This section is from the book "Anatomy Of The Arteries Of The Human Body", by John Hatch Power. Also available from Amazon: Anatomy of the Arteries of the Human Body, with the Descriptive Anatomy of the Heart.
The Posterior Auricular Artery is one of the smallest branches of the external carotid: it arises in the substance of the parotid gland, nearly opposite the apex of the styloid process, and ascends along the superior margin of the posterior belly of the digastric muscle, till it arrives at the interval between the external auditory canal and mastoid process, where it divides into its two terminating branches, an anterior and posterior aural.
The posterior auricular artery gives off the following branches:—
Stylo-mastoid. Anterior, and Posterior Aural.
The Stylo Mastoid Branch enters the stylo-mastoid foramen, and after supplying the aqueduct of Fallopius, the tympanum and semi-circular canals, it terminates by anastomosing with a branch of the middle meningeal artery which enters by the hiatus Fallopii.
The Anterior Aural Branch is distributed to the internal or deep surface of the pinna.