Arteriovenous malformation is an abnormal collection or tangle of blood vessels connecting the arteries and veins in the brain. The arteries carry the oxygen-rich blood from the heart to the brain, and the veins carry the oxygen-depleted blood to the lungs and heart. The brain AVM disrupts this vital process as it is devoid of the capillary vessels that bridges the arteries and veins in general. Arteriovenous malformations are congenital in origin and can develop anywhere in the body but occurs most frequently in the brain and spinal cord.

The prevalence of brain AVM is less than 1 % in the population and has a slight male preponderance. Brain haemorrhage is the most common presentation of these malformations, and almost 50 % of them bleed due to rupture of an AVM. Some patients with AVM present with seizures (epileptic fit) and stroke (due to ischemia). Large high flow AVMs produce headache and sometimes vomiting due to raised intracranial tension.