Recurrent laryngeal nerve
Division or branch · CN X Mixed
The vagal branch that turns back up into the neck: the right loops under the right subclavian artery and the left under the aortic arch behind the ligamentum arteriosum, giving the left a long intrathoracic course through the aortopulmonary window. Both ascend in the tracheo-oesophageal groove, cross the branches of the inferior thyroid artery behind the thyroid lobe and enter the larynx behind the cricothyroid joint. Motor to every intrinsic laryngeal muscle except cricothyroid; sensory below the vocal folds.
Traced from the start
Detail
- Motor
- Posterior cricoarytenoid (the only abductor), lateral cricoarytenoid, thyroarytenoid and vocalis, transverse and oblique arytenoids; not cricothyroid
- Sensory
- Laryngeal mucosa below the vocal folds and the upper trachea
- Course
- Right: under the right subclavian artery. Left: under the aortic arch behind the ligamentum arteriosum. Then the tracheo-oesophageal groove, intimately related to the inferior thyroid artery and the thyroid lower pole
- Non-recurrent variant
- On the right, with an aberrant retro-oesophageal subclavian artery, the nerve runs directly medially from the vagus and is easily cut
When it goes wrong
Thyroidectomy or parathyroidectomy injuring one recurrent laryngeal nerve near the inferior thyroid artery
Hoarse breathy voice and a weak cough with the cord fixed in the paramedian position; bilateral injury leaves both cords near the midline with stridor and airway obstruction on extubation, needing reintubation or tracheostomy
Left recurrent laryngeal nerve compressed in the chest by apical lung cancer, mediastinal lymph nodes, an aortic arch aneurysm or a huge left atrium in mitral stenosis (Ortner syndrome)
Progressive painless hoarseness with a paralysed left cord; a right-sided palsy is more often from a thyroid or neck cause
Hoarseness lasting more than three weeks in a smoker, or any unexplained vocal cord palsy
Laryngoscopy is mandatory and CT from skull base to mediastinum is needed to find the lesion along the nerve's course
Practise this structure
1 question in the bank tagged Vagus Nerve.