Left recurrent laryngeal nerve

Nervus laryngeus recurrens sinister

NervousNervesWhole bodyLeft side

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What it is
Leaves the left vagus as it crosses the aortic arch, hooks under the arch behind the ligamentum arteriosum and climbs back up in the groove between the trachea and oesophagus to enter the larynx behind the thyroid gland.
Function
Motor to all intrinsic laryngeal muscles except the cricothyroid, and sensation below the vocal folds - it opens and closes the vocal cords.
Size
About 1 mm thick, ~15 cm on the left (the right is ~5 cm shorter)
Clinical note
Its detour into the chest lets a lung cancer or enlarged left atrium paralyse the left vocal cord, causing a hoarse voice; it is also the nerve thyroid surgeons must protect.

Part of Left vagus nerve (CN X)

Nearby nervous structures Accessory nerve (CN XI), Brachial plexus, Cardiac plexus, Cervical plexus, Left phrenic nerve, Right phrenic nerve, Right recurrent laryngeal nerve, Right vagus nerve (CN X), Spinal cord, Spinal dura mater (dural sac)