Skull and foramens

Question 1

What foramen transmits the middle meningeal artery?

Answer 1

foramen spinosum

Question 2

What cranial bones does the foramen spinosum lie in?

Answer 2

sphenoid bone

Question 3

Describe the route of ICA from neck to cavernous sinus

Answer 3

(1. ) ICA enters via carotid foramen from the inferior aspect of the skull
(2. ) It passes through the carotid canal located within the petrous part of the temporal bone
(3. ) ICA enters the cranium just before the foramen lacerum ICA does not pass through the FL
(4. ) The ICA then enters the cavernous sinus

Question 4

What causes RICP and 5 signs associated with it?

Answer 4

(1. ) Caused by space occupying lesions or idiopathic intracranial HTN
(2. ) Sx = headache, nausea, visual disturbances, altered consciousness, papilloedema

Question 5

What structures separate the anterior, middle, posterior cranial fossa?

Answer 5

(1. ) Lesser wing of the sphenoid seperates the anterior and middle cranial fossa
(2. ) Petrous part of temporal bone separates the middle and posterior cranial fossa

Question 6

What structures are found in the anterior cranial fossa?

Answer 6

(1. ) Contains the frontal lobe
(2. ) Structures:
- Orbital part of frontal
- cribriform plate of ethmoid
- lesser wings of sphenoid.
- Cristae galli = attachment for falx cerebri

Question 7

What structures are found in the middle cranial fossa?

Answer 7

(1. ) Contains the temporal lobe and pituitary gland
(2. ) Foramen:
- Optic canal = CN2, opthalamic artery
- Superior orbital fissure = CN3, 4, V1, 6
- Foramen rotundum = CNV2
- Foramen ovale = CNV3
- Foramen spinosum = middle meningeal artery
- Foramen laecrum
- Carotid groove

(3. ) Other structures
- sella turnica = bounded by dorsum sellae, where pituitary gland sits

Question 8

What structures are found in the posterior cranial fossa?

Answer 8

(1. ) Contains the brainstem and cerebellar
(2. ) Foramen:
- Foramen magnum
- Internal acoustic meatus
- Jugular foramen
- Hypoglossal canal

(3. ) Depressions:
- internal occipital protuberance = confluence of sinuses
- ‘S-shaped’ groove for Sigmoid Sinus along the petrous edge going into the jugular foramen
- Groove for transverse sinus

Question 9

Foramen for all 12 CNs, IJV, ICA, vertebral a.

Answer 9

(1. ) Cribriform plate = CN1
(2. ) Optic Canal = CN2
(3. ) SOF = CN3, 4, 6, V1
(4. ) FR = CNV2
(5. ) FO = CNV3
(6. ) Internal acoustic meatus = CN7, 8
(7. ) Jugular foramen = CN9, 10, 11
(8. ) Hypoglossal Canal = CN12

(9. ) Sigmoid sinus becomes IJV and leaves skull at the jugular foramen
(10. ) ICA enter carotid foramen and canal and enter skull
(11. ) Vertebral a. enters into skull via foramen magnum