Angiographic anatomy of the first and second segments of the maxillary artery.

The increasing use of interventional angiography makes it important to know the anatomy of the maxillary artery. The course and ramification pattern of the first and second segments of this artery were studied angiographically in 100 cases. The branches of the maxillary artery were identified on lateral stereoscopic images. The maxillary artery has three segments divided by the external pterygoid muscle, and the second of these segments divides into superficial and deep types. Of the 100 Japanese angiograms, 93% were of the superficial type and 7% of the deep type. The 93% was a much higher incidence than in Western populations. In the superficial types, the middle deep temporal artery and inferior alveolar artery arose separately from the maxillary artery, while in the deep types, they had a common trunk. This made it easy to differentiate the two types. The maxillary artery was classified into four subgroups (Ia, Ib, IIa and IIb) by the ramification patterns of the middle meningeal and accessory meningeal arteries from the first segment.