Anastamoses between internal and external carotid arteries

Last revised by Dr Daniel J Bell ◉ on 03 May 2022

Citation, DOI & article data

Citation:

Harvey, J., Bell, D. Anastamoses between internal and external carotid arteries. Reference article, Radiopaedia.org. (accessed on 22 May 2022) https://doi.org/10.53347/rID-87207

DOI:

https://doi.org/10.53347/rID-87207

Permalink:

https://radiopaedia.org/articles/87207

rID:

87207

Article created:

23 Feb 2021 by Dr James Harvey

Revisions:

10 times by 4 users - see full revision history

System:

Vascular, Central Nervous System

Section:

Anatomy

Tag:

ica-eca collaterals; internal carotid artery anastamoses; collaterals blood supply;

Synonyms:

Internal-external carotid artery anastomoses
ICA-ECA collaterals
ICA-ECA anastomoses

Multiple, highly-variable anastomoses exist between the internal and external carotid arteries. These anastomoses 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.

Internal carotid artery - external carotid artery (ICA-ECA) collaterals may enlarge following occlusion of the ICA and have been implicated in the development of dural arteriovenous fistulas (dAVF).

A non-exhaustive list of such sites includes:

orbit
- ophthalmic artery (ICA) – middle meningeal artery (ECA) ¹
- the ophthalmic artery most commonly arises from the supraclinoid (C6) segment of the ICA but may arise from the middle meningeal artery or middle cerebral artery
- ophthalmic artery may have collaterals with the middle meningeal artery or with the deep temporal artery or infraorbital artery (from the maxillary artery)
ethmoidal sinuses
- anterior and posterior ethmoidal arteries (ICA) – sphenopalatine artery (ECA) ¹
- both anterior and posterior ethmoidal arteries are branches of ophthalmic artery
scalp
- superior orbital artery (ICA) – superficial temporal artery (ECA) ¹
- the superior orbital artery is a branch of the ophthalmic artery
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
cavernous sinus
- inferolateral trunk (ICA) – branches of maxillary artery (ECA) ¹
- the inferolateral trunk is a variably identified branch of the cavernous (C4) segment of the ICA. Branches of the inferolateral trunk may anastomose with the middle meningeal artery/deep temporal artery/artery of the foramen rotundum ¹.

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 ¹.