The tympanic plexus lying over the promontory of the medial wall of the middle ear is formed chiefly by which nerve?

• A Nerve to stapedius
• B Auricular branch of the vagus nerve (Arnold nerve)
• C Greater petrosal nerve
• D Tympanic branch of the glossopharyngeal nerve (Jacobson nerve) ✓

Explanation

Jacobson nerve, the tympanic branch of CN IX, enters the middle ear through the tympanic canaliculus and forms the tympanic plexus on the promontory along with caroticotympanic sympathetic fibres. It supplies sensory innervation to the middle ear mucosa. The Arnold nerve supplies skin of the concha and external canal, while the greater petrosal nerve passes through the middle cranial fossa, not the tympanic plexus.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.