Stapedius muscle excess movement of the stapes, helping to control the amplitude of sound waves from the general external environment to the inner ear Paralysis of the stapedius allows wider oscillation of the stapes, resulting in heightened reaction of the auditory ossicles to sound vibration. This condition, known as hyperacusis, causes normal sounds to be perceived as very loud. Paralysis of the stapedius muscle may result when the nerve to the stapedius, a branch of the facial nerve, is damaged, or when the facial nerve itself is damaged before the nerve to stapedius branches. In cases of Bell's palsy, a unilateral paralysis
Composition of the human body Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple bystander contaminants without function (examples: caesium, titanium), while many others are thought to be active toxics, depending on amount (cadmium, mercury, radioactives). The possible utility and toxicity of a few elements at levels normally found in the body (aluminium) is debated. Functions have been proposed for trace amounts of cadmium and lead, although these are almost certainly toxic in amounts very much larger than normally found in the body. There is evidence that