Intrinsic muscles and distribution of the recurrent laryngeal nerve in the pig larynx

Abstract

To use the pig larynx in studies of laryngeal reinnervation, it is essential to have a clear understanding of its anatomy. We aimed to define the macroscopic anatomy of the intrinsic muscles and the course of the recurrent laryngeal nerve (RLN) in the pig larynx. Twelve large white pig larynges were used. Five larynges were preserved in formalin, then dissected to study the anatomy of the intrinsic muscles. Seven larynges were stained using the modified Sihler's staining technique, which results in nerves being stained dark purple while the remainder of the larynx is rendered translucent. The intrinsic muscles of the pig larynx were similar to those in the human. The RLN gives off a branch that enters the posterior cricoarytenoid muscle (PCA) on its deep surface and supplies the entire muscle, although the branching pattern of the nerve within the muscle varies considerably. These results facilitate detailed reinnervation studies in the pig laryngeal transplant model.

Implementation of a program for surgical education in laryngology

“…Structurally, pig larynges also have a false and true vocal fold separated by a ventricle 15 but differ with a single muscular compartment posterior cricoarytenoid muscle. 17 Furthermore, the lamina propria in a pig vocal fold is made of two layers, 15,16 and creation of a microflap is hindered by submucosal glands in the glottis. 16 While pig vocal folds are similar to human vocal folds, Garrett et al found the dog vocal fold to be most similar to a human vocal fold based on histologic analysis and location of a microflap plane of elevation.…”

The larynx as an immunological organ: immunological architecture in the pig as a large animal model

“…One successful laryngeal transplant has been performed on a human subject [13], and the patient continues to do well in terms of speech and swallowing 7 years later ( [14]; Strome 2005, personal communication). Limited re-innervation did occur in this patient, and the problem of functional restoration is under study in several human and animal models, including the pig [15][16][17]. However, several questions regarding long-term survival and immunosuppression need to be answered before routine clinical use can be advocated.…”

Investigation of Experimental Wound Closure Techniques in Voice Microsurgery

“…Based on our experience with pig models, the dimensions of the larynx in a 30 to 40 kg pig are similar to that of the adult human (Garrett, Coleman et al 2000;Jiang, Raviv et al 2001). The vocal folds have a similar configuration, and the intrinsic muscles and distribution of the recurrent laryngeal nerve is similar as demonstrated by detailed dissections of cadaveric porcine laryngeal neuromuscular anatomy (Knight, McDonald et al 2005). Other phonatory characteristics such as rotational mobility of the cricothryoid joint, and relative size and innervation of the cricothyroid muscle have also been studied and found to be similar to that of humans (Jiang, Raviv et al 2001); although these features are not of direct relevance to endoscopic laryngeal microsurgery.…”

“…The presence of a superior and inferior fold could relate to the thyroarytenoid muscle having two separate bellies (Knight, McDonald et al 2005). It has been suggested that the inferior fold is the true vocal fold and the superior fold is akin to the ventricular fold in humans.…”