<prompt> Common carotid artery divides at the level ofHyoid boneCricoid cartilageSuperior border of thyroid cartilageInferior border of thyroid cartilage  <response>: Ans. is c i.e. Superior border of thyroid cartilage Common carotid artery ends at the level of upper border of the thyroid cartilage by dividing into external internal carotid arteries Also remember the following imp. levels Sternal angle- costal cartilage of 2nd rib, T4T5IV disc Xiphoid process- T9 Tracheal bifurcation- T4T5 IV disc Trachea extends from- C6 to T5 Arch of aorta begins and ends at- T4 Aortic opening in diaphragm- T12 Esophageal opening in diaphragm- T10 Vena caval opening in diaphragm- T8 Thoracic duct crosses from Rt to Left- T5 Splenic axis- 10th rib Celiac trunk arises- T12L, IV disc Superior mesenteric artery arises- LI Renal arteries- L1L2 Inferior mesenteric artery- L3 Aorta ends by bifurcating into common iliac arteries- L4 IVC begins at- L5 Umbilicus- L3L4 