In the middle ear, the tensor tympani muscle inserts on the manubrium of the malleus and is supplied by which nerve? What is its primary function?

• A Facial nerve (VII); reflexively contracts in response to loud sounds to protect the cochlea
• B Glossopharyngeal nerve (IX); increases middle ear impedance during swallowing
• C Mandibular nerve (V3); tenses the tympanic membrane to dampen sound transmission during chewing ✓
• D Chorda tympani; modulates Eustachian tube tone

Explanation

The tensor tympani is innervated by the medial pterygoid nerve, a branch of the mandibular division of the trigeminal nerve (V3). It pulls the manubrium of the malleus medially, tensing the tympanic membrane and reducing vibration amplitude. Its primary evolutionary role is to dampen low-frequency masticatory sounds. The stapedius muscle (CN VII) is the one involved in the acoustic reflex to loud sounds.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.