Fig. 43-8. Craniocerebral topography. The middle meningeal artery proceeds from the middle of the zygomatic arch upward (dotted line) about 4 to 5 cm to the pterion (P). The external acoustic meatus is shown in black. B, bregma; I, inion; L, lambda; XY, orbitomeatal plane. (After von Lanz and Wachsmuth.) Click for high resolution image.