B5.052 Skull, Scalp, Cranial Fossa, Nose and Paranasal Sinuses Flashcards

1
Q

skull functions

A

protects brain
exclusive site of 4/5 sense: sight, olfaction, taste, hearing
openings of both respiratory and digestive tracts

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2
Q

what is the diploic space

A

space in between the inner and outer table of cortical bone

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3
Q

causes of widening of the diploic space

A
sickle cell anemia
thalassemia
iron deficiency anemia
renal osteodystrophy
hyperparathyroidism
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4
Q

what is Paget’s disease?

A

causes an increased head size, thickening of skull bones, particularly frontal bone
headaches and hearing loss caused by impinging upon nerves exiting the skull

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5
Q

epidemiology of Paget’s disease

A

1-2% of Caucasians over 55
uncommon in people under 40
tends to occur in families (having a relative with Pagets makes you 7-10x more likely to develop it)

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6
Q

cause of Paget’s disease

A

unknown

potentially a slow acting virus

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7
Q

diagnosis of Paget’s disease

A

skull x-ray

mild elevation of serum alk phos

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8
Q

why is alk phos elevated in Pagets

A

produced by osteoblastic cells as they try to rebuild bone

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9
Q

treatment for Paget’s

A

bisphosphonates (induce apoptosis of osteoclasts)

calcitonin

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10
Q

common types of skull fractures

A

linear 69%
depression 11%
basilar 4%

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11
Q

result of depression fractures

A

inner table of bone often more extensively fractured than outer table
often cause extradural or epidural hemorrhage

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12
Q

describe the structure of a newborn’s skull

A

bones of a newborn’s calvaria are joined by dense connective tissue fibrous joints called sutures
softness of bones and looseness of sutures allow compression (molding) through the birth canal and rapid brain growth
small face, only unilamellar bone, no diploe, glabella, superciliary arches, or mastoid processes
styloid process has not fused to temporal bone yet

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13
Q

what is a fontanelle

A

sites of fibrous sutures where several bones meet

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14
Q

anterior fontanelle

A

future site of bregma (front part of hear)
junction of coronal and sagittal sutures
closes at 18-24 months

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15
Q

posterior fontanelle

A

future site of lamba
junction of sagittal and lamdoid sutures
closes at 9 months

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16
Q

premature suture/fontanelle closure

A

more concerning than a late closure

potential to limit CNS growth

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17
Q

what is craniosynostosis

A

premature closure of the sutures leads to deformities of the head which inhibit proper brain development

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18
Q

epidemiology of craniosynostosis

A

1 in 2000 births (75% males, 25% females)

part of a syndrome in 15-40% of patients, but usually isolated

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19
Q

risk factors and treatment of craniosynostosis

A

environmental factors can increase risk

surgical treatment generally required between 6-12 months or brain growth may be impaired

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20
Q

petrous part of temporal bone

A

wedge between sphenoid and occipital bones and encloses internal ear
dural sinuses sit on top

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21
Q

sella turcica

A

superior surface of body of sphenoid bone

forms hypophyseal fossa for the pituitary gland

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22
Q

sphenoid bone

A

body contains pituitary
lesser wing helps form the posterior edge of anterior cranial fossa
greater wing helps for floor of anterior edge of middle cranial fossa

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23
Q

palate expander

A

used to expand cartilaginous suture line (generally turns from cartilage to bone during puberty) between maxilla and palatine bones
only work if midline suture is cartilaginous

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24
Q

what are le Fort fractures

A

common patterns of facial fractures

most people survive unless CNS is affected

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25
Q

le fort I

A

separates maxillary teeth from rest of face

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26
Q

le fort II

A

separates upper teeth and nose from the rest of the face

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27
Q

le fort III

A

fracture through upper portion of the orbits, separating the face from the rest of the skull

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28
Q

5 layers of scalp

A
  1. skin
  2. connective tissue
  3. aponeurosis
  4. loose connective tissue
  5. periostium
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29
Q

connective tissue of scalp

A

highly vascular with blood vessels attached to the aponeurosis below

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30
Q

aponeurosis of scalp

A

dense connective tissue

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31
Q

loose connective tissue of scalp

A

layer upon which aponeurosis glides

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32
Q

periosteum of scalp

A

dense connective tissue attached to the bone with Sharpey’s fibers

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33
Q

what is the functional scalp

A

three outer layers of the scalp
skin
connective tissue
aponeurosis

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34
Q

discuss the structure of the functional scalp

A

dense connective tissue aponeurosis is continuous with the dense connective tissue surrounding the occipitalis posteriorly and the frontalis anteriorly
both muscles are derived from the second branchial arch and are supplied by cranial nerve VII

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35
Q

occipitalis muscle origin

A

superior nuchal line

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36
Q

scalping

A

can occur when hair is caught in machinery
3 outer layers (hair, skin, connective tissue, and epicranial aponeurosis) are pulled away as a unit and skull with periosteal connective tissue layer is left exposed
scalp can be reattached if bleeding is controlled

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37
Q

why might a patient die from scalping?

A

if knocked unconscious
arteries serving the scalp run in the connective tissue layer on top of the epicranial aponeurosis, tend to limit smooth muscle from contracting, allowing continued blood loss

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38
Q

“danger zone” of scalp

A

loose connective tissue

infection may easily spread within this zone and may also spread intracranially via emissary veins

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39
Q

what are emissary veins

A

connect the outside of the skull with the dural intracranial sinuses
normal blood flow from inside outward, but no valves so sometimes reverse

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40
Q

lacerations through epicranial aponeurosis

A

tend to gap widely due to pulling of the frontalis and occipitalis muscles
tend to bleed profusely due to lack of arterial contraction
direct pressure can usually stop it

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41
Q

surgical flaps on scalp

A

central region of forehead works well because it contains supratrochlear nerve, artery, and vein
can be used to reconstruct a nose

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42
Q

function of the CSF

A

mechanical and protective support for the brain
brain “weight” is 90% less in water than in air
ion sink for brain excitability

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43
Q

volume of CSF

A

total: 125-150 mL

75 mL surround the brain, 75 mL surrounds the spinal cord

44
Q

description of CSF

A

clear fluid
pink- bleed suspected
cloudy- bacterial or viral infection
pressure = 70-180 mm

45
Q

describe the production and movement of the CSF

A

60% is produced in the choroid plexuses within the lateral 3rd and 4th ventricles
passes the interventricular foramina into the 3rd ventricle
down the cerebral aqueduct of the fourth ventricle
out either the median aperture or the two lateral apertures

46
Q

subarachnoid cisterns

A

large subarachnoid space

47
Q

cerebellomedullary cistern

A

large subarachnoid space at the base of the skull

48
Q

absorption of CSF

A

absorbed back into venous blood through arachnoid villi along the superior sagittal sinus
some absorbed along the length of the spinal cord

49
Q

what is a spinal tap leak

A

sometimes after a spinal tap has been performed, CSF continues to leak at the site
under pathological conditions which increase intracranial pressure above the tentorium cerebelli (subdural hematoma) or decrease in pressure below tentorium cerebelli (CSF leak from spinal canal) the brain may herniate through the tentorial incisure

50
Q

what is an extracranial hematoma

A

goose egg

typically above galea, rarely below

51
Q

what is the pterion

A

junction of 4 bones: greater wing of sphenoid, frontal, parietal, and temporal bones
forms an H like structure

52
Q

what is special about the pterin

A

skull is particularly thin
frontal branch of the middle meningeal artery runs along the inner surface
causes an epidural hematoma if ruptured

53
Q

epidural hemorrhage

A

bleeding from a torn meningeal vessel may lead to an extradural accumulation of blood that can rapidly compress the brain, progressing to herniation or death if not evacuated

54
Q

what can cause an epidural hemorrhage

A

depression fracture of the skull

55
Q

extradural/epidural space

A

“potential” space superficial to dura matter

56
Q

subdural space

A

“potential” space between the dura and then fluid impermeable (membranous) layer of arachnoid

57
Q

subarachnoid space

A

real space filled with CSF

58
Q

how much CSF produced daily

A

500 ml

59
Q

list the layers of the meningeal coverings and spaces

A
skull
epidural potential space
dura matter
subdural potential space
arachnoid matter
subarachnoid space
pia matter
brain
60
Q

subdural hemorrhage

A

acute or chronic classifications
depends on the pressure of the vessel torn
most often in elderly people, cerebral veins are torn as the enter the superior sagittal sinus following head trauma

61
Q

cerebral vein tearing

A

blood leakage may be slow

62
Q

cerebral artery tearing

A

blood may spread quickly and over a large area (hemisphere) compressing the brain

63
Q

most frequent cause of subdural hemorrhage

A

tearing of the bridging veins between rain surface and dural sinus
can occur as the result of a relatively minor trauma

64
Q

those at greatest risk of subdural hemorrhage

A
children (thinner veins)
aged adults (longer bridging veins)
65
Q

subarachnoid hemorrhage

A

typically due to rupture of an aneurysm as arteries pass within the subarachnoid space
blood in CSF

66
Q

symptoms of subarachnoid hemorrhage

A
severe headache
stiff neck
loss of consciousness
often produced by hypertension and results in paralytic strokes
spinal tap = bloody
67
Q

principal sites of cerebral aneurysms

A

90% on anterior half of circle of Willis (from internal carotid arteries)
10% from posterior circulation off of vertebral arteries

68
Q

what are arachnoid granulations

A

hypertrophy of the arachnoid villi results in arachnoid granulations which may form pits on the inner table of cranial bones along the superior sagittal sinus

69
Q

function of arachnoid villi

A

site where cerebrospinal fluid returns to venous blood along the superior sagittal sinus

70
Q

2 pairs of arteries that supply brain blood

A
  1. internal carotid arteries

2. vertebral arteries

71
Q

branches of internal carotid arteries

A
ophthalmic arteries
anterior cerebral arteries
anterior communicating artery
middle cerebral arteries
posterior communicating arteries
72
Q

ophthalmic arteries

A

supply eye, orbit, and forehead

73
Q

anterior cerebral arteries

A

supply frontal lobes

74
Q

anterior communicating artery

A

between anterior cerebral arteries

75
Q

middle cerebral arteries

A

supply temporal lobes

76
Q

posterior communicating arteries

A

join posterior cerebral arteries

77
Q

vertebral arteries

A

pierce the atlantooccipital membrane and dura matter, enter into the subarachnoid space, pass up through the foramen magnum and unite to form a single basilar artery which runs up along the clivus of the occipital bone

78
Q

branches of vertebral arteries

A
posterior inferior cerebellar arteries
anterior inferior cerebellar arteries
superior cerebellar arteries
posterior cerebral arteries
posterior communicating arteries
79
Q

posterior cerebral arteries

A

supplies occipital and temporal lobes

80
Q

3 types of headaches

A
  1. vascular
  2. muscular contraction
  3. traction and inflammatory types
81
Q

sinusitis

A

inflammation of one or more of the paranasal sinuses, but usually refers to bacterial infection of the sinuses, secondary viral infections or allergic rhinits

82
Q

acute sinusitis

A

starts w cold-like symptoms
runny, stuffy nose and facial fain
may start suddenly and last 2-4 weeks

83
Q

subacute sinus inflammation

A

4-12 weeks

84
Q

chronic sinusitis

A

12 weeks or longer

85
Q

function of nasal cilia

A

extremely important in clearing nose, particularly in posterior 2/3 of nasal cavity

86
Q

basal movement of mucous

A

posteriorly towards nasopharynx and is most pronounced over middle and inferior conchae

87
Q

what can adversely affect nasal cilia

A

heat, cold, dryness, and drugs

secondary infections much more likely if cilia don’t function

88
Q

deviated nasal septum

A

occurs in 30% of adults

midline structure of nose frequently deviates to one side or the other

89
Q

severe deviation of nasal septum

A

may occlude a nasal fossa, preventing adequate drainage of nose and sinuses
interferes with flow of air on one side

90
Q

what is anosmia

A

loss of sense of smell

91
Q

what can cause anosmia

A

head trauma may result in shearing of the olfactory nerves as they pass through the cribriform plate
may be early sign of a degenerative brain disease (Parkinson’s or alzheimer’s)

92
Q

nasal arteries supplying Keisselbach’s area

A

anterior ethmoid artery
sphenopalatine artery
greater palatine artery
superior labial artery

93
Q

which nasal arteries can be manually compressed

A

greater palatine artery

superior labial artery

94
Q

epistaxis

A

nosebleed
frequent site is at Kiesselbach’s area
dry air and nose picking may contribute
can be arterial or venous

95
Q

what is Kiesselbach’s area and why is it susceptible to nosebleeds

A

4 names arteries (as discussed above) participate in the formation of a rather superficial anastomotic network on the nasal septum just posterior to the vestibular area

96
Q

what to do for a nosebleed from kiesselbachs plexus

A

apply pressure on upper lip and hard palate behind incisors cutting off blood from septal branch of the superior labial artery and branches from the greater palatine artery that pass through the incisive formen

97
Q

discuss the anesthetic process from a broken nose

A
  1. topical anesthetic applied to nasal mucosa
  2. anesthetic injected at bridge of nose bilaterally to block branches of anterior ethmoidal nerves
  3. needle inserted via nasal vestibule to reach infraorbital nerves
98
Q

clinical tidbits about toddler’s tendency to stick things up their noses

A

conchae and meatuses provide excellent sites for lodging of foreign objects and may make them difficult to detect

99
Q

sphenoid sinus pain

A

referred to top of head

100
Q

ethmoid sinus pain

A

referred to medial and/or lateral to the eyes

101
Q

frontal and maxillary sinus pain

A

generally caused by tapping on bone superficial to the sinus

102
Q

frontal sinus location and drainage

A
location= under middle turbinate
drainage= infundibulum /frontonasal duct
103
Q

anterior ethmoid sinus location and drainage

A
location = under middle turbinate
drainage = hiatus semilunaris
104
Q

middle ethmoid sinus location and drainage

A
location = under middle turbinate
drainage = ostia of ethmoid bulla
105
Q

posterior ethmoid sinus location and drainage

A
location= under superior turbinate
drainage = ostia of posterior ethmoid air cells
106
Q

sphenoid sinus location and drainage

A
location = sphenoethmoidal recess
drainage = sphenoid ostium
107
Q

maxillary sinus location and drainage

A
location = under middle turbinate
drainage = maxillary ostium in hiatus semilunaris