This video provides a histological examination of a laryngeal biopsy, differentiating between the true vocal cord and the false vocal cord (vestibular fold) based on their underlying tissue composition. Both folds are lined by non-keratinizing stratified squamous mucosa. The analysis identifies one fold as being predominantly composed of skeletal muscle fibers, while the other fold is characterized by an abundance of serous and mucous glands. This structural difference is used to definitively classify the muscle-dominated structure as the true vocal cord and the gland-dominated structure as the false vocal cord.
Histological Differentiation of True and False Vocal Cords
0:05 Initial Histology: The specimen presents two distinct folds (ridges), both lined by non-keratinizing stratified squamous mucosa.
0:26 Composition of Fold 1 (Left): The contents of the first fold are predominantly classical skeletal muscle fibers, where the nuclei are situated at the periphery of the fiber.
0:47 Composition of Fold 2 (Right/Other): The second fold contains less skeletal muscle but features a predominance of serous and mucous glands.
1:07 Gland Appearance: The speaker details the appearance of the glands, noting that the mucous elements appear grayish, with nuclei pushed towards the periphery, while the serous elements stain a more normal pinkish color.
2:06 The Question: Given the specimen is taken from the larynx, the folds must represent the true vocal cord (vocal fold) and the false vocal cord (vestibular fold).
2:35 Key Takeaway (True Vocal Cord): The fold characterized by the presence of abundant skeletal muscle is identified as the true vocal cord (or vocal fold).
2:39 Key Takeaway (False Vocal Cord): The fold characterized by the predominance of serous and mucous glands is identified as the false vocal cord or vestibular fold.