[Variants of the structure and topography of the superior limit of the epidural space of the human spinal cord].

Variants of the structure of the superior limit of the epidural space at the sites of the spinal cord dura mater transition into cerebral dura matter were studied. Four levels of the superior limit position of the anterior (intracranial location, inferior limit of occipital bone, bodies of C(I) and C(II)) and five levels of the posterior sections (occipital bone, occipital bone-arch of C(I), C(II), C(I),-C(II), C(II)) of the epidural space were determined by the method of stereoepidurography (88 objects) and by corrosion (49 objects). Variants of the superior margin form of the anterior (in the frontal surface: falciform, oval and dentate forms and in the sagittal: pointed, flexured calcars, pointed slit and olive-shaped) and posterior portions (collar-shaped, oval, bidentate fork with equidimensional or unequidimensional teeth) of the epidural space caused by the asymmetry of fixation of the spinal cord dura matter to the walls of the spinal canal were described. Weak places of the superior wall in the epidural spaces (area of the spinal cord dura mater transition into the cerebral dura mater, paravasal capsule of the spinal artery, area of the first intervertebral foramen) were detected.