Horner's syndrome secondary to traumatic pseudoaneurysms.

Since many clinical entities may result in Horner's syndrome, patients with this symptom complex must be evaluated for an underlying cause. We present two cases in which traumatic pseudoaneurysms along the oculosympathetic routes were discovered. Although vascular lesions of the internal carotid artery have been shown to cause Horner's syndrome [1-5], to the best of our knowledge there is no previous report of an internal mammary artery pseudoaneurysm as a cause. We also review the anatomy of oculosympathetic pathways , which are critical to understanding the location of lesions causing this common syndrome.