<prompt> Which of the following represent the commonest variation in the aeries arising from the arch of aoa?Absence of brachiocephalic trunkLeft veebral aery arising from the archPresence of retroesophageal subclan aeryleft common carotid aery arising from brachiocephalic trunk  <response>: Most common anomaly of the aoic arch seen in 10-20 individuals is characterized by the origin of the left common carotid aery from the brachiocephalic innominate trunk. Other common anomalies include: A four vessel arch with separate origins for the right common carotid and right subclan aeries 2.5, Origin of the left veebral aery directly from a four vessel aoic arch typically between the ostia of the left common carotid and subclan aeries 2.4- 5.8. Ref: Gray;s anatomy text book of anatomy BD chaurasia 21st Ed. 