Albert L. Rhoton

The foramen magnum.

The foramen magnum is located in the occipital bone, which has three parts: a squamosal part located behind the foramen magnum; a basal (clival) portion located anterior to the foramen magnum; and a condylar part that connects the squamosal and clival parts (Fig. 6.1). The suboccipital approaches are directed through the squamosal part and the anterior approaches through the clival part. The condylar part, which includes the occipital condyle, posterior margin of the jugular foramen, and hypoglossal canal, is exposed in the far-lateral approach and its transcondylar, retrocondylar, and supracondylar modifications described in the chapter on the far lateral approach. Structures involved in foramen magnum lesions include the lower cranial and upper spinal nerves, the caudal brainstem and rostral spinal cord, the vertebral artery and its branches, the veins and dural sinuses at the craniovertebral junction, and the ligaments and muscles uniting the atlas, axis, and occipital bone (5, 26). The foramen magnum is most commonly approached from posteriorly through the suboccipital and upper cervical region or from anteriorly through the nasal and oral cavities, the pharynx, or maxilla.

Case 15-1

• Dividends — In each calendar year, the holders of the then outstanding Series B Preferred Stock are entitled to receive, when, as and if declared by the Company’s board of directors, cumulative dividends at the annual dividend rate of 8 percent of the Original Issue Price, as appropriately adjusted for any stock dividends, combinations, reclassifications, recapitalizations, or splits with respect to such shares.

Case 16-4

RSUs are a form of compensation offered by an employer in the form of company stock. These shares of company stock are “restricted” in that they vest only after certain conditions (restrictions) are met. The shares are earned or “vested” based on a vesting schedule consistent with the satisfaction of these conditions. Vesting schedules are specific to each award and can be based on various conditions such as service (remaining with the employer for a certain period of time), performance milestones (such as meeting sales goals), or a combination.