The vertebral arteries fuse at the junction between the medulla and the pons to form the single midline basila artery which then proceeds rostrally along the surface of the anterior pons. PICA has a complicated looping course as it swings out around the inferior olives, and runs along the dorsal lateral surface of the medulla before turning laterally and supplying the inferior surface of the cerebellum. From its lateral side each vertebral gives off a variable branch, the posterior inferior cerebellar artery (PICA). The midline anterior spinal artery, formed from the fusion of medial branches from each vertebral, supplies part of the central medulla (as well as much of the upper cervical cord). The blood supply of the medulla is derived from the two vertebral arteries. Pontine lacunar infarcts may also damage the corticospinal tracts. Large pontine hemorrhages classically involve the corticospinal tracts and reticular formation bilaterally. dorsolateral parts of the brainstem are supplied by direct circumferential branchesof the vertebral or basilar arteries, or by branches of one of the major 'cerebellar' vessels as they curve around the brainstem on their way to the part of the cerebellum they supply.Ĭlinical Note: Like the lenticulostriate branches of MCA, the paramedian vessels supplying the medial parts of the brainstem are at risk for hypertensive damage, particularly in the pons.medial parts of the brainstem as far dorsal as the ventricle are supplied by long, slender penetrating branches called the paramedian branches.
Patients whom you will encounter may present with fragments or combinations of syndromes.īrainstem arteries in the medulla, pons and midbrain have similar patterns of distribution: This means that clinical syndromes produced by occlusion of a particular vessel are also variable. Perhaps the most important thing to recognize about the brainstem's blood supply is just how variable the vessels can be in size and position, but still provide adequate perfusion. The vertebral and basilar arteries supply the brainstem and cerebellum. The artery of Adamkiewicz is one of the most important radicular arteries, and in some individuals it may provide the entire arterial supply for the lower two-thirds of the spinal cord. There is a great deal of variability in this pattern. For lower parts of the cord, the spinal arteries are reinforced by radicular arteries that are branches of the thoracic and abdominal aorta. The posterior spinal arteries and the two anterior spinal arteries, which fuse to form a single midline vessel, supply the upper cervical cord. Diagrams The vertebral arteries help to supply the spinal cord
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