A study on internal laryngeal nerve-its variation in the course, branching, anastamosis and relation to inferior thyroid artery

Sailaja K.


Background: Recurrent laryngeal nerves sometimes may not follow the classically describe course. It does not always lie in the tracheo-oesophageal groove. The relations of the nerve to inferior thyroid artery may vary. Therefore, the present study was undertaken to study the variation in the relations and branches of recurrent laryngeal nerve.

Methods: The present study was undertaken in postmortem specimen from Forensic department and cadavers in the dissection hall after the ethical clearance. The specimens were collected enbloc including tongue, oesophagus and trachea. Also, the specimens were used for modified Sihler’s technique. Specimen was dissected and recurrent laryngeal nerve was identified. Its relation and branches were noted. The data regarding the number of branches, level of branching, anastomoses were expressed as percentages.

Results: The nerve was seen passing posterior to the cricothyroid joint to enter the larynx. In 56% of specimens, artery was anterior to the nerve on both sides, nerve was anterior to the artery on both sides in 19%, nerve and artery was found to be ascending in the same plane side artery lateral and nerve medial in 6%, nerve divides before entry into the larynx on both sides in 68%, nerve does not divide in 75%,  Division of the nerve was observed about 4cm below the joint in 6% of specimen, 3cms below the joint in 19% of specimens, 2cm below the in 19% of specimens and 1cm below the joint in 38% of specimens.

Conclusions: It was found that, the nerve was lying posterior to the artery more commonly. There no significant difference between right and left sides. The division of the nerve into anterior and posterior branches before entering the larynx was observed. In half of the specimens, nerve divided before entry into the larynx.


Anastamosis, Branches, Cricothyroid, Recurrent laryngeal nerve, Relations

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