The superior cerebellar artery is derived from the basilar artery near the pons-midbrain junction. In some specimens the anterior inferior cerebellar artery may come off the basilar artery near its origin. Locate the basilar artery on the whole brain specimen. The basilar artery is a large midline arterial trunk formed by the fusion of the vertebral arteries on the anterior surface of the brain stem. Follow this artery as it courses up to the cerebellum to supply the inferior surface of the cerebellum and the choroid plexus of the fourth ventricle. In its course along the medulla it gives off small branches to supply posterolateral regions of the medulla. On the whole brain follow the posterior inferior cerebellar artery (PICA) as it travels along the lateral and posterior surface of the medulla. The posterior inferior cerebellar artery usually arises from the vertebral artery, but its position of origin is quite variable on the parent vessel. These arteries merge to form a single artery which descends in the anterior median fissure of the spinal cord. See if you can find branches of the anterior spinal arteries which supply the anterior and midline regions of the medulla. Note that the posterior spinal arteries descend to, and supply the spinal cord. Branches of this artery supply posterior areas of the medulla that are also supplied by branches of the vertebral artery (caudally) and the posterior inferior cerebellar artery (rostrally). Follow the posterior spinal artery as it passes posteriorly along the medulla. Posterior Spinal ArteriesĪs noted above, the posterior spinal arteries arise from the vertebral arteries and descend along the posterolateral aspect of the medulla and spinal cord. The paired vertebral arteries pass rostrally and unite near the pontomedullary junction to form the basilar artery. The paired vertebral arteries pass over the anterior surface of the medulla and give rise to the posterior spinal arteries, the anterior spinal arteries and the posterior inferior cerebellar arteries. As you become more familiar with the functional anatomy of the brain stem, return to this figure and consider the consequences of occlusion of the various vessels. Lab 4 (ƒ3) - The Ventricles and Blood Supply Vertebral-Basilar SystemĮxcept for the most rostral portion of the crus cerebri, the entire blood supply of the brain stem (i.e., midbrain, pons and medulla) and cerebellum is derived from the vertebral-basal system.
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