This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head & Neck, Subject name: Anatomy
True about vertebral artery - 
Select and explain. 
A. A branch of thyrocervical trunk, B. Enters skull through foramen magnum, C. Unite to form posterior cerebral artery, D. A small artery
B: Enters skull through foramen magnum
Answer: B: Enters skull through foramen magnum 
Explanation: Ans. is 'b' i.e., Enters skull through foramen magnum Vertebral arteryo It is the largest branch of subclavian artery.o Vertebra] artery traverses through vertebral triangle, foramina transversaria of upper six cervical vertebrae. suboccipital triangle, posterior atlanto-occipital membrane, vertebral canal, pierce duramater and arachnoid (Subarachnoid) and passes through foramen magnum to enter posterior cranial fossa. It gives following branches:-Cervical branches Spinal branches, muscular branches (to suboccipital muscle).Cranial branches Posterior inferior cerebellar artery, medullary artery, meningeal branches, anterior spinal artery, posterior spinal artery and both vertebral arteries unite to form basilar artery.