From the Idea to Its Realization: The Evolution of Minimally Invasive Techniques in Neurosurgery

Figure 2

Krönlein’s construction of the central region and the Sylvian fissure based on external anatomical landmarks. The horizontal inferior orbitomeatal line is the base line. The parallel supraorbital line marks the inferior border of the central region and the Sylvian fissure. By means of additional three perpendicular vertical lines, first at the anterior zygomatic bone, second at the level through the temporomandibular joint, and the last immediately behind the mastoid, the position of the central region can be drawn into X-ray images or on the head of the patient.