The PSL (Gruber‘s ligament) is an important structure in the petroclival region. In this study, microanatomical characteristics were described in detail, along with new descriptions of its shape.

Object. The C-2 pedicle plays an important role regarding screw purchase for spinal fixation. The aim of this study was to measure the C-2 pedicle—related linear and angular parameters. Methods. Seven parameters in 160 C-2 pedicles (80 dry vertebrae) were measured using a Vernier caliper (accurate to 0.1 mm) and goniometer. The Student t-test was used to determine statistical significance. The authors found that the C-2 isthmus (pars interarticularis) and the C-2 pedicle are distinct structures. The C-2 isthmus covers the pedicle. The isthmus is present between the superior and inferior articular processes, and the pedicle is the structure beneath the C-2 isthmus. It connects the lateral mass—inferior articular process to the body of the axis. The heights of the right and the left C-2 pediculoisthmic components (PICs) were 10.3 ± 1.6 and 9.9 ± 1.5 mm, respectively. The posterior part of the superior aspect of the PIC was wider than the anterior portion. The widths of the posterosuperior aspect of the PIC were 11.1 ± 2 and 11 ± 1.7 mm on the right and left sides, whereas the widths of the anterosuperior aspect of the PIC were 7.9 ± 1.7 and 8.5 ± 1.6 mm, respectively. The inferior widths of this component were 6.0 ± 1.5 and 5.5 ± 1.3 mm on the right and left side, respectively. The lengths of the component were 28.8 ± 2.9 mm on the right and 28.8 ± 3.4 mm on the left side. The PIC exhibits a lateral-to-medial and an inferior-to-superior angle. Its axial angles were 28.4 ± 2.5 and 28.6 ± 2.2° on the right and left sides, respectively; its sagittal angles were 18.8 ± 2.1 and 18.8 ± 1.7°, respectively. Conclusions. The C-2 pedicle can be seen in the inferior aspect of the vertebra, and it connects posterior vertebral elements (that is, the lateral mass and inferior articular process) to the axial body. The isthmus drapes the pedicle. The authors suggest that this be termed “the pediculoisthmic component.”

AIM:The microanatomy of the abducens nerve (AN) is important for clinical reasons and surgical approaches as it is located in the petroclival region. The incidence of branching and duplication of the abducens nerve are unknown and mechanisms relating to paralysis of the nerve in indirect conditions are yet to be clarified. MATeRIAL and MeTHodS:Microanatomical details (anatomical observations and morphometric measurements) of the AN were obtained from 20 cadaveric skull bases (40 specimens). ReSULTS: 55% of the intracranial abducens nerves had branching, with type 2 and 3 branching occurring in 10%. The nerve coursed below the petrosphenoidal ligament in all but one, and was located at the lateral third below the ligament in 82.5% of the specimens. The mean AN diameter was 1.3±0.2 mm, and the mean diameter of the dural entrance pore was 1.8±0.3 mm, the right being significantly larger than the left. The mean distance of the AN from the posterior clinoid process was 8.4±2.5 mm and from the petrous apex 3.6±2.1 mm. CoNCLUSIoN: Branching of the AN was present in a significant number of specimens; the branching pattern at the cavernous segment may be called "pseudobranching". The AN is at risk for paresis in indirect conditions because of its angles and fixations on its course.

The authors report a case of craniopharyngioma presenting in the right cerebellopontine angle. The tumor was removed totally. The purpose of this report is to record this very unusual localization of a craniopharyngioma.

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