During a thyroid operation, a nerve coursing along with the superior thyroid artery is injured. What can be the possible consequence(s):
Ans: D (Paralysis...) External laryngeal nerve accompanies the superior thyroid arteryLARYNGEAL NERVES BDC4th/VoUil 135# The superior laryngeal nerve arises from the inferior ganglion of the vagus, runs downwards and forwards on the superior constrictor, deep to the internal carotid artery, and reaches the middle constrictor where itdivides into the external & interna! laryngeal nerve.Rxternal laryngeal nerve is thin. It accompanies the superior thyroid artery, pierces the inferior constrictor and ends by supplying the cricothyroid muscle. It also gives branches to the inferior constrictor and to the pharyngeal plexus.The internal laryngeal nerve is thick. It passes downwards and forwards, pierces the thyrohyoid membrane (above the superior laryngeal vessels) and enters the larynx. It supplies the mucous membrane of the larynx upto the level of the vocal foldsThe right recurrent laryngeal nerve arises from the vagus in front of the right subclavian artery, winds backwards below the artery, and they runs upwards and medially behind the subclavian and common carotid arteries to reach the tracheo-oesophageal groove, [n the upper part of the groove, it is related to the inferior thyroid artery. It may be superficial or deep to the artery.Left Recurrent Laryngeal Nerve - It arises from the vagus in the mediastinum at the level of arch of aorta, loops around it & then ascends into the neck in the tracheo-oesophageal groove. Thus, Lt RLN has a much longer coursef which makes it more prone to paralysis as compared to the right one.NERVE SUPPLY OF LARYNX MotorAll the muscles which move the vocal cords are supplied by Recurrent Laryngeal nerveS except the cricothyroid muscle. The latter receive its innervation from External Larymgeal nerved - a branch of superior Laryngeal nerveSensoryAbove vocal cords - Internal Laryngeal nerve a branch of Superior Laryngeal nerveBelow vocal cords - Recurrent Laryngeal nerveFig: Thyroid arteries & their relation with nerves
Loss of sensation above vocal cord
Loss of sensation below vocal cord
Paralysis of lateral cricoarytenoid muscle
Paralysis of cricothyroid muscle
Thyroid Gland