The recurrent laryngeal nerve actually refers to two nerves designated by left and right side. These are connected to the left and right side vagus nerves, which begin at the brain stem and thread their way to approximately the middle of the body. Each one arises from the vagus nerve right near the aorta. The arrangement of each one as it moves up toward the neck is slightly different. Both end up near or behind the thyroid gland.
Some differences exist in the pathway each recurrent laryngeal nerve takes. The left nerve is longer and often twice as long as the right nerve. Approximate measurements in human anatomy are that left nerve is about 4.72 inches (12 cm). The extra length is often associated with greater potential for injury, and it does seem that damage to the left nerve is reported with greater frequency.
Essentially both nerves are responsible in part for controlling parts of the larynx and vocal cords, and there can be significant problems if either recurrent laryngeal nerve is damaged. Speech quality can definitely be affected significantly. There are three basic ways in which either nerve could become injured. A tumor along the nerve site might arrest its ability to function. Certain surgeries may result in damage to these nerves. In approximately a third of the cases where nerve damage is noted, there is no definable cause.
Since the recurrent laryngeal nerves on both sides are very close to the thyroid gland, one principal risk for surgical injury is surgical removal of the thyroid. Should a nerve become damaged, people might have a husky, throaty or whispering voice because the vocal cords will not meet each other to produce enough sound. Damage could be temporary or permanent, but it bears mention in any thyroid or other neck surgery as a potential risk since some cases of vocal cord paralysis are incurable, though using inserts to push the cords together may palliate the condition in others.
It is just as possible to damage the nerves from lower in the body. Chest surgery, especially near the aorta might result in a damaged recurrent laryngeal nerve too. Sometimes not only surgery can cause nerve damage. Instead, severe illness affecting the chest or throat could result in temporary or permanent impairment of a recurrent laryngeal nerve.
While most people might never need to know the reason for the existence of a recurrent laryngeal nerve, both of these nerves are important especially during head/neck/chest surgery of any type. Risk for potential damage is a good thing to discuss with a surgeon, though need for surgery in any of these areas often outweighs risk of injury to a nerve. Nevertheless, it is a topic of concern to many, since they want to recover from surgery with ability to speak in a normal voice intact.