[Laryngeal nerves. A histomorphometric and cartographic study].

Major difficulties in laryngeal reconstruction are due to laryngeal nerves. A study was conducted of 100 larynges from fresh subjects after vascular injection. Vascularization of superior laryngeal nerves is derived essentially from superior laryngeal and ascending pharyngeal arteries. Inferior laryngeal nerves obtain their vascular supply from inferior thyroid and main carotid arteries. Histomorphometric study of laryngeal nerves used semi-automatic techniques: microscope, numerical table, computer, printer. The number of fibers per nerve varied between 511 and 2.244, the number of nerve fasculi between 3 and 14, and the diameter of myelinated fibers between 2 and 12 micron. Fibers of left inferior laryngeal nerve had a mean diameter (8.9 to 10.2) greater than those of right inferior laryngeal nerve (5.1 to 5.2 micron). Nerve tissue represented 60% to 66% of total. The left recurrent was longer than right nerve but had larger fibers providing more rapid conduction. Cartography of laryngeal nerves from 2 mm serial sections confirmed their plexis structure, this study providing new and objective precisions on laryngeal nerve structure.