the canal extending from the opening in the external ear to the tympanic membrane.
- External capsule
external capsule n. A thin lamina of white substance in the brain that separates the claustrum from the putamen.
- External carotid nerve
external carotid nerve n. Any of the sympathetic nerve fibers extending upward from the superior cervical ganglion along the external carotid artery, forming the external carotid plexus.
- External carotid plexus
external carotid plexus n. An autonomic plexus that is formed by the external carotid nerves, surrounds the external carotid artery, and gives origin to a number of secondary plexuses along the branches of the external carotid artery.
- External carotid steal syndrome
external carotid steal syndrome n. Brief ischemic attacks that are marked by dizziness and loss of balance and are caused by insufficient blood supply to the vertebral and basilar arteries.