The tensor tympani muscle is innervated by the medial pterygoid nerve (a branch of V3) and attaches to the malleus. Contraction of the tensor tympani results in:

• A Stiffening of the ossicular chain by pulling the stapes away from the oval window
• B Relaxation of the tympanic membrane to protect against low-frequency sounds
• C Stiffening of the ossicular chain by pulling the malleus handle medially and anteriorly ✓
• D Contraction of the stapedius muscle via a crossed reflex arc

Explanation

The tensor tympani runs from the auditory tube cartilage, through the semicanal, and inserts on the malleus handle at the umbo. Its contraction pulls the malleus medially and anteriorly, increasing tension in the tympanic membrane and stiffening the ossicular chain — attenuating transmission of low-frequency sounds. The stapedius (innervated by the facial nerve) contracts in the acoustic reflex to stiffen the stapes at the oval window. Both constitute the middle ear acoustic 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.