The Relationship of the Vertebral Artery with Anatomical Landmarks in the Posterior Craniovertebral Junction of Fresh Human Cadavers in the Turkish Population.

arch of the atlas to the spinous process of the axis with a heavy silk thread (20). Since then, other techniques have been developed. These include wire fixation with a midline graft (Gallie-type), wire fixation with two laminar grafts (Brookstype), transarticular screw fixation (Magerl technique), and bilateral laminar clamps (Halifax technique) (4, 19, 20). The most recent technique involves screw fixation of the lateral mass of C1 with pedicle screws to C2—the so-called Goel technique as modified by Harms (29). The proximity of the VA, spinal cord, and C-2 ganglion and nerve root to the upper cervical spine has confirmed the difficulty of the surgery in this region. █ INTRODUCTION The craniovertebral junction and upper cervical spine surgery requires a three-dimensional understanding of the anatomy. Instability in the upper cervical spine can occur when any part of the components are damaged by congenital defects, neoplasm, inflammation, or trauma including fractures of occipital condyle, atlas, axis and atlantooccipital and atlantoaxial dislocations. In 1910, the first description of surgical treatment with posterior approach for instability of upper cervical spine appeared in the literature. Mixter et al. reported securing the posterior AIm: Surgical anatomy concerning the posterior craniovertebral region in fresh human cadavers was studied to provide most accurate information for the surgical approach. mATERIAl and mEThODS: In thirty-two fresh human cadavers, the distance from the posterior tubercle to the sulcus of vertebral artery (VA), the thickness and length of the third segment of VA (V3), the distance of C1/C2 facet to V3, the length, height and shape of the C2 ganglion to the neighboring structures, the distance from medial border of C1 lateral mass to dura mater, the distance of the transverse process of atlas to mastoid tip, the thickness of C1 posterior arcus were measured. RESUlTS: There were variations of sulcus of VA in 14 of 32 cadavers (43.7%), the right VA was larger in 23 cadavers (71.8%). The ganglion was found over the C1 lateral mass screw entry point in 45 of 64 ganglions (70.31%) and below the screw entry point in 19 of 64 ganglions (29.69%). The distance of the medial border of the C1 lateral mass to dural tube was 3.81±0.55 mm at the right side and 3.91±0.59 mm at the left. The thickness of C1 posterior arch was 3.73±0.75 mm at the right side and 3.75±0.77 mm at the left. The mean distance from the transverse process of C1 to the mastoid tip was 15.82±4.49 mm at the right side and 15.46±4.38