Microsurgical Anatomic Study Of Saddle Area, The Lateral Sellar Compartment, Petroclival Region And Its Related Structures

Objective To study the surgical microanatomy of saddle area,thelateral sellar compartment,petroclival region and its related structures. MethodsThe microsurgical dissections were performed on 20 cadaveric heads with the aid ofan operating microscope to observe and measure the dura,nerves and vessels in thesphenopetroclival region,and to learn the relationships among the dura nerves andvessels with histochemical technique. To measure the depth, width and thickness ofthe superior and inferior Meckel's cave, as well as the length, width and thickness oftrigeminal ganglion. And measure the cisternal segment of oculomotor nerve,trochlear nerve, trigeminal nerve, abducent nerve and facial nerve. Results Inmiddle cranial fossa,cranial nervesⅢ,ⅣandⅥ, which were enwrapped by arachnoidand dura,entered between the dura of middle cranial fossa．The Meckel's cave,thetrigeminal ganglion and its three branchs,just like a glove,were embedded betweenthe dura of middle cranial fossa,and ICA and some venous structures traveled amongthem．Cavernous sinus and those structures were located in a cave made up of twofloors of the middle cranial fossa dura,namely dura mater space．Cranial nerves arevery close to anterior clinoid bone in the central and roots of anterior clonid,particularly the oculomotor nerve and trochlear nerve are almost close to theperiosteum. The average depth of inferior Meckel's cave is 13.87±1.20mm, theinferior is 15.32±1.28mm, the average width is 12.11±0.74mm, the averagethickness is 5.45±0.51mm. The average length of the trigeminal ganglion is 11.43±1.02mm, the average width is 10.21±1.01mm, the average thickness is 3.46± 0.64mm. The cisternal segment lengths of the oculomotor nerve, trochlear nerve,trigeminal nerve, abducent nerve and facial nerve were 18.8±2.8, 35.9±3.1, 12.8±1.7,17.5±1.9 and 13.2±2.2 mm respectively. The mean distance from the point where thetrochlear nerve enters into the edge of tentorium cerebelli to the oculomotor nervewas 5.4 mm (ranged 4.2 to 6.8 mm). Conclusion We suggest new constructiveconceptions about these regions which are the surgical anatomy base of skull baseapproaches.