Skull and cervical spine anatomy and imaging

Question 1

what is the skull and what does it house?

Answer 1

skull is the bony skeleton of the head which houses the brain, organs of special sense as well as upper parts of resp and GI system

Question 2

what is the only moveable joint in the skull

Answer 2

temporomadibuluar joint

Question 3

what is the function of the skull

Answer 3

• protects brain, brianstem, vasculature and cranial nerves
• provides attachments for muscles
• gives us our identity

Question 4

what are pneumatised bones and why do we have them

Answer 4

bones with air spaces such as frontal, temporal, sphenoid and ethmoid

• reduce weight
• add resonance to our voice (hence why when you have sinusitis, your voice changes)

Question 5

name the two divisions of the skull and what they consist of

Answer 5

neurocranium - bony case of the brain including cranial meninges with roof (calvaria/skull cap) and a floor (cranial base/basicranium)

viscerocranium - ant part of cranium consisting of bones surronding the oral cavity, nasal cavity and most of orbit

Question 6

identify the bones of the neurocranium

Answer 6

8 bones (4 single and 2 paired)

look at slide 9

Question 7

identify the bones of the viscerocranium

Answer 7

15 bones (3 single and 6 paired)

look at slides 10+11

Question 8

identify the external acoustic meatus

Answer 8

look at slide 12

at the end of this is the ear drum

Question 9

state the boundaries of the temporal fossa

Answer 9

superior and posterior = sup and inf temporal lines
anterior = zygomatic process of frontal bone and frontal process of zygomatic bone
inferior = infratemporal crest deep to zygomatic arch
floor = includes pterion

Question 10

Where is the pterion located and why is it of clinical significance?

Answer 10

• H-shaped junction of sutures
• 4cm sup to midpoint of zygomatic arch and 3cm posterior to frontal process of zygomatic bone
• frontal, parietal, temporal + greater wing of sphenoid bones
• structurally weak (thin) area of the skull therefor vulnerable to injury
• overlies ant branch of middle meningeal artery
• injury could cause epidural/extradural haematoma

Question 11

what is the calvaria and what is it composed of?

Answer 11

= skull cap

2x parietal, 1x frontal, 1x occipital

Question 12

which sutures fuse the calvaria and point out the bregma and lambda

Answer 12

• coronal, sagittal + lambdoid sutures
• junction between coronal and sagittal = bregma
• junction between sagittal and lambdoid = lambda

Question 13

identify the layers of the calvaria

Answer 13

outer cortical (compact) bone - ext and internal
separated by diploe (spongy/cancellous) bone

Question 14

where is the granular foveolae and whats its fucntion?

Answer 14

inferior side of pareital bone

arachnoid granulations which return CSF to the venous circulation

Question 15

what are small islands of bone within a cranial suture known as and where are they commonly observed?

Answer 15

sutural, accessory or Wormian bones

most common in lambdoid sutures

Question 16

what type of joint are sutures

Answer 16

structurally = fibrous joint 
functionally = synarthrosis (limited or no movement)

Question 17

what is the function of fontanelles?

Answer 17

• moulding of cranial shape during birth

- allow post-natal growth of brain

Question 18

identify the supra-orbital notch/foramen and state what goes through it?

Answer 18

1st br of trigeminal nerve (CN V) - opthalmic

Question 19

identify the infraorbital foramen and state what goes through it?

Answer 19

2nd br of trigeminal nerve (CN V) - maxillary

Question 20

identify the mental foramen and state what goes through it?

Answer 20

3rd br of trigeminal nerve (CN V) - mandibular

Question 21

what clinical signs can be observed through the anterior fontanelles

Answer 21

deep ant fontanelle = dehydration

bulging = increased intracranial pressure

Question 22

identify the superior orbital fissure and state what goes through it?

Answer 22

trochlear nerve*
oculomotor nerve* 
abducens nerve*
lacrimal nerve 
frontal nerve 
nosociliar nerve
superior ophthalmic vein 
Lacrimal artery 

• for eye muscles

Question 23

identify the inferior orbital fissure and state what goes through it?

Answer 23

zygomatic branch of maxillary nerve
inferior ophthalmic vein
infraorbital nerve
sympathetic nerves

Question 24

what is the chona?

Answer 24

pos opening of nasal cavity

separated by vomer

Question 25

``` identify and state what goes through: carotid canal jugular foramen foramen magnum hypoglossal canal foramen spinosum foramen ovale ```

Answer 25

carotid canal = internal carotid ar jugular foramen = int jugular vein, CN 9,10,11 foramen magnum = brain stem -> spinal cord + vertebral arteries hypoglossal canal = hypoglassal nerve (CN XII) foramen spinosum = middle meningeal artery foramen ovale = 3rd br of trigeminal (mandibular)

Question 26

boundaries of infratemporal fossa

Answer 26

``` lat = ramus of mandible med = lat pterygoid plate of sphenoid sup = infratemporal crest inf = angle of mandible ant = pos aspect of maxillae pos = tympanic plate, mastoid and styloid process ```

Question 27

what connects pterygopalatine fossa to the: - orbit - infratemporal fossa - nasal cavity - middle cranial fossa - nasopharynx - base of skull - oral cavity

Answer 27

``` orbit = inf orbital fissure infratemporal fossa = pterygomaxillary fissure nasal cavity = sphenopalatine foramen middle cranial fossa = foramen rotundum nasopharynx = pharyngeal canal base fo skull = vidian canal oral cavity = pterygopalatine canal ```

Question 28

What are the contents of the pterygopalatine fossa

Answer 28

- pterygopalatine ganglion - V2 (infraorbital and zygomatic) - nerve of pterygoid canal (Vidi) - PS and sensory (taste) fibres of the facial nerve - symp fibres from int carotifd plexus

Question 29

which bones make up the ant cranial fossa and what occupies it?

Answer 29

frontal, ethmoid and sphenoid bones | occupied by the frontal lobes

Question 30

what structure within the ant fossa allows the olfactory bulb to receive its nerve fibres from the nasal cavity?

Answer 30

foramina of the cribiform plate cribiform plate fractures can present with CSF rhinorrhoea

Question 31

which bones make up the middle cranial fossa and what occupies it?

Answer 31

sphenoid and temporal occupied by the temporal lobes

Question 32

where does the pituitary gland lie and what is it surrounded by and what does this mean for a tumour growing there

Answer 32

hypophyseal (pituitary) fossa surrounded by 4 clinoid processes and 2 sup projections (dorsum sellae pos, tuberculum sellae ant) therefore if there a tumour here it will grow superiorly hitting the optic chiasm so first symptoms might be visual disturbances

Question 33

what bones make up the pos cranial fossa and what is it occupied by?

Answer 33

sphenoid, occipital and temporal | occupied by cerebellum and brainstem

Question 34

what is the importance of the clivus

Answer 34

its where the brainstem lies

Question 35

what two structures join to form the TMJ? what type of joint is it? where is dislocation most common? what separates the sup and inf articular cavities

Answer 35

glenoid (mandibular) fossa of temporal bone + condylar process of mandible modified hinge (atypical) synovial joint ant dislocation into the infratemporal fossa most common fibrocartilangenous articular disk

Question 36

what are the ligaments of the TMJ and whats their functions

Answer 36

2 extrinsic - sphenomandibular lig (primary passive support of the mandible) - stylomandibular lig 1 intrinsic - lateral lig (strengthens TMJ laterally and prevents pos dislocation)

Question 37

when is the TMJ most unstable

Answer 37

during depression as the condylar process moves anteriorly being vulnerable to ant dislocation