2026 Poster Presentations
P485: REVISITING THE TYMPANIC ARCADE IN SKULL BASE SURGERY
Kyoichi Tomoto, MD1; Kentaro Watanabe2; Michihiro Tanaka1; Yuichi Murayama2; 1Kameda Medical Center; 2The Jikei University School of Medicine
In skull base surgery, a precise understanding of the external carotid artery system is essential. The tympanic arcade has been described angiographically, but its detailed anatomical relationship with adjacent structures remains unclear. Traditionally, vessels have been studied on angiography and nerves in cadaveric dissection, creating a gap in understanding. This study aimed to clarify the three-dimensional anatomy of the tympanic arcade by focusing on its vascular components in cadaveric dissection.
The tympanic arcade was conceptually divided into two main components to simplify its complex vascular network: (1) the stapedial artery and its remnants, and (2) the facial arcade, consisting of arteries accompanying the facial nerve.
(1) Stapedial artery component: The stapedial artery originates from the hyoid artery of the second aortic arch and passes between the crura of the stapes. It gives rise to upper and lower branches supplying the orbit and maxillomandibular region. With its regression, blood flow reverses from extracranial to intracranial, leaving remnants such as the superior and anterior tympanic arteries. Occasionally, the stapedial artery persists, or collateral channels through the inferior tympanic artery from the ascending pharyngeal artery develop, forming an aberrant internal carotid artery. The proximal portion of the stapedial artery often remains as the carotico-tympanic artery, entering the tympanic cavity.
(2) Facial arcade component: The facial arcade is composed of arteries that run alongside the facial nerve. The posterior tympanic artery accompanies the chorda tympani through the posterior canaliculus; the anterior tympanic artery passes through the petrotympanic fissure with the chorda tympani; the superior tympanic artery travels with the lesser petrosal nerve through the hiatus canal; and the superficial petrosal artery accompanies the greater petrosal nerve from the geniculate ganglion. The internal auditory artery, a branch of the anterior inferior cerebellar artery, anastomoses with the stylomastoid artery at the tympanic segment of the facial nerve, forming part of this arcade.
The tympanic cavity was also schematically represented as a cube to spatially integrate these vessels in relation to adjacent nerves and bony landmarks. Representing the tympanic cavity as a cube enables a simplified understanding of the superior, inferior, anterior, and posterior tympanic arteries, as well as the carotico-tympanic artery. Integrating cadaveric vascular findings with known neural anatomy helps clarify the three-dimensional organization of the tympanic arcade.