Direct Origin of the of the Cervical Enlargement from the Left

Donald L. Miller

Summary: An anatomic variation is described in which the trunk and internal mammary artery were catheterized and principal radiculomedullary artery to the cervical , imaged in routine fashion. On the left, the internal mam­ the artery of the cervical enlargement, arises directly from the mary artery was examined and was unremarkable. left subclavian artery. This anomaly is important clinically The catheter was then introduced into a vessel believed because it may be necessary to catheterize this vessel selec­ to be the left inferior artery. On fluoroscopy, injec­ tively during spinal arteriography, and also because uninten­ tion of contrast material into this vessel showed that it had tional injection of this vessel can be associated with complica­ a superior and medial course, similar to the ascending tions. portion of the characteristic loop of the . Index terms: , abnormalities and anomalies; Arteries, Digital subtraction arteriography (DSA) of this vessel anatomy; Arteries, spinal was performed with a gentle hand injection of contrast material. DSA images were monitored during the injection, The principal arterial supply to the anterior and it was immediately obvious that the anterior spinal spinal artery in the cervical spinal cord is from artery was opacified (Fig. 1). The catheter was pulled down anterior spinal branches of the vertebral arteries and out of the vessel approximately 1.5 seconds after the and from radiculomedullary branches of the ver­ beginning of the injection. The patient had no neurologic tebral artery and (1-5). There symptoms. A left subclavian arteriogram was performed, is considerable variation in the precise origin of followed by catheterization and arteriography of the left (Figs. 2 and 3). The costocervical trunk (4-6). these branches The thyrocervical trunk has was clearly visible on both of these arteriograms, and it been reported to supply branches to the spinal was clear that the catheter had not been in either the cord as well, via the ascending cervical artery (5), thyrocervical trunk or the costocervical trunk or in a branch but an extensive series of thyrocervical trunk of either trunk. There were no neurologic sequelae as a arteriograms suggest that this is rarely the case result of the procedure. (7). The largest radiculomedullary branch to the cord in the region of C5-C6 has been termed the Discussion artery of the cervical enlargement (ACE) by La­ zorthes (8). This report describes an anatomic Spinal arteriography requires adequate dem­ variation in which this vessel arises directly from onstration of the in the area the left subclavian artery (LSA). of interest. When the cervical portion of the spinal cord is studied, it is common to catheterize selec­ tively both vertebral arteries and both costocerv­ Case Report ical trunks. Normally, this is sufficient. However, A 49-year-old woman underwent parathyroid arteriog­ there is enormous variation in the anatomy of the raphy to locate a parathyroid adenoma following an unsuc­ branches of the subclavian artery (9). When an cessful surgical exploration. Arteriography of the right and anatomic variant is present, such as the one left thyrocervical trunks and internal mammary arteries is described here, additional vessels may need to be a standard part of this procedure. The right thyrocervical examined. A subclavian artery arteriogram may

Received March 5, 1992; accepted April 22. Diagnostic Radiology Department, Warren Grant Magnuson Clinica l Center, National Institutes of Health, and the Department of Radiology, Georgetown University Medica l Center, Washington, DC Address reprint requests to Donald L. Miller, MD, Diagnostic Radiology Department, Building 10, Room 1C 660, National Institutes of Health, Bethesda, MD 20892.

AJNR 14:242-244, Jan/ Feb 1993 0 195-6108/ 93/ 1401 -0242 © American Society of Neuroradiology 242 AJNR: 14, January / February 1993 ORI GIN OF THE ACE FROM THE LSA 243

Fig. I. Selective arteriogram of anomalous arte ry of the cervical enlargement. A, Earl y in the injection, the .... artery is visualized throughout its course (short arrows), and there is filling of the anterior spinal artery both superior and inferior to the .... point of anastomosis with the ar­ tery of the cervical enlargement (long arrows). Note that the artery of the cervical enlargement has no branches. B, One second later in the in­ jection, there is reflux into the left subclavian artery, outlining the su­ perior aspect of the arteri al lumen (long arro w). There is also opaci­ fication of the costocervica l trunk (short arrows). The ante rior spinal artery is well seen.

A B

Fig. 2. Selective arteriogram of the left thyrocervical trunk. A, The loop of the inferior thy­ roid artery is well seen (long ar­ row), as is the vascular bl ush of the left lobe of the thyroid gland (short arrows). There is no filling of the anterior spinal artery. B, A later image from the sa m e study shows reflux into the left subclavian artery, with opacifica ­ tion of the left costocervical trunk (short arrows) and the inferior th y­ roid (long arrows). There is no filling of the anterior spinal ar­ tery, and the anomalous artery of cervical enlargement is not identi­ fied.

A B help to suggest other possible sites of origin of artery of cervical enlargement in this patient has radiculomedullary branches. no other branches besides those to the anterior Knowledge of this variation is also important spinal artery, and a forceful, wedged, or pro­ in order to avoid a complication. The anomalous longed injection could produce severe damage to 244 MILLER AJNR: 14, January / February 1993

the spinal cord. This case serves as a useful reminder that selective arteriography of the prox­ imal branches of the subclavian artery must al­ ways be performed with extreme caution.

Acknowledgments

I thank Giovanni Di Chiro, MD, for reviewing the case and John L. Doppman, MD, for reviewing the manuscript.

References

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