Internal Carotid Artery

Question 1

Origin

Answer 1

1. From CCA at thyroid cartilage upper border (disc between C3 and C4)
2. At its beginning, it shows localized dilatation (carotid sinus)

Question 2

Termination

Answer 2

At brain base dividing into anterior and middle cerebral arteries

Question 3

Parts

Answer 3

4 parts:
1. Cervical
2. Petrous
3. Cavernous
4. Cerebral

Question 4

Cervical part course

Answer 4

In neck inside carotid sheath medial to IJV and vagus nerve:
Superficially:
1. ECA with structures superficial and deep to it
Deep:
1. Pharynx wall
2. Ascending pharyngeal artery
3. Superior laryngeal nerve
4. Sympathetic chain
Skull base:
ICA lies anterior to IJV with Lee 4 cranial nerves in between

Question 5

Petrous part course

Answer 5

1. Inside petrous bone (carotid canal
2. Running upwards then forwards and medial
3. Leaving it to enter cavernous sinus through foramen lacerum on cartilage which close it

Question 6

Petrous part branches

Answer 6

1. Caroticotympanic: to tympanic cavity
2. Artery of pterygoid canal: to pharynx

Question 7

Cavernous part course

Answer 7

1. Inside cavernous sinus running sinuous course upwards the forwards and finally upwards
2. Leaves the roof

Question 8

Cavernous part relations

Answer 8

Inferolateral:
1. Abducent nerve
2. Sphenoid body
Medial:
1. Sphenoidal air sinus

Question 9

Cavernous part branches

Answer 9

Inferior hypophyseal artery: to pituitary posterior lobe

Question 10

Cerebral part course

Answer 10

1. Leaves sinus roof
2. Artery passes backwards for 1 cm then upwards
3. Ends at brain base below anterior perforated substance
   Dividing into 2 terminals

Question 11

Cerebral part branches

Answer 11

1. Ophthalmic artery
2. Posterior communicating artery
3. Anterior choroidal artery
4. Anterior cerebral artery
5. Middle cerebral artery

Question 12

ICA intracranial part

Answer 12

1. Petrous part
2. Cavernous part
3. Cerebral part
   Show 6 bends to damp any sudden rise of pressure inside it