It is somewhat dilated at its origin, and this dilatation is called the superior bulb.
It also has a common trunk into which drains the anterior branch of the retromandibular vein, the facial vein, and the lingual vein.
It runs down the side of the neck in a vertical direction, being at one end lateral to the internal carotid artery, and then lateral to the common carotid, and at the root of the neck, it unites with the subclavian vein to form the brachiocephalic vein (innominate vein); a little above its termination is a second dilatation, the inferior bulb.
CT: Chorda tympani; I: Incus; JB: Jugular bulb; LSC: Lateral semicircular canal; M: Malleus; PSC: Posterior semicircular canal; S: Stapes; SM: Stapedius muscle; SSC: Superior semicircular canal; VIIms: mastoid segment of VII cranial nerve; VIIts: tympanic segment of VII cranial nerve.
AE: arcuate eminence; AICA: anteroinferior cerebellar artery; JB: jugular bulb; SC: semicircular canals; SCA: superior cerebellar artery; SPV: superior petrosal vein; SS: sigmoid sinus; VA: vertebral artery.