Basic Lesions

The basic lesion in cervical artery dissection is an intramural haematoma in the vessel wall. This may occur as the result of two mechanisms:

• Haemorrhage from the vasa vasorum (Fig 1). The subsequent intramural haematoma can narrow the vessel lumen or cause an aneurysmal dilatation
• A tear in the intima of the vessel (Fig 2). This gives rise to an intimal flap and subsequent intra-vascular thrombosis

Fig 1: Haemorrhage from the vasa vasorum	Fig 2: Tear in the intima of the vessel with a blood clot at the site of the tear