Anatomic and topographic variability of medial intracranial structures
Objective: to analyze correlation between the shape and size of the tentorial incisure (TI) and craniometric parameters (including shape and size of the skull and angular parameters of the skull base). Materials and methods. We analyzed 100 samples of TIs and measured latitudinal and longitudinal parameters of the TI, cranial indices, and angular parameters of the skull base relief. Morphometric analysis was performed with the calculation of coefficients and indicators. Data analysis was conducted using the Statistica software. Microsurgical anatomy of the anterior and posterior parts of the TI was evaluated using operating microscope MBS-10 and digital video camera "Sony" HDR-CX 560 E. Results. Using the results of craniometric and morphometric analysis, we identified 4 types of TIs: A, B, C, and D. We found that in mesocephalic skulls, mean TI values were determined by the shape of the TI apex. Type A was characterized by a sharp and high apex, whereas type B was characterized by a low and flat apex. Dolichocranic skulls had longer TI. In subbrachycephalic skulls, the free TI edges had steeper location in the area of the TI apex with minimal protrusion of the inferior cerebellar vermis in the posterior parts of the TI. In brachycephalic skulls, the TI was relatively small and narrow. We have developed an algorithm for evaluating MRI findings to measure TI and predict its shape. Conclusion. We found a correlation between the shape of TI and skull shape. The proposed classification and morphometric analysis of the TI shapes can be used in patients with cancer or vascular disorders in the preoperative period in order to justify the adequacy of the selected access. The type of brain herniation depends on the size of the anterior, middle, and posterior TI portions.