External laryngeal nerve
Encyclopedia
The external laryngeal nerve is the smaller, external branch (ramus externus) of the superior laryngeal nerve
. It descends on the larynx
, beneath the sternothyroid muscle
, to supply the cricothyroid muscle
.
It functions to tense the vocal cords by activating the cricothyroid muscle, increasing pitch.
It gives branches to the pharyngeal plexus
and the superior portion of the inferior pharyngeal constrictor, and communicates with the superior cardiac nerve
behind the common carotid artery
.
or cricothyrotomy
, as it lies immediately deep to the superior thyroid artery
. The ability to produce pitched sounds is then impaired conferring 'hoarseness' on the patient, (usually mono-toned voice).
Not to be confused with damage to the recurrent laryngeal nerve
.
Superior laryngeal nerve
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the ganglion nodosum and in its course receives a branch from the superior cervical ganglion of the sympathetic....
. It descends on the larynx
Larynx
The larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...
, beneath the sternothyroid muscle
Sternothyroid muscle
The Sternothyreoideus is shorter and wider than the Sternohyoideus, beneath which it is situated.It arises from the posterior surface of the manubrium sterni, below the origin of the Sternohyoideus, and from the edge of the cartilage of the first rib, and sometimes that of the second rib, it is...
, to supply the cricothyroid muscle
Cricothyroid muscle
The cricothyroid muscle is the only tensor muscle of the larynx, aiding with phonation. It attaches to the anterolateral aspect of the cricoid and the inferior cornu and lower lamina of the thyroid cartilage, and its action tilts the thyroid forward to help tense the vocal cords...
.
It functions to tense the vocal cords by activating the cricothyroid muscle, increasing pitch.
It gives branches to the pharyngeal plexus
Pharyngeal plexus
Pharyngeal plexus can refer to:* Pharyngeal plexus of vagus nerve* Pharyngeal plexus...
and the superior portion of the inferior pharyngeal constrictor, and communicates with the superior cardiac nerve
Superior cardiac nerve
The superior cardiac nerve arises by two or more branches from the superior cervical ganglion, and occasionally receives a filament from the trunk between the first and second cervical ganglia....
behind the common carotid artery
Common carotid artery
In human anatomy, the common carotid artery is an artery that supplies the head and neck with oxygenated blood; it divides in the neck to form the external and internal carotid arteries. - Structure :...
.
Clinical significance
The external branch is susceptible to damage during thyroidectomyThyroidectomy
A thyroidectomy is an operation that involves the surgical removal of all or part of the thyroid gland. Surgeons often perform a thyroidectomy when a patient has thyroid cancer or some other condition of the thyroid gland...
or cricothyrotomy
Cricothyrotomy
A cricothyrotomy is an incision made through the skin and cricothyroid membrane to establish a patent airway during certain life-threatening situations, such as airway obstruction by a foreign body, angioedema, or massive...
, as it lies immediately deep to the superior thyroid artery
Superior thyroid artery
The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland.-Relations:...
. The ability to produce pitched sounds is then impaired conferring 'hoarseness' on the patient, (usually mono-toned voice).
Not to be confused with damage to the recurrent laryngeal nerve
Recurrent laryngeal nerve
The recurrent laryngeal nerve is a branch of the vagus nerve that supplies motor function and sensation to the larynx . It travels within the endoneurium...
.