The tensor tympani tenses the eardrum by pulling the malleus medially. It forms part of the acoustic reflex (along with stapedius) that protects the inner ear from loud sounds. It is innervated by V3 (not facial nerve — unlike stapedius).
| Origin | Cartilaginous and bony walls of the Eustachian tube and the greater wing of the sphenoid |
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| Insertion | Manubrium (handle) of the malleus — via a tendon that turns 90 degrees at the processus cochleariformis |
| Nerve Supply | Medial pterygoid nerve — branch of mandibular nerve (V3) |
| Blood Supply | Middle meningeal artery branch |
| Actions | Tenses the tympanic membrane — reduces its vibration amplitude; Dampens loud sounds in coordination with the stapedius (acoustic reflex) |
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The tensor tympani participates in the acoustic startle reflex alongside stapedius. Myoclonus of the tensor tympani produces a low-frequency thumping tinnitus synchronous with contractions, distinct from stapedius myoclonus (which produces a clicking tinnitus). EMG differentiation identifies the affected muscle. Tensor tympani tenotomy is rarely performed for refractory tinnitus.
Not palpable — assessed by tympanometry (tympanic membrane compliance changes during acoustic reflex) and EMG.
Involuntary tensor tympani contractions producing a low-frequency thumping tinnitus, managed by muscle relaxants or tenotomy in refractory cases.
