Most common cause of dissecting hematoma is

Aoic dissection occurs when blood splays apa the laminar planes of the media to form a blood-filled channel within the aoic wall.Aoic dissection occurs mainly in two age groups: (1)men aged 40 to 60 with antecedent hypeension (more than 90% of cases); and (2) younger patients with connective tissue abnormalities that affect the aoa.Robbins Basic pathology, 9th edition, pg no.346