The intramuscular nerve supply of the human lateral cricoarytenoid muscle.

The lateral cricoarytenoid (LCA) muscle is one of the adductors of the vocal cords; however, some investigators believe that the lateral edge of the muscle may be involved in abduction. The possibility of functionally distinct compartments within the LCA was investigated by observing the pattern of the intramuscular nerve supply. This technique has previously clearly demonstrated neural compartments in the posterior cricoarytenoid, thyroarytenoid and cricothyroid muscles. Five adult human larynges were processed by the Sihler's stain which clears all soft tissue while counterstaining the nerves. The results of our study showed that the innervation pattern of the human LCA muscle is composed of a homogenous nerve plexus localized to the middle region of the muscle. This pattern correlates with the location of motor endplates described by prior investigators. The consistent neural pattern suggests that the LCA is composed of a single neuromuscular compartment.