The internal carotid artery supplies:

• A. All of the inner cranial structures
• B. Muscles of the face
• C. Salivary glands
• D. Spinal cord

Answer: (A)

The key idea is that the internal carotid artery is the main source of blood for most structures inside the skull. After entering the skull, it gives branches such as the ophthalmic artery and the anterior and middle cerebral arteries, which supply the brain and the eye. That makes it responsible for the inner cranial structures.

Structures like the muscles of the face are supplied mainly by branches of the external carotid artery, not the internal carotid. The salivary glands receive arterial supply from branches of the external carotid as well, not predominantly from the internal carotid. The spinal cord is supplied mainly by the vertebral arteries, through the anterior spinal artery, rather than the internal carotid.

So, the internal carotid artery best accounts for the blood supply to the majority of intracranial (inner cranial) structures.