DOI: http://dx.doi.org/10.18203/2320-6012.ijrms20163338

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

Sailaja K.

Abstract


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.


Keywords


Anastamosis, Branches, Cricothyroid, Recurrent laryngeal nerve, Relations

Full Text:

PDF

References


Bacchi G, Pizzolitto S. An anastomatic loop between the recurrent nerves – an anatomical description. Acta Otorhinolaryngol Ital. 1992;12(1):23-32.

Brauckhoff M, Walls G, Brauckhoff K, thanh PN, thomusch O, dralle H. identification of the non-recurrent inferior laryngeal nerve using intraoperative neurostismulation. Langenbecks Arch Surg. 2002;386(7):482-7.

Brok HA, copper MP, stroeve RJ, ongerboer de visser BW, venker-van haagen AJ, schouweenburg PF. Evidence for recurrent laryngeal nerve contribution in motor innervations of the human circopharyngeal muscle. Laryngoscope. 1999;109(5):705-8.

Furstenberg AC. an anatomical and clinical producing paralysis of the larynx. Ann Otol Rhin & laryng 46:39,1937.

Hammond CS, Davenport PW, Hutchison A, Otto RA. Motor innervations of the circopharyngeus muscle by the recurrent laryngeal nerve. J Appl physiol. 1997;83(1):89-94.

Desaki J, kawakita S, yagamata T. occurrence of capiliaries with fenestrae in the intrinsic laryngeal muscles of the guinea pig after unilateral denervation. J Electron microsc (Tokyo). 1997;46(6):491-5.

Dovas A, lucchi ML, bortolami R, grandis A, palladino AR, banelli E, et al. collaterals of recurrent laryngeal nerve fibres innervate the thymus: flurescent in the rat brainstem. Brain res. 1998;809(2):141-8.

Berlin DD, Lahey FH. dissection of the recurrent and superior laryngeal nerves. The relations of the recurrent to the inferior thyroid artery and the relation of the superior to abductor paralysis. Surg., gynec. & obst. 1929;49:102.

Hornung TS, Nicholson IA, nunn GR, hawker RE. Neonatal ductus arteriosus aneurysm causing nerve palsies and airway compression: surgical treatment by decompression without excision. Pediatr cardiol. 1999;20(2):158-60.

Taguchi K. die lage des nervus recurrences nervi vagi zur arteria thyroidea inferior. Arch Anat Physiol Wissen Med. 1889;309-25.

Fowler CH, Hanson WA surgical anatomy of the tyroid gland with special reference to the relations of the recurrent laryngeal nerve. Surg gynec & obst. 1929;49:59.

Reed AF. The relation of the inferior laryngeal nerve to the inferior thyroid artery. Anat Rec. 1943;85:17-23.

Hogg RP, Kuo MJ, Olliff J, Das Gupta AR. Invasion of the recurrent laryngeal nerve by adenoid cystic carcinoma. An unusual cause of true vocal fold paralysis. J Laryngol Otol. 1999;113(3):260-2.

Morrison LF. Bilateral paralysis of abductor muscles of the larynx: report on seven patients treated by the method outlined by Dr. Brient t. king. Arch Otalaryng. 1943;37:54.

Al-salihi AR, Dubbegh AW. Anatomy of the recurrent laryngeal nerve in normal Iraqis. Acta Anat (Basel). 1989;135(3):245-7.

Nagayama I, Okabe Y, Katoh H, Furukawa M. importance of pre-operative recognition of the nonrecurrent laryngeal nerve. J laryngol otol. 1994;108(5):417-9.