Stapedius muscle

Stapedius muscle is the smallest skeletal muscle in the human body. It is located in the middle ear, and its primary function is to stabilize the smallest bone in the body, the stapes.

Etymology

The term "stapedius" is derived from the Latin word "stapes," which means "stirrup." This is a reference to the shape of the stapes bone, which the stapedius muscle controls.

Anatomy

The stapedius muscle originates from the posterior wall of the tympanic cavity, and inserts into the neck of the stapes. It is innervated by the facial nerve (cranial nerve VII).

Function

The primary function of the stapedius muscle is to dampen the vibrations of the stapes by pulling on the neck of this bone. This action prevents excessive movement of the stapes, helping to control the amplitude of sound waves from the environment as they pass into the inner ear. In doing so, the stapedius muscle protects the inner ear from potential damage caused by excessively loud noises.

Clinical significance

Damage to the stapedius muscle or its nerve supply can result in a condition known as hyperacusis, where sounds are perceived as much louder than they actually are. This can be caused by a number of factors, including Bell's palsy, a condition that causes temporary weakness or paralysis of the muscles in the face.

Related terms

• Middle ear: The part of the ear that contains the stapedius muscle.
• Stapes: The bone that the stapedius muscle controls.
• Hyperacusis: A condition that can result from damage to the stapedius muscle or its nerve supply.

Stapedius muscle Resources
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