Robert T. Sataloff, M.D., D.M.A. Vocal Fold Hypomobility Yolanda D. Heman-Ackah and Robert T. Sataloff ANATOMY AND FUNCTION with voice production except the cricothyroid muscles span the space OF THE LARYNX cricothyroid muscle. The joint space between the cricoid and thyroid car- between the arytenoid cartilage and tilages on the sides of the larynx. To- The movements of the vocal folds the cricoid cartilage is the cricoary- gether the thyroarytenoid muscle, its of the larynx are coordinated by the tenoid joint. It is critical that the joint specialized mucosal membrane, and activities of the muscles of the larynx, space between the arytenoid and its attachment onto the vocal process the cartilages of the larynx, and the cricoid cartilage is mobile and allows of the arytenoid cartilage are referred nerves that supply the muscles of the a full range of motion of the ary- to as the vocal fold or true vocal fold. larynx. l The larynx sits above the tenoids. If this cartilaginous joint be- The vocal folds come together and trachea and in front of the esophagus. comes immobile, the arytenoid carti- meet in the midline when the thy- The larynx has two identical sides that lage can not move well. Limited roarytenoid, interarytenoid, lateral form a mirror image of each other and mobility of the arytenoid cartilage im- cricoarytenoid, and cricothyroid mus- l is composed of cartilage, muscle, and pairs the mobility of the vocal folds. cles contract. These muscles help to mucous membranes. The muscles of the larynx attach bring the vocal folds together during The cartilage provides the struc- to the cartilages in different lo- swallowing and prevent the passage of tural support for the muscles and mu- cations. The main muscles of the lar- food particles and liquids into the tra- cous membranes similarly to the way ynx are the thyroarytenoids, the chea. Additionally, the laryngeal mus- in which the framework of a house posterior cricoarytenoids, the lateral cles contract to bring the vocal folds provides support for the walls and cricoarytenoids, the interarytenoids, together in voice production. When floors. The main cartilages of the lar- and the cricothyroids. Each side of air is pushed from the lungs past the ynx are the thyroid, cricoid, and ary- the larynx has a thyroarytenoid, a closed vocal folds, a sound is made. tenoid cartilages. The arytenoid carti- posterior cricoarytenoid, and a later- This sound is the voice. If the vocal lages sit on top of the cricoid cartilage al cricoarytenoid muscle. The inter- folds are able to make good contact, and serve as points of attachment for arytenoid muscles sit in the midline and if the movement of the mucosal all of the muscles that are involved of the back of the larynx, and the cover is normal, a clear sound is made. ϑουρναλ οφ Σινγινγ, Μαρχη/Απριλ 2002 ςολυμε 58, Νο. 4, ππ 321 − 327 Χοπψριγητ 2002 Νατιοναλ Ασσοχιατιον οφ 321 Τεαχηερσ οφ Σινγινγ Yolanda D. Heman-Ackah and Robert T. Sataloff When the cricothyroid and thy- After the superior laryngeal tient attempts to vocalize. The air roarytenoid muscles contract, they nerve branches, the vagus nerve from the lungs that is normally tense the vocal fold.l When there is a travels into the chest to supply neural trapped below the vocal folds during lot of tension on the vocal fold, a high- innervation to the heart, where it phonation is able to leak through this pitched sound is produced. When helps regulate heart rate and blood gap. The turbulent flow of air there is less tension on the vocal fold, pressure. While in the chest, the re- through the gap produces the sound lower-pitched sounds are produced. current laryngeal nerve separates that is perceived as breathiness. As When the posterior cricoarytenoid from the vagus nerve and courses air from the lungs continues to leak muscle contracts, it pulls the vocal back into the neck, where it enters through the vocal folds, prolonged folds open. The vocal folds open to the larynx. In the larynx, the recur- phonation becomes more effortful. allow the entrance of air into the air- rent laryngeal nerve supplies motor Many describe this sensation as vocal way when a breath is taken and to function to the thyroarytenoid, inter- fatigue. provide breaks between sounds dur- arytenoid, posterior cricoarytenoid, The vocal folds also help to pro- ing phonation. and lateral cricoarytenoid muscles. tect the lungs and the trachea from The larynx receives neural sup- The recurrent laryngeal nerve also aspiration of food and liquids during ply from two nerves, the superior la- supplies sensation to the vocal folds swallowing. If they are unable to ryngeal nerve and the recurrent la- and to the portions of the larynx and close completely during swallowing, ryngeal nerve. The superior laryngeal trachea below the vocal folds. aspiration may occur. If the sensation nerve supplies motor function to the of the vocal folds and trachea is cricothyroid muscle and sensation to normal, choking or coughing may oc- the parts of the larynx above the vo- SYMPTOMS OF VOCAL cur each time food or liquid is aspi- cal folds. The recurrent laryngeal FOLD HYPOMOBILITY rated. If the sensation is not working nerve supplies motor function to the correctly, aspiration may occur with- remaining muscles of the larynx and A patient who has decreased vo- out signs of choking or coughing, a sensation to the vocal folds and the cal fold mobility will likely experi- phenomenon commonly referred to ence problems with hoarseness, a parts of the larynx below the vocal 2 as "silent aspiration." Whether or not folds. breathy voice, and/or vocal fatigue. the sensation in the nerve is affected The recurrent laryngeal nerve Hoarseness is sometimes perceived depends on whether the mobility and the superior laryngeal nerve are because of abnormal strain in the problems are due to nerve dys- branches of the vagus nerve. Each of muscles around the larynx as the pa- function or other causes and on these nerves is paired, with one of tient tries to bring the vocal folds to- whether the sensory portions of the the pair on each side of the neck and gether. This excess muscle tension nerve are affected by the same prob- larynx. The vagus nerve branches di- may sometimes result in false vocal lem that is limiting the motor func- rectly off the brainstem, the portion fold phonation, which has a more tion of the nerve. of the brain at the base of the skull. raspy or hoarse quality than normal The vagus exits the base of the skull true vocal fold phonation. A breathy and enters the neck, where it branch- quality is produced as a result of air DIAGNOSIS OF VOCAL es twice. The superior laryngeal escape through the incompletely FOLD HYPOMOBILITY nerve is the first branch. It courses closed vocal folds. When there is into the larynx above the thyroid car- paresis (weakness) or paralysis (im- Patients with movement disor- tilage and divides into the internal mobility due to complete nerve dam- ders of the larynx may have com- and the external branches. The inter- age) of the vocal fold, the normal vo- plaints that range from hoarseness, nal branch supplies sensation to the cal fold must compensate for this breathiness with phonation, and vo- portions of the larynx above the vo- weakness by closing to the midline, cal fatigue to problems with swallow- cal folds. The external branch sup- and sometimes closing past the mid- ing, choking, shortness of breath, and plies motor function to the cricothy- line, to meet the other vocal fold. If it aphonia. The patient who has these roid muscle. is unable to do this, there is a gap complaints is generally evaluated by between the vocal folds when the pa the otolaryngologist (an ear, 322 LaryngoSCOPE nose, and throat doctor) or pain, although it may cause a slight lage to a lesser degree, resulting in laryngologist (an ear, nose, and discomfort in the nose. The patient is tilting of the larynx towards the side throat doctor who specializes in seated and awake during the exami- of the weak superior laryngeal nerve treating disorders of the larynx). The nation. The flexible laryngoscope and cricothyroid muscle. physician may ask the patient many al-lows the physician to see the If there are problems with both questions about the symptoms to larynx in its natural position, superior laryngeal nerves, there will help exclude other possible causes without the distortion that be limitations in the ability to pro- and to help narrow the potential list sometimes occurs with holding the duce a high pitch and in the ability to of problems. tongue forward for mirror and rigid stretch the vocal folds on both sides.2 After the physician has telescopic examinations. In viewing This diagnosis may be somewhat dif- completed taking a history of the the larynx in its natural position, the ficult, especially if both nerves are in- patient's problems, he/she will physician can assess changes in jured to the same degree. Both vocal examine the patient. The physical laryngeal muscle tension while the folds will have limitations in their examination will include a complete patient is talking or singing. There abilities to stretch, making the ability evaluation of all of the structures of are certain vocal maneuvers that the to see subtle abnormalities difficult the head and neck .3 This complete otolaryngologist/ laryngologist will for the examiner. examination is performed because ask the patient to perform during the Occasionally, with superior la- there are some disorders that affect flexible laryngoscopic examination. ryngeal nerve paresis, there is seen many different regions of the head These include various tasks of an abnormality in the ability of the and neck, and they all should be talking, singing, and whistling.3,4 vocal fold on the affected side to assessed.