Atypical anastomosis of laryngeal nerves

Abstract

The larynx and its associated structures derive their chief source of innervation from the superior and recurrent laryngeal nerves. Surgery of the larynx requires a sound knowledge of the normal anatomy as well as variations that may be encountered in this region. We report the presence of rare communications between the right external and internal laryngeal nerves as well as between the right external and inferior laryngeal nerves via a thyroid foramen. In addition, we report on bilateral innervation of the respective ipsilateral aryepiglottic, transverse, and oblique arytenoid muscles by the internal laryngeal nerve, which is contrary to the classical descriptions of this nerve. The anatomic features are described and clinical implications are highlighted.

The thyroid foramen

“…Partab et al displayed a very rare case of a double neural anastomosis threading through the TF. Specifically, the proximal neural loop was formed between the ebSLN and ibSLN, whereas the distal loop was formed between the ebSLN and the ILN (Partab et al, ). On the contrary, Liu et al found the TF crossed over by an aberrant branch of the SLA in all cases (Liu et al, ).…”

“…Little is written regarding the accurate topographic anatomy of the TF, but the oblique line which connects the superior and inferior thyroid tubercle of the thyroid lamina is the most usual topographic landmark for its localization. Some authors locate the TF at the oblique line of the thyroid cartilage (Tanaka et al, ; Partab et al, ; Rusu et al, ), while there are observations that it is more frequently found anterior to the oblique line (Ramsaroop et al, ). Harjeet and Jit, commented about the TF topography and relation to its content.…”

Laryngeal nerve “anastomoses”

“…5A). Partab et al [15] also observed a single case in which the right internal laryngeal nerve communicated with the external laryngeal nerve through the thyroid foramen.…”

Intrinsic neuroendocrine cells in the outer wall of the human pyriform recess

“…The pyriform recess (Recessus piriformis) of the hypopharynx is supplied with vagal fibers via the laryngeal nerves and their anastomoses (Liebermann-Meffert et al 1999;Partab et al 2006;Migueis et al 1989;Rusu et al 2011a). Microganglia of the pharyngeal wall were assessed by Remak in 1840 (Furness and Costa 1987); since then, few studies have evaluated the neural content of the pharyngeal wall (Shimazaki et al 1998).…”