MCQ IN MEDICINE

Detailed explanation-1: -During the fourth and fifth weeks of embryological development, when the pharyngeal arches form, the aortic sac gives rise to arteries – the aortic arches . The aortic sac is the endothelial lined dilation just distal to the truncus arteriosus; it is the primordial vascular channel from which the aortic arches arise.

Detailed explanation-2: -Together with segments of the dorsal aortae, the distal portions contribute to formation of the internal carotid arteries. The left arch of the fourth pair forms the segment of normal left aortic arch between the left common carotid and subclavian arteries.

Detailed explanation-3: -It originates from the left ventricle of the heart anterior to the pulmonary artery before arching posteriorly and descending along the posterior mediastinum. It descends to the level of the L4 vertebral body where it bifurcates into the left and right common iliac arteries.

Detailed explanation-4: -Brachiocephalic trunk: also called the brachiocephalic artery, is the first and largest artery that branches off the aortic arch.