Clinical diagnosis
Case 170
【Progress】
Fortunately, she never experienced hoarseness. Her dislocated arytenoid cartilage was fixed, indicative of no trouble to make voices. She was under watchful observation and she came routinely to our hospital for her self-immune disease.
【Discussion】
There are several cartilages in the larynx: thyroid cartilage, cricoid cartilage, arytenoid cartilage, corniculate cartilage and cuneiform cartilage. Thyroid cartilage is the anterior armor to defend the traumatic attack from the frontal direction. Cricoid cartilage is the posterior armor to defend the pressure from the dilated esophagus by food. Corniculate cartilage at the top of arytenoid cartilage and cuneiform cartilage laterally adjacent to the corniculate cartilage. Both cartilages function as the receiver of epiglottis tip when epiglottis closes.
Meanwhile, arytenoid cartilages are present as a pair below the corniculate cartilage. Its configuration is like a trigonum but not a simple one. It has several faces and plays a role of critical function (1, 2). An arytenoid cartilage connects a vocal cord and has attachments of several muscles. Namely, an arytenoid cartilage plays two roles; helping to make voices: helping to close the tracheal lumen when swallowing food.
There are six small muscles who attach arytenoid cartilage or arise from arytenoid cartilage; vocal (thyroarytenoid) muscle; lateral cricoarytenoid muscle; posterior cricoarytenoid muscle; transverse arytenoid muscle; oblique arytenoid muscle; aryepiglottic muscle. Vocal fold consists of vocal cord and vocal muscle. Both of bilateral vocal cord and vocal muscle arise from arytenoid cartilage to attach to thyroid cartilage. They function to make a voice. Lateral cricoarytenoid muscle and posterior cricoarytenoid muscle not only fix arytenoid cartilage with cricoid cartilage but also function to open or close glottis. In short, contraction of lateral cricoarytenoid muscle leads to close glottis while contraction of posterior cricoarytenoid muscle leads to open glottis. Transverse arytenoid muscle fixes right and left arytenoid cartilage. Oblique cartilage configures like sleeves tucked up. It connects aryepiglottic muscle and posterior cricoarytenoid muscle. They connect and work together to open or close epiglottis and glottis by contraction or relaxing.
Arytenoid dislocation is known to occur after tracheal intubation (2-10). Left-sided arytenoid cartilage is susceptible to be damaged because the number of anesthesiologists with right-handed is greater than that with left-sided (6-9). The unreasonable and/or forceful maneuver of tracheal tube using right hand may cause the tube contact to the left corniculate cartilage connected to the arytenoid cartilage and injure it. Endoscopic examination reveals the existence vocal folds, corniculate cartilage and cuneiform cartilage. Our case was picked up by endoscopic examination which showed left swollen corniculate cartilage with redness, biopsy revealed no malignancy and CT demonstrated the forward dislocation of the left arytenoid cartilage.
【Summary】
We present a sixty nine-year-old female whose left arytenoid cartilage was found to be swollen with redness during endoscopic examination. She had caesarean operation under general anesthesia at her youth. Neck CT showed the dislocation of the left arytenoid cartilage. It is borne in mind that there are five cartilage in the larynx; thyroid, cricoid, corniculate, cuneiform and arytenoid. A pair of arytenoid cartilage plays a critical role of making a voice and opening or closing glottis and epiglottis. There six small muscles arising from or attaching to arytenoid cartilage. Vocal muscle (Thyro-arytenoid) muscles make voice production, lateral cricoarytenoid muscle closes glottis, posterior cricopharyngeal muscle opens glottis, arytenoid muscle connects right and left arytenoid muscle. Further, aryepiglottic muscle, oblique muscle and posterior cricoarytenoid muscle work together to open or close epiglottis. Arytenoid dislocation occurs by forceful tracheal intubation and the left-side dislocation occurs more than the right-sided because of the right-handed anesthesiologists. Our patient had received caesarean operation under general anesthesia previously at her youth. Neck CT showed forward dislocation of the left arytenoid cartilage.
【References】
1.Andaloro C, La Mantia I. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Feb 7, 2019. Anatomy, Head and Neck, Larynx Arytenoid Cartilage.
2.Schmalfuss IM, et al. Arytenoid cartilage sclerosis: normal variations and clinical significance. (1998) AJNR. American journal of neuroradiology. 19 (4): 719-22.
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2019.11.20