Clinical anatomy of interior skull

Question 1

Where is an area of bone weakness on the skull due to thin bone?

Answer 1

Pterion

Question 2

Which borns join to form pterion?

Answer 2

Frontal, temporal, parietal, sphenoid

Question 3

Where are areas of weakness on the skull due to openings?

Answer 3

Nasal apertures and orbit

Question 4

Why does the structure of sutures make them immovable?

Answer 4

Joined by very strong collagen fibres

Question 5

How does interdigitation make sutures stronger?

Answer 5

Increases SA of contact

Question 6

What is bevelling and what is the effect of bevelling on sutures?

Answer 6

Overlapping of bone, makes the suture stronger

Question 7

What is buttressing?

Answer 7

Thickened areas of bone that support fragile zones like the nasal cavity and orbit

Question 8

Buttressing of the skull is in line with forces of mastication, why is this?

Answer 8

Dissipate forces of mastication so maxillary teeth don’t get forced into maxillary sinus

Question 9

Name the buttresses on the anterior surface of face?

Answer 9

Supracilary bar, lower orbital margin, canine buttress, maxilla-zygomatic buttress

Question 10

What type of forces does the buttressing not he anterior surface fo the face not resist?

Answer 10

Anterior

Question 11

What buttressing does resist anterior forces?

Answer 11

Tuberosity pterygoid buttress

Question 12

How do the dural reflections have a protective role?

Answer 12

Transmit weight to skull and absorb energy of impact

Question 13

What allows the dural reflections to absorb energy of impact?

Answer 13

They are incompressible and flexible

Question 14

Through what fo. do the venous sinuses drain blood?

Answer 14

Jugular fo.

Question 15

What are the 3 protective roles of venous insulin drainage?

Answer 15

Drain 70% of blood through jugular fo.
Cooling mechanism
Protect abasing changes in BP by moving blood to emissary veins

Question 16

What is the extradural space?

Answer 16

Between duramater and skull

Question 17

What occurs during an extradural haemorrhage?

Answer 17

Blood strips dura away from skull and presses against brain

Question 18

What artery does an extradural haemorrhage effect?

Answer 18

Middle meningeal

Question 19

During a subdural haemorrhage where does blood drain into?

Answer 19

Superior cerebral vein

Question 20

What is the subarachnoid space normally filled with?

Answer 20

CSF

Question 21

What are the routes of infection spread?

Answer 21

Tissue plane, venous, lymphatics, direct erosion

Question 22

If an infection is untreated it can?

Answer 22

Cause airway obstruction
Spread into brain
Cause septicaemia

Question 23

What is the line of least erosion?

Answer 23

Spread through the tissue before thick - may spread in an unexpected way

Question 24

During a periodical abbess the route of infection is determined by line of least residence, this changes in individuals deepening on the thickness of which bone?

Answer 24

Alveolar bone

Question 25

Name the tissue spaces of the lower jaw

Answer 25

``` Sublingual Submandibular Submental Pteyrgomandibular Peritonsillar Retropharyngeal ```

Question 26

Name the tissue spaces of the upper jaw

Answer 26

Parotid Canine Palatal Infratemporal

Question 27

If an infection spreads intraorally, which tissue plane does it infect?

Answer 27

Sublingual

Question 28

If an infection spreads extra orally which tissue plane doe sit infect?

Answer 28

Submandibular

Question 29

If an infection spreads to the neck which space does it infect?

Answer 29

Retropharyngeal

Question 30

Paranasal sinuses are in direct contact with bone, how can infection spread from here?

Answer 30

Rapid erosion

Question 31

Ludwigs angina can occur after a tooth infection. What is it?

Answer 31

Infection spread backwards towards posterior border of mylohyoid and infects mylohyoid, causes growth an pushes tongue pack to block airway

Question 32

Why is cavernous sinus thrombosis an issue?

Answer 32

Cavernous sinus is deep seated so antibiotics cannot reach

Question 33

Cavernous sinus thrombosis blocks what artery?

Answer 33

Internal carotid