skull anatomy

Question 1

how many bones does the skull have?

Answer 1

22

Question 2

how are the skulls of the bone divided?

Answer 2

neurocranium

viscerocranium

Question 3

how many bones of the skull are linked by fibrous joints?

Answer 3

21

Question 4

what is the only non-fibrous joint of the skull?

Answer 4

synovial temporomandibular joint

Question 5

what is the function of the neurocranium?

Answer 5

housing the brain

attachment site for the head and neck muscles

Question 6

what is the function of the viscerocranium?

Answer 6

• Form framework of the face – makes up orbit, nasal cavity and oral cavity
• Contain cavities for special sense organs (sight, taste and smell)
• Opening for air and food passage
• Secure teeth
• Anchor facial muscles of expression

Question 7

how many cranial bones are there?

Answer 7

8

Question 8

name all the cranial bones

Answer 8

o 2x parietal, 2x temporal, sphenoid, frontal, ethmoid, occipital

Question 9

how does the frontal bone change throughout development?

Answer 9

starts as 2 in development and then they fuse

Question 10

what does a fracture of the ethmoid bone lead to?

Answer 10

CSF leaking into the nose

Question 11

what is the function of sutures

Answer 11

limit movement of the bones

Question 12

what bone predominantly makes up the zygomatic arch?

Answer 12

temporal bone

Question 13

where is the external acoustic meatus found?

Answer 13

outside the temporal bone

Question 14

what does the temporal bone house?

Answer 14

the middle and internal ear

Question 15

what houses the internal ear?

Answer 15

petrous part of the temporal bone

Question 16

what does the sphenoid bone link?

Answer 16

facial skeleton to cranial skeleton

Question 17

how many pterygoid plates does the sphenoid bone have and what do they do?

Answer 17

4

attachment point for pterygoid muscles (muscles of mastication)

Question 18

what is the sella turcica?

Answer 18

bony cradle which protects the pituitary gland

Question 19

what is the function of the clinoid processes?

Answer 19

attachment points for the dura mater in the skull

Question 20

what are the 3 layers of the meninges?

Answer 20

dura mater
arachnoid mater
pia mater

Question 21

what are the two layers of dura mater in the skull?

Answer 21

meningeal

periosteal

Question 22

where is the periosteal layer found?

Answer 22

sticks to the inner layer of the skull

Question 23

how are inward folds of the dura mater made?

Answer 23

when the meningeal layer of the dura mater pulls away from the periosteal layer

Question 24

name the inward folds of the meningeal layer of dura mater

Answer 24

falx cerebri

tentorium cerebelli

Question 25

what does the falx cerebri do?

Answer 25

separates the left and right hemisphere

Question 26

what does the tentorium cerebelli do?

Answer 26

separates the cerebellum from the cerebrum

Question 27

what is the function of the inward folds of the meningeal layer?

Answer 27

help compartmentalise the inside of the skull and gives support to the brain

Question 28

what is the tentorial notch?

Answer 28

hole in the tentorium cerebelli to allow brainstem to pass up to the cerebrum

Question 29

what are the dural venous sinuses?

Answer 29

a network of endothelial lines spaces which are filled with venous blood in the space between dura mater layers

Question 30

where is the superior saggital sinus?

Answer 30

at the top of the falx cerebri

Question 31

where is the inferior saggital sinus?

Answer 31

bottom of the falx cerebri

Question 32

what does the straight sinus do?

Answer 32

joins the supeiror and inferior saggital sinus

Question 33

what leads into the transverse sinus?

Answer 33

the straight sinus

Question 34

where does the sigmoid sinus leave the skull?

Answer 34

through the jugular foramen into the jugular vein

Question 35

where are the cavernous sinuses found?

Answer 35

either side of the pituitary gland

Question 36

what runs through the cavernous sinus?

Answer 36

internal carotid artery and some cranial nerves

Question 37

what do the petrosal sinuses do?

Answer 37

link cavernous sinus to sigmoid and transverse sinuses

Question 38

what part of the skull do the facial bones form?

Answer 38

anterior skull – make up orbit, oral and nasal cavity

Question 39

what are the orbits?

Answer 39

Bilateral pyramidal shaped cavity on the anterior aspect of the skull

Question 40

what is the function of the orbit?

Answer 40

the eyeball, extra-ocular muscles and associated neurovasculature

Question 41

what bones make up the orbit and what aspect of the orbit do they make up?

Answer 41

frontal (superior), maxilla (inferior), lacrimal, ethmoid (medial), sphenoid, zygomatic (lateral)

Question 42

which walls of the orbit are thin?

Answer 42

medial and inferior walls

Question 43

what part of the orbit is most likely to fracture?

Answer 43

medial and inferior walls

Question 44

what makes up the hard palate?

Answer 44

maxilla anteriorly and palatine bone posteriorly

Question 45

what makes up the nasal septum?

Answer 45

bony and cartilaginous contributions

Question 46

what is either side of the crista galli?

Answer 46

cribiform plate

Question 47

which of the conchae are from the ethmoid bone?

Answer 47

superior and middle

Question 48

which of the conchae are their own bone?

Answer 48

inferior conchae

Question 49

what are the paranasal sinuses?

Answer 49

Hollow spaces within the frontal, sphenoid, ethmoid and maxillary bones

Question 50

what lines the paranasal sinuses?

Answer 50

mucous membrane

Question 51

where do all the paranasal sinuses drain?

Answer 51

the nose

Question 52

where is the frontal sinus?

Answer 52

in the frontal bone

Question 53

which is the largest sinus?

Answer 53

maxillary sinus

Question 54

explain the drainage in the maxillary sinus

Answer 54

Drains into the middle meatus so it has to be full of mucus before it drains

Question 55

where is the sphenoid sinus?

Answer 55

behind the nasal cavity

Question 56

what makes up the ethmoid sinus?

Answer 56

many small sinuses

Question 57

which bones are most and least developed in the foetal skull?

Answer 57

cranial bones are most developed | facial skeleton is underdeveloped and small - jaw is small and no teeth

Question 58

do newborns have sinuses?

Answer 58

no

Question 59

what are fontanelle?

Answer 59

large spaces between bones where sutures havent formed yet in newborns

Question 60

what is the largest fontanelle?

Answer 60

anterior

Question 61

how do dehydrated babies present?

Answer 61

depressed anterior fontanelle

Question 62

how does a raised intercranial pressure in a baby present?

Answer 62

fontanelle bulges

Question 63

when does the anterior fontanelle close?

Answer 63

18 months

Question 64

when does the posterior fontanelle close?

Answer 64

12 months

Question 65

what is the function of the fontanelles?

Answer 65

allows brain to grow; allows baby to be born without skull fracture

Question 66

what separates the anterior and middle cranial fossa?

Answer 66

the lesser wing of the sphenoid

Question 67

what separates the middle and posterior cranial fossa?

Answer 67

petrous part of the temporal bone

Question 68

what does the anterior cranial fossa protect?

Answer 68

the frontal lobes of the brain

Question 69

what does the middle cranial fossa protect?

Answer 69

temporal lobes

Question 70

what sits in the posterior cranial fossa?

Answer 70

cerebellum

Question 71

what passes through the foramen spinosum?

Answer 71

middle meningeal artery | runs into the skull then underneath the pterion

Question 72

what artery runs under the pterion?

Answer 72

middle meningeal artery

Question 73

what passes through the jugular foramen?

Answer 73

internal jugular vein

Question 74

describe the passage of the internal carotid artery

Answer 74

travels through the carotid canal through temporal bone to the foramen lacerum then travels superiorly

Question 75

what is the foramen lacerum?

Answer 75

covered over in cartilage, so nothing passes through this

Question 76

what is the weakest point in the skull?

Answer 76

pterion

Question 77

what complication arises if the pterion is fractured?

Answer 77

laceration to middle meningeal artery leading to an extradural haematoma

Question 78

what bones make up the pterion?

Answer 78

parietal bone, squamous part of the temporal bone, the greater wing of sphenoid and the frontal bone

Question 79

how many cranial nerves are there?

Answer 79

12

Question 80

where does the olfactory nerve run?

Answer 80

inferiorly from the olfactory bulb, through perforated cribiform plate of the ethmoid bone to enter the nasal cavity

Question 81

where does the optic nerve run?

Answer 81

Optic nerve transverses the optic canal to enter the orbit

Question 82

where does the occulomotor nerve come from?

Answer 82

the midbrain

Question 83

where does the trochlear nerve come from?

Answer 83

posterior surface of the midbrain

Question 84

where does the abducens nerve come from?

Answer 84

pons

Question 85

where do the occulomotor, trochlear and abducens transverse?

Answer 85

the superior orbital fissure to enter the orbit

Question 86

where does the trigeminal nerve emerge from?

Answer 86

lateral surface of the pons

Question 87

what are the branches of the trigeminal nerve?

Answer 87

ophthalmic, maxillary and mandibular

Question 88

where does the opthalmic branch transverse?

Answer 88

superior orbital fissure to enter the orbit

Question 89

how does the maxillary branch of the trigeminal nerve leave the cranium?

Answer 89

through the foramen rotundum

Question 90

how does the mandibular branch leave the cranium?

Answer 90

through foramen ovale

Question 91

where does the facial nerve emerge from?

Answer 91

the pons

Question 92

where does the facial nerve travel?

Answer 92

into internal acoustic meatus – inside temporal bone Leaves temporal bone through stylomastoid foramen (on the base of the skull) Emerges from the pons

Question 93

where does the vestibulocochlear nerve travel?

Answer 93

emerges from the pons and enters the internal acoustic meatus

Question 94

where do the glossopharyngeal and vagus travel?

Answer 94

* Glossopharyngeal nerve emerges from lateral surface of medulla oblongata w vagus * Both exit skull via jugular foramen

Question 95

where does the spinal accessory nerve travel from?

Answer 95

first 5-6 cervical spinal nerves

Question 96

describe the passage of the spinal accessory nerve?

Answer 96

* Emerges from the first 5-6 cervical spinal nerves * Then runs superiorly through foramen magnum alongside the brainstem * Leaves skull via jugular foramen

Question 97

what does the spinal accessory nerve innervate?

Answer 97

sternocleidomastoid | trapezius

Question 98

where does the hypoglossal nerve emerge from?

Answer 98

anterior aspect of the medulla oblongata

Question 99

where does the hypoglossal nerve run?

Answer 99

through the hypoglossal canal