Spinal arterial supply

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. 

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... 

Segmental arteries supply the spine with blood, including the vertebral bodies, paraspinal muscles, dura, nerve roots, and spinal cord. All these tissues, with the exception of the spinal cord, receive their blood supply from segmental arteries (one on each side) or their equivalents. In particular, the segmental supply of the thoracolumbar region is derived from intercostal and lumbar arteries arising from... 

Those spinal radicular arteries that are radiculo-medullary arteries, supplying nerve root, pial plexus and medulla, branch in a very typical way to form the anterior spinal artery. The ascending branch continues the direction of the radicular artery in the midline of the anterior surface. The descending branch, being the larger one at thoracolumbar levels, forms a hairpin curve as soon as it reaches the midline at the entrance of the anterior fissure (Fig. 17.3). The artery runs above the vein. The maximum diameter of a spinal radiculomedullary artery or the anterior... 

Thus, acute, subacute, or chronic impairment of spinal blood supply can result from a deficient arterial supply and from venous circulatory problems (Mull and Thron 2004). Spinal vascular malformations like spinal dural arteriovenous (AV) fistulas and AV malformations (AVM) of the perimedullary fistula type are the typical disorders associated with venous congestion of the spinal cord. On the other hand, AVM of the glomerular type are seldom combined with a venous outflow disorder. 

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. 

Selective spinal DSA has a better spatial resolution and plays a main role in the exclusion of spinal vascular malformations. In selected cases affection of the radicular artery and occlusion of the anterior spinal artery system can be demonstrated as well as collateral supply even in the later course of the ischemia (Mull et al. 2002). Thus, spinal DSA helps to identify pathologic vascular conditions in spinal cord ischemia. The main indication remains to exclude a spinal vascular malformation. Angiographic information about the acute phase of spinal cord ischemia is not yet available. 

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 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. 

Communications between bronchial arteries and systemic vessels are ubiquitous, and can sometimes complicate an embolization procedure. The most commonly seen communication is that of a right intercostobronchial trunk with an anterior medullary artery that contributes to the vascular supply of the spinal cord through the anterior spinal artery. The anterior medullary arteries have a characteristic hairpin configuration, and follow a course... 

Because transvenous embolization is not feasible for spinal lesions, transarterial embolization with glue is the treatment of choice for a spinal DAVM with an arterial feeder that allows safe and distal catheterization and does not supply the anterior spinal artery. Glue should be pushed until it reaches the draining vein (Fig. 4.18) (Cognard et al. 1996 Song et al. 2001). Clinical outcome seems to dependent on the severity of the symptoms at the time of treatment (Nagata et al. 2006). 

The treatment of spinal DAVM by surgery is easy, safe, and effective and requires interruption of the draining vein at its dural entrance only (Anson and Spetzler 1992). Therefore, embolization of spinal DAVM should be offered only if the feeding pedicle provides a safe approach to a position close to the fistula site and it does not give rise to radiculomedullary branches supplying the anterior spinal artery. If there is a risk of reflux into the anterior spinal artery, surgery is significantly safer and should be performed. 

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). 

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). 

Spinal DSA is still required to demonstrate the fistula and the supplying segmental artery. Recent developments in MR angiography will help to define non-invasively the level of the fistula (Farb et al. 

AVMs of the glomerular type are more frequent and characterized by a nidus similar to those of most cerebral AVMs. They may be located superficially on the surface of the spinal cord or deep within the cord parenchyma or extend to both compartments. Due to the numerous anastomoses between the spinal cord arteries, the nidus is always supplied by several arteries or branches derived from the anterior... 

To identify the location of cord-supplying segmental arteries before aortic surgery can help to reduce the risk of spinal cord ischemia. Monitoring of somatosensory-evoked responses contrib-... 

Larsen DW, Halbach VV, Teitelbaum GP, McDougaU CG, Higashida RT, Dowd CF, Hieshima GB (1995) Spinal dural arteriovenous fistulas supplied by branches of the internal iliac arteries. Surg Neurol 43 35-40 discussion 40-1 Lasjaun ias P, Berenstein A, ter Brugge KG (2001) Surgical Neu-... 

Both patients had lesions in the medial medulla supplied by branches of the anterior spinal and vertebral arteries, and although such cases are rare it seems wise, in the light of these reports, to avoid the routine use of adrenaline as an adjunct to local anesthesia for adenotonsillectomy. 

The nerve supply to the liver comes from the vagus and phrenic nerves and the sympathetic ganglia originating from cell bodies in the spinal cord that are located between the seventh and the tenth thoracic vertebrae. These merge to accompany the hepatic artery and bile ducts throughout the liver. 

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