Question

Which of the following passes through the foramen magnum?

• A. Vertebral artery
• B. Sympathetic chain
• C. XIth cranial nerve
• D. Internal carotid artery

Hint:

Think of the gateway where the medulla becomes the spinal cord, and which artery climbs in there.

Answer 1

The Correct Option is A

Step 1: The foramen magnum is the large opening in the occipital bone that connects the posterior cranial fossa with the vertebral canal. Several structures pass through it.

Step 2: The structures passing through the foramen magnum are: the medulla oblongata with its meninges, both vertebral arteries, the anterior and posterior spinal arteries, the spinal (ascending) part of the accessory nerve, the apical ligament of the dens, the tectorial membrane, and the dural veins.

Step 3: The vertebral artery enters the cranial cavity by passing through the foramen magnum, so option A is correct.

Step 4: Why the others are wrong. The sympathetic chain runs in the neck and thorax along the vertebral column and does not pass through the foramen magnum. The XIth cranial nerve (accessory) is tricky: its spinal root ascends through the foramen magnum, but the accessory nerve as a whole exits the skull through the jugular foramen, so naming the cranial nerve XI as a foramen magnum structure is the distractor here. The internal carotid artery enters the skull through the carotid canal, not the foramen magnum.

Answer: A. Vertebral artery