Vocal Fold Paralysis
The nerve to the voice box is called the 10th cranial nerve and exits from the brain through the bottom of the skull and down in the neck to the chest.
The main branch to the voice is called the recurrent laryngeal nerve and passes next to the lung then up behind the thyroid gland.
Any Injury to this nerve will result in a weak breathy voice. The most common surgery to do this is thyroid surgery but skull base, cervical disc and carotid artery surgery can also be responsible.
Sometimes the “superior” nerve which supplies the tensioning muscle of the voice is also affected and the patient will become very “breathy”.
CT SCANNING of the course of the nerve is essential and occasionally MRI if both sides are involved or both superior and recurrent laryngeal nerves are involved.
LEMG is an electrical test of the muscles of the voice, which will indicate which ones are involved and whether they are likely to recover.
In some cases, an explosive cough or overuse of the voice paralyses local branches of the nerve within the larynx. It will cause partial paralysis (known as PARESIS), bowed vocal fold and/or poor breathy voice with no power to it.
Various virus illnesses can do the same. Recovery may take up to six months or even longer.