Posterior spinal artery

Medullary infarcts can be medial, lateral or combined (Fig. 14.6). The medial territory is supplied by penetrating vessels from the anterior spinal artery and the distal vertebral artery. The lateral territory main arterial supply comes from penetrating arteries from the distal vertebral artery and the posterior inferior cerebellar artery. The small posterior territory is supplied by the posterior spinal artery and the posterior inferior cerebellar artery. Medial... 

Mascalchi M, Cosottini M, Ferrito G, Salvi F,Nencini P, Quilici N (1998) Posterior spinal artery infarct. AJNR Am J Neuroradiol 19 361-363... 

Spiller W (1909) Thrombosis of the cervical anterior median spinal artery. I Nerv Ment Dis 36 601 Stein SC, Ommaya AK, Doppman JL, Di Chiro G (1972) Arteriovenous malformation of the cauda equina with arterial supply from branches of the internal iliac arteries. Case report. J Neurosurg 36 649-651 Stepper F, Lovblad KO (2001) Anterior spinal artery stroke demonstrated by echo-planar DWI. Eur Radiol 11 2607-2610 Suh T.H., Alexander L (1939) Vascular system of the human spinal cord. Arch Neurol Psychiat 41 659-677 Suzuki T, Kawaguchi S, Takebayashi T, Yokogushi K, Takada J, Yamashita T (2003) Vertebral body ischemia in the posterior spinal artery syndrome case report and review of the literature. Spine 28 E260-264... 

The arterial blood supply of the spinal cord is provided by the unpaired anterior spinal artery (ASA) and the paired posterior spinal arteries. These vessels constitute a longitudinally orientated arterial system that is interconnecting with numerous arteries entering transversely and resembling the segmental embryology of the spine (Gillilan 1958 Lasjaunias and Berenstein 1990). 

The ASA is transversely reinforced by branches of deep cervical arteries at the neck and by posterior intercostal (PIA) and upper lumbar arteries at the trunk. Both of the latter derive segmentally from the descending thoracic and abdominal aorta and range between 0.5 and 5mm in diameter (Boll et al. 2006). The PIA and lumbar arteries send rami dorsales, from which again the radicular arteries (synonymous with radicomed-ullary artery or spinal branch) as feeders of the spinal cord originate. The radicular arteries divide soon into anterior and posterior branches that support either the anterior or the posterior spinal arteries. 

The posterior spinal arteries arise from the vertebral or posterior inferior cerebellar arteries and pass as two at each side along the dorsal aspect of the spinal cord. They are sustained to the lower spinal levels by being predominantly fed by the posterior branches of the radicular arteries. The posterior spinal arteries supply the dorsal third of the spinal cord and have a caliber of less than 0.5 mm. 

For classification, the anatomical relationship to associated extradural, intradural, or intramedullary vasculature has to be depicted. While extradural lesions are fed by arterial branches generally arising from extradural portions of the radicular arteries, intradural and intramedullary lesions show a supply from intradural radicular pedicles or from the ASA or posterior spinal arteries (Kim and Spetzler 2006). 

In blockade of the anterior spinal artery, ischemia of the medial medulla may occur with contralateral hemiparesis, ipsilateral tongue weakness and contralateral loss of posterior column sensation (Ho and Meyer 1981). 

Vertebral arteries vary in size and symmetry, where mostly the left vertebral artery is the dominant one. The coincidence of vertebral fenestrations and aneurysms is well known. The anterior spinal artery receives tiny vessels from the vertebral arteries which are physiologically not depicted by MRA due to their size. The posterior inferior cerebellar artery (PICA) as the largest, most important and most variable cerebellar artery however, under normal conditions it is constantly depictable with TOF and CE-MRA. 

Fig. 17.2. a Superficial arteries of the spinal cord. X-ray film of an injected specimen in a.p. view. The anterior spinal artery system is visible on the ventral surface of the cord, b Intrinsic spinal cord arteries. X-ray microangiogram of a transverse section (lumbar enlargement). The sulcal or central artery within the anterior fissure (arrow) is dominant. Note the posterior and posterolateral spinal arteries at both sides of the posterior root entry zone (arrowheads). AST, anterior spinal artery... 

AVMs of the perimedullary fistula type are direct AV shunts that are located on the ventral or dorsal surface of the spinal cord or the conus medullaris, usually in the thoracolumbar area, occasionally thoracic, and rarely cervical. Their location thus is intradural, intra- or extramedullary. They are always supplied by spinal cord vessels, either by the anterior spinal artery (ventrally) or by a posterolateral artery (dorsally), depending on their location. They drain into spinal cord veins (Fig. 17.12). Drainage may even ascend up to the foramen magnum or into the posterior fossa. 

The posterior cerebral artery supplies the occipital lobe and portions of the medial and inferior temporal lobe. The arterial supply of the spinal cord is derived from the vertebral arteries and the radicular arteries. The brain is supplied by the internal carotid arteries (the anterior circulation) and the vertebral arteries, which join at the pon tomedullary junction to form the basilar artery (collectively termed the posterior circulation). The brainstem is supplied by the posterior system. The medulla receives blood from branches of the vertebral arteries as well as from the spinal arteries and the posterior inferior cerebellar artery (PICA). The pons is supplied by paramedian and short circumferential branches of the basilar artery. Two major long circumferential branches are the anterior inferior cerebellar artery (AICA) and the superior cerebellar artery. The midbrain receives its arterial supply primarily from the posterior cerebral artery as well as from the basilar artery. The venous drainage of the spinal cord drains directly to the systemic circulation. By contrast, veins draining the cerebral hemispheres and brain stem drain into the dural sinuses. Cerebrospinal fluid also drains into the dural sinuses through unidirectional valves termed arachnoid villi. 

Fig. 24.1. Anatomy of feeding arteries of the spinal cord. 1 vertebral artery, 2 left subclavian artery, 3 posterior intercostal artery, 4 anterior spinal artery, 5 Adamkiewicz artery,...

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