11/13- Voice Lecture 5 Flashcards
(13 cards)
What is phonation?
- results from the creation of a vibrating column of air.
- Oscillation of the vocal folds depend on certain “biophysical conditions” that is necessary for phonation
What are the four aspects of phonation?
- Glottal configuration: vocal fold size; shape and approximation
- Aerodynamic changes in airflow and surface pressures
- Changes in tension of the vocal folds
- Changes in elasticity, density, and viscosity of structures
What does degree of adduction influence?
quality of voice
What are some deviations (problems) of laryngeal approximation ?
resistance may be so great that aerodynamic process needed to set the folds in motion are beyond respiration system capability.
This may occur when folds are not adducted enough or when they are adducted too tightly.
What are some neurological issues that can occurs with adduction patterns during intentional phonation?
- absence of vocal fold adduction to partial adductions; possibly due to brainstem injury
- vocal fold paralysis or paresis (weakness) may be unilateral or bilateral
- may be due to adductor muscle damage or recurrent laryngeal nerve damage- branch of Vagus (Xth cranial nerve)
What is vocal fold paralysis?
disruption of the neuromuscular innervation of the muscles controlling vocal fold movement.
What can cause unilateral or bilateral vocal fold paralysis?
- concomitant disease processes
- idiopathic issues (no known cause)
- neuritis (inflammation of a nerve)
- vagal recurrent laryngeal nerve (RLN)
- superior laryngeal nerve (SLN) lesions
- trauma
What can cause immobile vocal folds?
- mechanical/paralytic fixation
What is the result of bilateral vocal fold immobility (BVFI)?
Can be as a result of:
- a primary neurological disorder
- metabolic origin
- iatrogenic (dr. induced) complications of surgery or intubation.
- This type of paralysis occurred in the past more frequently post thyroidectomy. Per Andrews more VFIs currently are caused by malignancies and nonsurgical trauma than in the past
What are some causes of vocal fold immobility?
- Carcinoma (bronchi, lung, larynx, thyroid, esophagus, carotid, nasopharynx)
- Central Nervous system Lesions; Infections (e.g, tuberculosis etc..)
- Diseases ( e.g.,cardiac, autoimmune);
- Inflammatory Conditions ( e.g., rheumatoid arthritis);
- Trauma ( e.g, neck surgery, blunt, gunshot, intubation, TBI)
What nerve is the chief player?
Vagus
What is the Vagus innervation?
- Vagus comes via lateral surface of the medulla; after emerging from the skull;
- vagus divides into left and right; and into three branches
- Pharyngeal branches of the vagus nerve travel down between the external and internal carotid arteries to innervate the pharyngeal constrictor muscles
- They then subdivide and join branches from the sympathetic trunk; and glossopharyngeal and external laryngeal nerves to make the pharyngeal plexus
- The plexus provides innervation to the pharynx and muscles of the velum. Vagus nerve lesions above this point, can cause adductor paralysis of the larynx and paralysis of the velopharyngeal muscle
After the superior laryngeal nerve branches split into the internal and external laryngeal nerve branches, what do they do?
splits into two additional branches which contain afferent (sensory) fibers
- upper branch supplies the mucous membranes of the epiglottis and vestibule of the larynx;
- lower branch supplies the mucous membrane of the arytenoid cartilages and the dorsum of the arytenoid cartilages.
- There is a motor supply to the cricothyroid; lesions at this level cause paralysis of the cricothyroid muscle
