Internal carotid artery

Internal carotid artery


INTERNAL CAROTID ARTERY

  • On angiogram internal carotid show ‘S’ shaped figure (carotid siphon).
  • The internal carotid artery is a major paired artery, one on each side of the head and neck.
  • They arise from the common carotid arteries where these bifurcate into the internal and external carotid arteries at cervical vertebral level 3 or 4 .
  • Internal carotid artery at the bifurcation from the common carotid is Lateral to the external carotid.
  • The internal carotid artery supplies the brain, while the external carotid nourishes other portions of the head, such as face, scalp, skull, and meninges.
  • Supplies duramater 
  • Internal carotid artery lies in close relation of the optic nerve. 
BRANCHES:
  • Cervical part in the neck
  • Petrous part in the petrous temporal bone
  • Cavernous part in the cavernous sinus
  • Cerebral part in relation to base of brain

COURSE:

1. Cervical Part:

  • It ascends vertically in the neck from its origin to the base of skull to reach the lower end of the carotid canal.
  • This part is enclosed in carotid sheath along with internal jugular and vagus nerve. 
  • No branches arises from the internal carotid artery in the neck.
  • Its initial part shows slight dilation, carotid sinus, which acts as a baroreceptor.
2. Petrous Part
  • Within the petrous part of the temporal bone,in the carotid canal runs upward forward & medially at rt. Angle.

Branches:

  1. Caroticotympanic– enter middle ear & anastomose with ant. & post. Tympanic branches
  2. Artery of the Pterygoid Canal–  anastomose with greater palatine artery

3. Cavernous Part

  • Within the Cavernous Sinus

Branches:

  1. Cavernous branch
  2. Superior & inferior Hypophyseal artery
  3. Meningeal branch

4. Cerebral Part-

  • Lies at the base of the brain after emerging from the cavernous sinus.
  • Largest

Branches:

  1. Ophthalmic Artery
  2. Anterior Cerebral Artery
  3. Middle Cerebral Artery
  4. Posterior Communicating Artery
  5. Anterior choroidal Artery
OPHTHALMIC ARTERY: 
  • Branch from cerebral part of ICA.
  • It enters orbit through optic canal lying inferolateral to optic nerve.
  • Both artery & nerve lie in a common dural sheath.
  • It gives following branches:
 1. Central artery of retina →an end artery
 
2. Lacrimal artery: It gives following branches-
  1. Lateral palpebral branch
  2. Zygomaticotenporal
  3. Zygomaticofacial 
  4. Recurrent meningeal
  5. Meningeal
  6. Ciliary
  7. Anterior ethmoidal → Supplies anterior ethmoidal sinus
  8. Posterior ethmoidal
  9. Medial palpebral
  10. Supratrochlear
  11. Supraorbital
  12. Dorsal nasal
Exam Question
 
  • Internal carotid artery Supplies duramater.
  • Internal carotid artery lies in close relation of the optic nerve.
  • Internal carotid artery at the bifurcation from the common carotid is Lateral to the external carotid
  • Cavernous part of ICA runs through the medial wall of cavernous sinus.
  • Internal carotid artery crosses Cavernous sinus.
 BRANCHES:

1. Cervical Part:

  • It ascends vertically in the neck from its origin to the base of skull to reach the lower end of the carotid canal.
  • This part is enclosed in carotid sheath along with internal jugular and vagus nerve. 
  • No branches arises from the internal carotid artery in the neck.
  • Its initial part shows slight dilation, carotid sinus, which acts as a baroreceptor.
2. Petrous Part
 
  • Within the petrous part of the temporal bone,in the carotid canal runs upward forward & medially at rt. Angle.
  • Branches:
  1. Caroticotympanic- enter middle ear & anastomose with ant. & post. Tympanic branches
  2. Artery of the Pterygoid Canal-  anastomose with greater palatine artery

3. Cavernous Part

  • Within the Cavernous Sinus
  • Branches:
  1. Cavernous branch
  2. Superior & inferior Hypophyseal artery
  3. Meningeal branch

4. Cerebral Part-

  • Lies at the base of the brain after emerging from the cavernous sinus.
  • Largest
  • Branches:
  1. Ophthalmic Artery
  2. Anterior Cerebral Artery
  3. Middle Cerebral Artery
  4. Posterior Communicating Artery
  5. Anterior choroidal Artery
Don’t Forget to Solve all the previous Year Question asked on Internal carotid artery

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