Superior laryngeal nerve

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Superior laryngeal nerve

The superior laryngeal nerve is a branch of the vagus nerve (cranial nerve X) that innervates the larynx. It plays a crucial role in the sensory and motor functions of the larynx, which is essential for speech and swallowing.

Anatomy

The superior laryngeal nerve arises from the inferior ganglion of the vagus nerve. It descends alongside the pharynx and divides into two branches: the internal laryngeal nerve and the external laryngeal nerve.

Internal Laryngeal Nerve

The internal laryngeal nerve pierces the thyrohyoid membrane to provide sensory innervation to the mucosa of the larynx above the vocal cords.

External Laryngeal Nerve

The external laryngeal nerve descends to innervate the cricothyroid muscle, which is involved in the tension and lengthening of the vocal cords.

Function

The superior laryngeal nerve is responsible for:

• Sensory innervation of the laryngeal mucosa above the vocal cords.
• Motor innervation to the cricothyroid muscle, which adjusts the tension of the vocal cords during speech.

Clinical Significance

Damage to the superior laryngeal nerve can result in a loss of sensation above the vocal cords and a weakened ability to tense the vocal cords, leading to a hoarse voice or difficulty in producing high-pitched sounds. This can occur due to surgical procedures, trauma, or tumors affecting the nerve.

Related Structures

• Recurrent laryngeal nerve
• Vagus nerve
• Larynx
• Cricothyroid muscle
• Thyrohyoid membrane

See Also

• Laryngeal nerves
• Vocal cords
• Speech pathology