Info: Recurrent laryngeal nerve
The recurrent (inferior) laryngeal nerve is a branch of the vagus nerve (tenth cranial nerve) that supplies motor function and sensation to the larynx (voice box). It travels within the endoneurium. It is the nerve of the 6th Branchial Arch.
Path:
It is referred to as "recurrent" because the branches of the nerve innervate the laryngeal muscles in the neck through a rather circuitous route: it descends into the thorax before rising up between the trachea and esophagus to reach the neck.
The left laryngeal nerve, which is longer, branches from the vagus nerve to loop under the arch of the aorta, posterior to the ligamentum arteriosum before ascending. On the other hand, the right branch loops around the right subclavian artery. As the recurrent nerve hooks around the subclavian artery or aorta, it gives off several cardiac filaments to the deep part of the cardiac plexus. As it ascends in the neck it gives off branches, more numerous on the left than on the right side, to the mucous membrane and muscular coat of the esophagus; branches to the mucous membrane and muscular fibers of the trachea; and some pharyngeal filaments to the superior pharyngeal constrictor muscle.
The nerve splits into anterior and posterior rami before supplying muscles in the voice box – it supplies all laryngeal muscles except for the cricothyroid, which is innervated by the external branch of the superior laryngeal nerve.
The recurrent laryngeal nerve enters the pharynx, along with the inferior laryngeal artery and inferior laryngeal vein, below the inferior constrictor muscle to innervate the Intrinsic Muscles of the larynx responsible for controlling the movements of the vocal folds.
Clinical significance:
The nerve is best known for its importance in thyroid surgery, as it runs immediately posterior to this gland. If it is damaged during surgery, the patient will have hoarseness. Nerve damage can be assessed by laryngoscopy, during which a stroboscopic light confirms the absence of movement in the affected side of the vocal cords.
Similar problems may also be due to invasion of the nerve by a tumor or after trauma to the neck. A common scenario is paralysis of the left vocal cord due to malignant tumour in the mediastinum affecting the left recurrent laryngeal nerve. The left cord returns to midline where it stays.
If the damage is unilateral, the patient may present with voice changes including hoarseness.
Bilateral nerve damage can result in breathing difficulties and aphonia, the inability to speak.
The right recurrent laryngeal nerve is more susceptible to damage during thyroid surgery due to its relatively medial location.
The recurrent (inferior) laryngeal nerve is a branch of the vagus nerve (tenth cranial nerve) that supplies motor function and sensation to the larynx (voice box). It travels within the endoneurium. It is the nerve of the 6th Branchial Arch.
Path:
It is referred to as "recurrent" because the branches of the nerve innervate the laryngeal muscles in the neck through a rather circuitous route: it descends into the thorax before rising up between the trachea and esophagus to reach the neck.
The left laryngeal nerve, which is longer, branches from the vagus nerve to loop under the arch of the aorta, posterior to the ligamentum arteriosum before ascending. On the other hand, the right branch loops around the right subclavian artery. As the recurrent nerve hooks around the subclavian artery or aorta, it gives off several cardiac filaments to the deep part of the cardiac plexus. As it ascends in the neck it gives off branches, more numerous on the left than on the right side, to the mucous membrane and muscular coat of the esophagus; branches to the mucous membrane and muscular fibers of the trachea; and some pharyngeal filaments to the superior pharyngeal constrictor muscle.
The nerve splits into anterior and posterior rami before supplying muscles in the voice box – it supplies all laryngeal muscles except for the cricothyroid, which is innervated by the external branch of the superior laryngeal nerve.
The recurrent laryngeal nerve enters the pharynx, along with the inferior laryngeal artery and inferior laryngeal vein, below the inferior constrictor muscle to innervate the Intrinsic Muscles of the larynx responsible for controlling the movements of the vocal folds.
Clinical significance:
The nerve is best known for its importance in thyroid surgery, as it runs immediately posterior to this gland. If it is damaged during surgery, the patient will have hoarseness. Nerve damage can be assessed by laryngoscopy, during which a stroboscopic light confirms the absence of movement in the affected side of the vocal cords.
Similar problems may also be due to invasion of the nerve by a tumor or after trauma to the neck. A common scenario is paralysis of the left vocal cord due to malignant tumour in the mediastinum affecting the left recurrent laryngeal nerve. The left cord returns to midline where it stays.
If the damage is unilateral, the patient may present with voice changes including hoarseness.
Bilateral nerve damage can result in breathing difficulties and aphonia, the inability to speak.
The right recurrent laryngeal nerve is more susceptible to damage during thyroid surgery due to its relatively medial location.
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