic
Palatine
Lacrimal
Inferior Nasal Conchae
My Neighbor Zack Picks Lillies Intensely
| high yield
What is the cranial fossa of the skull?
depression in the cranial cavity floor
high yield
What are the the three cranial fossa’s?
Anterior
middle
posterior
What structures are located in the anterior cranial fossa?
Cribriform plate
high yield
we see olfactory n.
What structures are located in the middle cranial fossa?
Foramen rotundum + ovale + spinosum
Carotid canal
Optic canal
Superior orbital fissure
high yield
What structures are located in the posterior cranial fossa?
Jugular foramen
Foramen magnum
Internal acoustic meatus
Hypoglossal canal
high yield
Accessory n. (CN 11) passes into Foramen Magnum then enters Jugular Foramen
Orientation of the brain
Rostral = anterior
Caudal = posterior
Dorsal = superior
Ventral = inferior
very low yield
What are the two nervous system?
CNS = brain + brainstem + spinal cord
PNS = everything else
-Somatic = motor + sensory innervation
-Autonomic = sympathetic + parasympathetic innervation
What are nerve cells?
Nerve cells = neurons
Dendrites (short processes) receive signals from other neurons –>soma (cell body) –>axons (long processes) conduct signals away
What are glial cells?
support nerve cells –>ex: oligodendrocytes (in CNS) form myelin sheath around axons
very low yield
What are the lobes of the brain?
Frontal
Parietal
Occipital
Temporal
What are the Important Landmarks of the cerebral hemispheres and lobes?
Longitudinal Sulcus = divides right + left hemispheres
Central Sulcus = separates frontal + parietal lobes
Lateral Fissure = separates temporal from frontal + parietal lobes
Parietooccipital Sulcus = separates parietal + occipital lobes
Cingulate Sulcus = deep to frontal + parietal lobes
What is the ventricular system of the brain?
Ventricular system = network of 4 ventricles in the brain
2 Lateral ventricles
3rd ventricle
4th ventricle
Choroid plexus –> lines the ventricles & produces cerebral spinal fluid (CSF)
What is the ventricular system flow of the brain?
Lat. ventricle –>Interventricular foramen (of Monroe)–> 3rd ventricle –>Cerebral aqueduct–> 4th ventricle
Flow of CSF into subarachnoid space = 4th ventricle –> Foramen of lushka –>Cisterna magna –>Subarachnoid space ( this is low yied)
What is hydrocephalus?
Hydrocephalus = increased pressure d/t excess CSF fluid build up in the brain
Cause = dilation or obstruction of the lateral (or sometimes 3rd ) ventricle
high yield
What are meninges?
Layers of CT b/n the scalp & brain –> fxn = protection
What is dura mater?
outer layer of meninges–>splits into 2
* Periosteal division connects to scalp
* Meningeal division connects to arachnoid mater
- this division Give rise to dural sinus Falx Cerebri –> contains sup. and inf sagittal sinus
What is arachnoid mater of meninges?
middle layer
Contains arachnoid granulations
Drain CSF–> into Dural sinus
What is Pia Mater of meninges?
inner layer
What are the potential spaces of the meninges?
- Epidural space = b/n the skull + dura mater
- Subdural space = b/n the dura + arachnoid mater
-
Subarachnoid space = b/n the arachnoid + pia mater
-Contains cerebral “bridging” veins that drain into–> Dural sinus (this is a for sure space, not potential)
need to know last one, hy
What are dural sinuses of the brain?
Large channels containing (venous) blood
What is falx cerebri?
contains sup. + inf. sagittal sinuses
Formed by dura mater (superficial layer)
know this
What are the different types of dural sinuses
Superior sagittal =drains into confluence sinus
Inferior sagittal =drains into straight sinus
Straight =drains into confluence sinus
Confluence =drains into transverse sinus
Transverse=drains into sigmoid sinus
Sigmoid =drains into internal jugular vein (IJV)
Cavernous =drains into cerebral “bridging” veins
drainage is low yield, be familiar with names and superior sagittal since we talked abt it
All the Dural sinuses eventually drain into
the IJV
know this
The brain (cerebellum) is supplied by what?
Circle of Willis
The circle of willis is comprised of what two systems that provide vascularzation to the brain?
Internal Carotid System and Vertebro-basilary System
Which arteries are part of the the internal carotid system?
Anterior (ACA) + Middle (MCA) Cerebral arteries
Anterior + Posterior Communicating arteries
Anterior Choroidal arter (this pt is low yield)
ACA = Ant. cerebrum
MCA= Lat. cerebrum
Which arteries are part of the Vertebro-basilary system?
Vertebral arteries
Basilar artery
Posterior Cerebral artery (PCA)
PCA =Post. cerebrum
What connects the internal carotid system and the verterbro-basilary system?
post communicating artery
What are hematoma’s?
Collection (or pool) of blood outside of the blood vessel
What are the two types of hematomas?
epidural
subdural
What is the shape, blood supply, location, and patient type of epidural hematoma?
does NOT cross suture lines
Shape = biconvex (lens)
Blood supply = middle meningeal artery
Location = b/n skull + dura mater –> epidural space
Patient type = adolescents & young adults (trauma injuries)
Middle Meningeal Artery = Foramen Spinosum
What is the shape, blood supply, location, and patient type of subdural hematoma?
crosses suture lines
Shape = crescent
Blood supply = cerebral (bridging) veins
Location = b/n dura + arachnoid mater
Patient type = elderly & alcoholics
Cerebral bridging Veins = Subarachnoid Space
What are hemorrhages?
Active bleeding into the surrounding brain tissue
What are the two types of brain hemorrhages?
subarachnoid, intracerebral
Subarachnoid Hemorrhage
NOT in the ventricles
Cause = rupture of a berry aneurysm
Location = subarachnoid space
Blood supply = circle of Willis
Risk factor = polycystic kidney disease
still note this
Intracerebral Hemorrhage
in the ventricles
Cause = hypertensive vasculopathy
Location = ventricles + parenchyma (tissue)
Blood supply = penetrator arteries (br. off circle of Willis)
very low yield, also mri image lw
What connects the internal carotid system and the verterbro-basilary system?
post communicating artery
True or false, Cranial nerves are mostly located in the brainstem
True but with exceptions=olfactory (CN 1) + optic (CN 2)
List the cranial nerves and where they enter.
I) Olfactory =cribriform plate
(II) Optic =optic canal
(III) Oculomotor =superior orbital fissure
(IV) Trochlear =superior orbital fissure
(V) Trigeminal =sup. orbital fis. + foramen rotundum / ovale
(VI) Abducens =superior orbital fissure
(VII) Facial =internal acoustic meatus
(VIII) Vestibulocochlear = internal acoustic meatus
(IX) Glossopharyngeal = jugular foramen
(X) Vagus =jugular foramen
(XI) Accessory=jugular foramen
(XII) Hypoglossal =hypoglossal canal
For the cranial nerves that are sensory, what do they innervate?
Olfactory (CN I) = nose
Optic (CN II) = eye
Vestibulocochlear (CN VIII) =inner ear
For the cranial nerves that are motor, what do they innervate?
Oculomotor (CN III) =all eye muscles (except sup. oblique + external/lat. rectus m.)
Trochlear (CN IV) =superior oblique m. (eye)
Abducens (CN VI) =external + lateral rectus m. (eye)
Accessory (CN XI) =trapezius + SCM (neck)
Hypoglossal (CN XII) =all tongue muscles (except palatoglossus m.)
For the cranial nerves that are both sensory and motor, what do they innervate?
Trigeminal (CN V) =face + teeth + muscles of mastication
Facial (CN VII) =muscles of facial expression + submandibular / sublingual glands + stylohyoid m. + post. belly of digastric m.
Glossopharyngeal (CN IX) =stylopharyngeus + parotid gland + tongue
Vagus (CN X) =heart + respiratory structures + GI tract + external ear
Vagus n. = palatoglossus, palatopharyngeus, salpingopharyngeus, pharyngeal constrictors
What is the cerebellum?
Little brain” structure located near the brainstem
Organized into ant. / mid. / inf. peduncles
What is the function of the cerebellum?
coordination of voluntary movement
maintaining balance + posture
hy
Basal nuclei also have role in voluntary movement
What is the arterial supply of the Cerebellum?
brs. of vertebro-basilar system
Posterior Inferior Cerebellar artery (PICA)
Anterior Inferior Cerebellar artery (AICA)
Superior Cerebellar artery
hy
Hypothalamus
Innervation=: has PNS-> autonomic–> symp + parasymp inn
fxn: regulating bodily processes + hormones
Made up of many small nuclei ( low yield pt):
Paraventricular nucleus
Supraoptic + preoptic nuclei
Ventromedial nucleus
Arcuate nucleus
Hormonal response = slow
Autonomic response = fast
What is the Hypophyseal stalk ?
connects to the pituitary gland
The pituitary gland is comprised of:
Adenohypophysis = anterior pituitary gland
Stimulated by hypothalamus to release hormones
Neurohypophysis = posterior pituitary gland
Stores hormones produced by the hypothalamus
Thalamus
PNS –> somatic –>sensory + motor inn.
Function = relay station –> pathways project to cerebral cortex & regulate info transfer
Composed of many small nuclei
What is the Thalamic Pathway?
- Spinothalamic = pain + temperature (from periphery)–>CNS
- Dorsal Nucleus Medial Lemniscus (DCML) = proprioception (from periphery) –>CNS
- Corticospinal = CNS–> periphery for limb movement
What is the spinothalamic pathway?
Transmit pain + temp. signals from periphery to brain (CNS)
- Pain stimulus (hit your hand on a nail)
- Nerve fibers deliver pain signals from periphery to spine
- Nerves synapse onto 1st order neurons (dorsal root ganglia)
- 1st order neurons synapse onto 2nd order neurons (dorsal horn) in spinal cord
- Signals cross the midline of spinal cord = travel up contralateral side of spine
- Neurons synapse onto 3rd order neurons (thalamus-brain
) - Thalamus sends pain signals to the somatosensory cortex
Stimulus –>1st order neurons –>2nd order neurons travel to contralateral side –> 3rd order neurons–>Pain crosses midline –> travels up contralateral side of spine
What is the DCML pathway?
- Transmit proprioception signals from periphery to brain (CNS)
- Sensation of proprioception
- Nerve fibers deliver signals from periphery to spine
- Nerves synapse onto 1st order neurons (dorsal root ganglia)
- 1st order neurons remain ipsilateral up spine into brain
- Synapse onto 2nd order neurons (dorsal nuclei in brainstem)
- Signals cross the midline –> travel into brain
- Neurons synapse onto 3rd order neurons (thalamus)
- Thalamus sends propriooception signals to the somatosensory cortex
remian same sife of sc until we reach brainstem
1st order neurons –> stays ipsilateral up spine –>2nd order neurons –>crosses midline–> 3rd order neurons
What is the corticospinal pathway?
- Transmit motor signals from brain (CNS) to periphery
- Motor cortex of the brain (CNS)
- Nerve fibers deliver signals from CNS to corticospinal tract
- Alpha motor neurons (in spinal cord) carry out movement
no 1st order , 2nd order, etc.
Motor cortex (CNS) –>alpha motor neurons (spinal cord) –>periphery for limb movement
What is this MRI image?
Epidural Hematoma
What is this MRI image?
Epidural Hematoma
What is this MRI image?
Subdural Hematoma
