Internal maxillary system

It is important to understand that all the EGA branches are in a hemodynamic balance. The internal maxillary system consists of two groups of branches, whether their course is intracranial or extracranial. 

The original ventral pharyngeal artery turns into the facio-lingual system, while the hyoid artery and the stapedial artery will evolve to become the internal maxillary artery and the middle meningeal artery (Figs. 18.3, 18.4)... 

The arteries that supply the peripheral cranio-encephalic system (cranial nerves), which evolve from internal carotid to external carotid arteries, like the maxillary system that arises originally from the stapedial artery. 

There are multiple anastomoses between the intraorbital branches with the external carotid system only supplying the periorbital region. This includes the internal maxillary, superficial temporal arteries and the facial system. 

The sphenopalatine artery, the terminal branch of the internal maxillary artery enters the nasal cavity where it is divided into a septal, medial branch and a lateral branch that supplies the conchae. These two arteries have a distinctive appearance on the angiographic views. These branches usually anastomose with the anterior and posterior ethmoidal arteries, which arise from the ophthalmic artery system, at the anterior and posterior ethmoidal cells, and eventually connects the external and internal carotid... 

Autoregulation mechanisms have been described to be more effective in the internal maxillary artery and the pharyngo-occipital system, whereas the facial artery has not shown to respond as effectively. Vasoconstriction as a response for hypertension or mechanical trauma is observed in large or medium sized arteries whereas small distal arteries seem to react with true regulatory mechanisms. 

The initial study in idiopathic EPX should involve the internal carotid artery ipsilateral to the bleed, using both lateral and AP views in order to detect any lesion of the petrous or cavernous segment of this vessel. This also allows the evaluation of nasal fossa vascularity that originates from the ethmoidal arteries. Angiography of internal maxillary artery is then performed in lateral views to depict any culprit anastomoses with the internal carotid system, as the external carotid origin of the ophthalmic artery. These... 

Fig.23.10a,b. Juvenile nasopharyngeal angiofibroma in an 11-year-old boy. Preoperative embolization with particles of the arterial branches of the internal maxillary artery, a Selective external carotid angiogram shows a vascular tumor fed by multiple branches of the internal maxillary artery.b After multiple selective catheterization with a coaxial system (Tracker 38 and Tracker 18), embolization was performed with particles. Postembolization angiogram shows significant devascularization... 

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