Brain & Meninges (Part 1)

Question 1

cranial meninges

Answer 1

The outermost covering of the brain Consist of three connective tissue membranes that envelop the brain and spinal cord Membranes lie between the nervous tissue and bone

Question 2

cranial meninges: primary functions

Answer 2

Primary function is to protect the CNS Form a supporting framework for arteries, veins, and venous sinuses Enclose the subarachnoid space, which is vital for the normal function of the brain

Question 3

cranial meninges: 3 connective tissue layers

Answer 3

1. Dura mater: tough thick external fibrous layer 2. Arachnoid mater: thin intermediate layer 3.Pia mater: delicate internal vascularized layer

Question 4

meninges: dura mater

Answer 4

Tough outer covering of the brain Consists of 2 layers Innervated mostly by CN 5 Very well vascularized

Question 5

meninges: dura mater (2 layers)

Answer 5

1. Periosteal: pressed closely against cranial bones 2. Meningeal

Question 6

Periosteal layer

Answer 6

Firmly attached to skull Continuous with skull periosteum at foramen magnum

Question 7

Meningeal layer

Answer 7

In close contact with arachnoid mater Continuous with spinal cord meningeal dural covering

Question 8

Two layers of dura are closely associated in all areas except where?

Answer 8

venous sinuses and dural infoldings

Question 9

dural infoldings (4)

Answer 9

1. Falx cerebri 2. Tentorium cerebelli 3. Falx cerebelli 4. Diaphragma sellae

Question 10

dural infoldings: falx cerebri

Answer 10

Largest dural infolding Lies in the longitudinal cerebral fissure Separates right and left cerebral hemispheres

Question 11

dural infoldings: falx cerebri (attachment site and end site )

Answer 11

Attached to crista galli anteriorly, and internal occipital protuberance posteriorly Ends by becoming continuous with tentorium cerebelli

Question 12

dural infoldings: tentorium cerebelli

Answer 12

Second largest dural infolding Separates occipital lobes from the cerebellum

Question 13

dural infoldings: tentorium cerebelli (attachments)

Answer 13

Anterior clinoid process Petrous part of temporal bone Internal surface of occipital bone

Question 14

dural infoldings: falx cerebelli

Answer 14

Vertical dural infolding Inferior to tentorium cerebelli Separates cerebellar hemispheres

Question 15

dural infoldings: Diaphragma sellae

Answer 15

Smallest dural infolding Suspended between anterior and posterior clinoid processes Forms roof over hypophysial fossa

Question 16

meninges: arachnoid mater

Answer 16

Thin, avascular membrane Filled with a “web” of collagen – shock absorber Only enters the longitudinal fissure, otherwise not present in any other sulci or fissures

Question 17

meninges: arachnoid mater (contains)

Answer 17

Contains cerebrospinal fluid in the subarachnoid space

Question 18

meninges: pia mater

Answer 18

Thin, delicate membrane Completely lines all fissures and sulci of the brain Highly vascularized Tightly adherent to brain surface and cranial nerve roots

Question 19

meninges: pia mater (tear/rupturing)

Answer 19

Location of all intracerebral hemorrhages leads to intracranial hemorrhage (aka cerebrovascular accident)

Question 20

clinical correlation: meningitis

Answer 20

Inflammation of the meninges

Question 21

clinical correlation: meningitis (symptoms)

Answer 21

Severe headache Fever Photophobia Stiff neck

Question 22

clinical correlation: meningitis (cause)

Answer 22

Can be caused by bacteria or viruses Most cases are viral and relatively benign Bacterial meningitis is extremely serious and fatal if not treated promptly

Question 23

dura mater: vascular supply( 3 aa.)

Answer 23

Middle meningeal artery: largest supplier of blood Anterior meningeal arteries: branches from ethmoidal arteries Accessory meningeal artery: branch of maxillary artery

Question 24

leptomeninges

Answer 24

pis & arachnoid mater

Question 25

Arachnoid trabeculae

Answer 25

Thin strands of connective tissue Extend down and become continuous with pia mater Loosely connect the arachnoid and pia layers

Question 26

meningeal spaces: extradural/ epidural

Answer 26

Potential space between periosteal layer of dura and skull Typically due to bleeding from blunt head trauma Herniation can occur within hours if hemorrhage is not evacuated

Question 27

meningeal spaces: extradural/ epidural (classical presentation)

Answer 27

brief loss of consciousness after injury, followed by lucid period, followed by loss of consciousness, followed by death.

Question 28

meningeal spaces: subdural

Answer 28

Potential space between meningeal layer of dura and the arachnoid Caused by tearing of a bridging vein secondary to blunt trauma: bridging veins are sheared during acceleration-deceleration of the head

Question 29

meningeal spaces: subdural -- T/F subdural usually located on the opposite side of trauma?

Answer 29

T

Question 30

meningeal spaces: subarachnoid

Answer 30

Real space between arachnoid and pia Contains CSF and blood vessels Lines surface of brain and the gyri, but does not enter sulci of brain like pia mater Often caused by rupture of intracranial aneurysm

Question 31

meningeal spaces: subarachnoid (classical presentation)

Answer 31

sudden onset thunderclap headache with some level of confusion

Question 32

brain divisions (4)

Answer 32

1. Cerebrum: telencephalon 2. Cerebellum 3. Diencephalon: thalamus & hypothalamus 4. Brainstem: mesencephalon, pons, medulla oblongata

Question 33

Cerebrum lobes (4)

Answer 33

1. frontal 2. parietal 3. temporal 4. occipital

Question 34

Cerebrum lobe: frontal

Answer 34

Personality, behavior, emotion Judgment, planning, problem solving Intelligence, concentration, self-awareness Movement (motor cortex)

Question 35

Cerebrum lobe: parietal

Answer 35

Sensory information: touch, temperature, pain Interpretation of visual and spatial information Interpretation of language and words

Question 36

Cerebrum lobe: temporal

Answer 36

Understanding language Hearing Memory

Question 37

Cerebrum lobe: occipital

Answer 37

vision

Question 38

cerebellum

Answer 38

coordinates muscle movement Controls balance Lies beneath tentorium cerebelli in the posterior cranial fossa

Question 39

brain stem

Answer 39

Involuntary reflexes Crucial basic life functions (Heart rate, Breathing, Blood pressure)

Question 40

thalamus & hypothalamus (Aka diencephalon)

Answer 40

Relay information to appropriate brain centers for processing Control pituitary hormones Control hunger, thirst, sleep, sexual response Aka diencephalon

Question 41

cerebral vascular supply

Answer 41

ICA: supports most of the cerebrum Vertebral arteries: brainstem, cerebellum, posterior cerebrum

Question 42

Internal Carotid A. (ICA)

Answer 42

Branches off the common carotid Enters skull via carotid canal Passes through cavernous sinus

Question 43

Internal Carotid A. (ICA) -- gives off?

Answer 43

Ophthalmic artery Posterior communicating artery Anterior cerebral artery Middle cerebral artery

Question 44

vertebral aa.

Answer 44

Branch off the subclavian arteries Pass bilaterally through transverse foramina of C1-6 Enter cranial cavity via foramen magnum

Question 45

vertebral aa. join to form basilar a. and becomes?

Answer 45

Becomes posterior cerebral artery pair Supplies brainstem, cerebellum, and posterior cerebrum

Question 46

circle of willis

Answer 46

Anastomosis between ICA and vertebrobasilar system

Question 47

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Question 48

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Question 49

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Question 50

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Question 51

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Question 52

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Question 53

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Question 54

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Question 55

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Question 56

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Question 57

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Question 58

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Question 59

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Question 60

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