Neurogenic Voice Disorders-cranial Nerves

Trigeminal- motor innervation= muscles of mastication, sensory=tactile sensations of the nose and oral mucosa

Facial- motor innervation= facial muscles, sensory= taste in the anterior 2/3's of the tongue and sensation to the soft palate

Acoustic- carries sensory info to Heschl's gyrus in the temporal lobe (primary auditory cortex)

Glossopharyngeal- motor= superior pharyngeal constricotr and syopharyngeus muscles, sensory= taste in posterior 1/3 of the tongue and sensation to the fuases, tonsils, pharynx, and soft palate.

Vagus-controls autonomic nervous system involving thoarcic and abdominal viscera. Branches= Superior Laryngeal Nerve (SPN) and Recurrent laryngeal nerve (RLN). Vagus- MOtor=innervation of pharynx and larynx, velum, base of tongue, superior, middle, and inferior pharyngeal constricots, larynx, and autonomic ganglis of the thorax. (affecting respiratory aspcets of phonation)

Spinal Accessory- motor=innervation of the neck accessoyr muscles. 2 sections= cranial portion and spinal portion. Cranial portion- innervates levator veli palatini and uvula. Spinal portion- innervates major muscles of the neck such as the sternocleidomastoid and the trapezius muscles. Lesions to cranial nerve XI=problems of resonance because of the contribution to respiration of the neck accessory muscles.

Hypoglossal- motor=extrinsic and intrinsic muscles of the tongue, some neck strap muslces. Muscles it innervates: omohyoid, sternothyroid, styloglossus, hyoglossus, genioglossus, geniohyoid, sternohyoid, all instrinsic tongue muslces. Hypoglossal nerve positions the larynx, depression or elevation of the total laryngeal body and is essential for all intrinsic movements of the tongue. Impact on voice= resonance and quality.

Internal and external Internal branch=snesory innervation to the mucous membrane at the base of the tongue and to the mucous membrane of the supraglottal larynx. External branch-motor innervation to part of the lower pharyngeal constrictor and to the cricothyroid muscles.

It is an intrinsic laryngeal muscle. It is paired. Divided into 2 parts, the recta and the obliqua. Contraction increases the distance between the cricoid and thyroid cartilages, increasing the length of the vocal folds= rise in pitch. Also, has an adduction action.

Lesions are rare, often related to viral neuropathy. Primary symptom=inability to raise vocal pitch. In unilateral CT paralysis there may be extreme hoarseness and occasional diplophonia.

Branches off the Vagus below the level of the larynx. almost at the level of the middle trachea. 3 branches. RLN is vital to the abductory-adductory function of the larynx as it innervates the 5 intrinsic muslces of the larynx. (thyroarytenoid,posterior cricoarytenoid, lateral cricoarytenoid, transverse arytenoids, oblique arytenoids.

It is the main mass of the vocal fold. Originates in the anterior commissure. Medial portion of the TA is the vocalis muscle inserting in the vocal process of the arytenoid. Thyromuscularis= the larger muscle ortion of the TA. TA is a primary valve in airway protection. Also, the vibrating mass=phonation. Changes in pitch are related to changes in tension. TA contraction also contributes to medial vocal fold adduction.

Flaccid paralysis resulting from cutting or trauma to the RLN = vocal fold atrophy resulting in weakness in vocal fold papproximation, midfold bowing and dysphonia. Subtle changes of pitch variation will also be compromised with lack of TA innervation

Paired. It is the lone abductor muscles of the vocal folds. When it contracts, it rocks and lsides the arytenoid, parting the arytenoids and abducting the vocal folds.

Primary symptom=inability to open the glottis on the involved side, creating a unilateral abductor paralysis