Acute arterial emergencies can arise from direct traumatic injury to the artery or be spontaneous. This article emphasizes the various presentations of arterial emergencies. These include acute arterial occlusions; excessive bleeding; and hematoma formation caused by penetrating arterial wall injuries, pseudoaneurysms, and arteriovenous fistulas. The broad category of arterial occlusions includes traumatic lacerations, embolizations, and arterial dissections. Modern ultrasound equipment is a rapid and convenient imaging approach in many of these clinical scenarios. In combination with MR angiography and CT angiography, these noninvasive tests can diagnose the presence of most arterial injuries, and be used to measure their impact.