Anastamoses between internal and external carotid arteries

Multiple, highly-variable anastamoses exist between the internal and external carotid arteries. These anastamoses may not be evident on non-invasive imaging or even catheter angiography, and may only be demonstrable with elevated intra-arterial pressures or high-flow states. ICA-ECA collaterals may enlarge following occlusion of the ICA and have been implicated in the development of dural AV fistulas.

A non-exhaustive list of sites include:

  • Orbit
  • Cavernous sinus
    • Inferolateral trunk (ICA) – branches of maxillary artery (ECA)
    • The inferolateral trunk is a variably identified branch of the cavernous (C4) segment of the ICA. Branches of the inferolateral trunk may anastamose with the middle meningeal artery/deep temporal artery/artery of the foramen rotundum
  • Ethmoidal sinuses
  • Nose
    • Dorsal nasal artery (ICA) – nasal branches of the facial artery (ECA)
    • Dorsal nasal artery is branch of the ophthalmic artery
    • Recognition is important in epistaxis embolization
  • Scalp

Collateral pathways are also present between the occipital artery (from the ECA) and muscular branches of the vertebral arteries around the C1 and C2 vertebrae.


See also

Article information

rID: 87207
Section: Anatomy
Synonyms or Alternate Spellings:
  • ICA-ECA anastamoses; ICA-ECA collaterals; internal-external carotid artery anastamoses

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