Résumé : Objective: To examine whether risk factor profile, baseline features, and outcome of cervical artery dissection (CEAD) differ according to the dissection site. Methods: We analyzed 982 consecutive patients with CEAD included in the Cervical Artery Dissection and Ischemic Stroke Patients observational study (n = 619 with internal carotid artery dissection [ICAD], n = 327 with vertebral artery dissection [VAD], n = 36 with ICAD and VAD). Results: Patients with ICAD were older (p < 0.0001), more often men (p = 0.006), more frequently had a recent infection (odds ratio [OR] = 1.59 [95% confidence interval (CI) 1.09-2.31]), and tended to report less often a minor neck trauma in the previous month (OR=0.75 [0.56-1.007]) compared to patients with VAD. Clinically, patients with ICAD more often presented with headache at admission (OR = 1.36 [1.01-1.84]) but less frequently complained of cervical pain (OR = 0.36 [0.27-0.48]) or had cerebral ischemia (OR = 0.32 [0.21-0.49]) than patients with VAD. Among patients with CEAD who sustained an ischemic stroke, the NIH Stroke Scale (NIHSS) score at admission was higher in patients with ICAD than patients withVAD(OR=1.17 [1.12-1.22]). Aneurysmal dilatation was more common (OR = 1.80 [1.13-2.87]) and bilateral dissection less frequent (OR = 0.63 [0.42-0.95]) in patients with ICAD. Multiple concomitant dissections tended to cluster on the same artery type rather than involving both a vertebral and carotid artery. Patients with ICAD had a less favorable 3-month functional outcome (modified Rankin Scale score>2, OR=3.99 [2.32-6.88]), but this was no longer significant after adjusting for baseline NIHSS score. Conclusion: In the largest published series of patients with CEAD, we observed significant differences between VAD and ICAD in terms of risk factors, baseline features, and functional outcome. © 2011 by AAN Enterprises, Inc.