Functional Arterial Anatomy of the Cranial Base

Area of Science:

• Neuroanatomy
• Vascular Surgery
• Embryology

Background:

• The brain receives blood supply from internal carotid arteries (ICAs) and vertebral arteries.
• The external carotid artery (ECA) primarily supplies extracranial structures.
• Extracranial-intracranial anastomoses are developmental remnants, not newly formed vessels.

Purpose of the Study:

• To review the embryological development of the ECA.
• To explain the functional anatomy of extracranial-intracranial anastomoses.
• To highlight the importance of understanding these anastomoses for neurointerventionalists.

Main Methods:

• Review of embryological processes related to cranial vasculature.
• Discussion of the segmental concept of the ICA.
• Analysis of the anatomical pathways of ECA-ICA and ECA-vertebral anastomoses.

Main Results:

• Extracranial-intracranial anastomoses arise from developmental processes involving pharyngeal arches.
• Key contributing arteries include branches of the maxillary artery, ascending pharyngeal artery, ophthalmic artery, and ICA branches.
• Understanding these pathways is vital for neurointerventional procedures in the ECA territory.

Conclusions:

• Embryological knowledge is essential for comprehending the routes and patterns of extracranial-intracranial anastomoses.
• Awareness of these anastomoses is critical for neurointerventionalists to avoid embolic complications and cranial nerve palsy.
• This review provides an embryological perspective on these vascular connections in the orbit, cavernous sinus, petrosal bone, and posterior fossa.