The tensor tympani muscle inserts into the malleus and is innervated by which nerve, while its primary physiological action is:

• A Facial nerve (VII); rotates handle of malleus medially, tensing tympanic membrane
• B Chorda tympani (VII); draws handle of malleus posteriorly, protecting the oval window
• C Medial pterygoid nerve (V3); rotates handle of malleus medially, tensing tympanic membrane ✓
• D Lesser petrosal nerve (IX); rotates stapes laterally, reducing transmission of low frequencies

Explanation

Tensor tympani is innervated by the medial pterygoid branch of the mandibular nerve (V3). On contraction it pulls the handle of the malleus anteromedially, effectively tensing the tympanic membrane and increasing its stiffness. This reduces transmission of low-frequency sounds and forms part of the acoustic reflex arc (though its role is secondary to stapedius). Stapedius is innervated by the facial nerve (VII) and has the dominant role in the stapedial reflex.

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.