Human Anatomy - Kotsan I. Y. 2009

Vestibulocochlear organ (organ of hearing and equilibrium)
Vessels and nerves of the organ of hearing and equilibrium

The Organ of Hearing and Equilibrium receives its Blood supply from several sources.

The External ear is supplied with arterial blood from branches of two Arteries—the superficial temporal and posterior auricular (both arising from the external carotid); the anterior wall of the osseous part of the external acoustic meatus and the tympanic membrane are supplied by the deep auricular arteries (derived from the maxillary artery).

Venous blood from the external ear drains into the posterior auricular vein (a tributary of the External Jugular Vein) and the anterior auricular Veins (tributaries of the retromandibular vein).

Lymph from the entire external ear drains into Lymph Nodes located anterior and posterior to the auricle.

The Middle ear is supplied by Branches of the external and internal carotid arteries: the anterior tympanic artery (a branch of the maxillary artery), the posterior tympanic and stylomastoid arteries (branches of the posterior auricular artery), the superior tympanic artery (a branch of the middle meningeal artery), the inferior tympanic artery (a branch of the ascending pharyngeal artery), and the caroticotympanic arteries (from the Internal Carotid Artery).

The VEINS OF THE middle ear accompany the corresponding arteries and drain into the pharyngeal venous plexus, the meningeal veins (tributaries of the Internal jugular vein), and the retromandibular vein.

Lymph from the middle ear drains partly into nodes on the lateral wall of the Pharynx and partly into the lymph nodes posterior to the auricle.

The internal ear is supplied by the labyrinthine artery (a branch of the Basilar artery), which accompanies the Vestibulocochlear nerve and gives off branches to the vestibule, semicircular canals, and cochlea.

Venous blood from the structures of the internal ear drains via the labyrinthine vein, the vein of the cochlear canaliculus, and the vein of the vestibular aqueduct into the superior petrosal sinus or directly into the internal jugular vein.

The nerves supplying the Organ of Hearing and Balance originate from multiple sources. Sensory innervation to the external ear is provided by branches of the trigeminal (auriculotemporal nerve), vagus (auricular branch), and great auricular nerves. The tympanic membrane receives branches from the auriculotemporal and vagus nerves, as well as the tympanic plexus, which is located in the mucous membrane of the tympanic cavity. The tympanic plexus is formed by sensory and parasympathetic fibers of the Glossopharyngeal nerve (tympanic nerve) and the Facial Nerve (communicating branch with the tympanic plexus), along with sympathetic fibers from the internal carotid plexus (caroticotympanic nerves). The tympanic plexus continues into the mucous membrane of the auditory tube, which also receives branches from the pharyngeal plexus. The Muscles Attached to the auditory ossicles are innervated by different sources as well: the stapedius Muscle receives its supply from the facial nerve, whereas the tensor tympani muscle is innervated by the mandibular branch of the Trigeminal nerve.