Cranial Nerves - CN X Vagus

What is the cricothyroid muscle supplied by?

External laryngeal nerve (branch of the vagal). Pierces the cricothyroid membrane to reach muscles deep to it.

What innervation does the internal branchof the superior laryngeal nerve provide?

Sensory branches to mucus membrane base of the tongue epiglottis and larynx as far as the vocal folds

Which branch of the vagus arises at the thoracic inlet?

Recurrent laryngeal nerve

Which modalities apply to CN X? (5)

1) GVE - supply smooth muscle and glands of digestive tract 2) SVE - muscles derived from fourth and sixth pharyngeal arches 3) GSA - cutaneous sensation of the ear and external acoustic meatus 4) GVA - supplies a number of mucus membranes associated with viscera 5) SVA - supply base of the tongue and larynx In addition to serving structures in the head and neck, the vagus nerve also enters the thorax to serve the heart and lungs and continues to the abdomen to supply most of the abdominal viscera.

What is the general function of CN X?

1) Motor to palate, pharynx and larynx 2) Sensory to pharynx and larynx Taste, swallowing, cough reflex, speaking

The vagus nerve supplies which pharyngeal arches?

Fourth and sixth. Vagus nerve is the nerve of the fourth pharyngeal arch and recurrent laryngeal branch is nerve of the sixth laryngeal arch. So supplies muscles derived from thos pharyngeal arches.

The cranial root of CN XI joins the vagus nerve proximal to which ganglion?

Inferior ganglion (sensory ganglion)

The recurrent laryngeal nerve ascends back towards the neck and enters the larynx as what?

Inferior laryngeal nerve

Which muscles derived from the sixth pharyngeal arch does the vagus nerve innervate?

Intrinsic muscles of the larynx

What does the inferior laryngeal nerve innervate?

Intrinsic muscles of the larynx EXCEPT the cricothyroid muscle

Through which foramen does CN X exit the skull?

Jugular foramen

What type of nerve is CN X?

Mixed

What innervation does the external branch of the superior laryngeal nerve provide?

Motor to cricothyroid muscle and inferior pharyngeal constrictor muscles

What are the peripheral distributions of CN X?

Muscles of palate, pharynx, larynx, sensory to tongue, larynx

Where do the fibres of the pharyngeal branches of the vagus nerve going into the pharyngeal plexus originate?

Nucleus ambiguus and innervate muscles of the soft palate, pharynx, larynx and upper oesophagus

What is the central connection of CN X?

Nucleus in medulla

The vagus nerve innervates one extrinsic muscle of the tongue, which is it?

Palatoglossus muscle

Which muscles derived from the fourth pharyngeal arch does the vagus nerve innervate?

Pharyngeal constrictors and cricothyroid muscles

The pharyngeal branches of the vagus nerve provide input into which plexus?

Pharyngeal plexus

The vagal fibres supply sensory information to which other structure of the neck?

Pharynx

A small sensory branch of the vagus supply the dura of what?

Posterior cranial fossa

The vagal fibres suppy sensory innervation a small branch called the auricular branch which innervates what?

Skin around the auricle and part of the external acoustic meatus.

Which other nerve also makes a contribution to the motor function of the pharynx from its cranial root?

Spinal acessory nerve XI

The vagus nerve innervates all the muscles of the soft palate except for which one?

Tensor veli palatini (innervated by mandibular division of trigeminal)

True or false: recurrent laryngeal branches supply the larynx below the vestibular fold

True

True or false: vagal fibres provide sensory innervation to the larynx

True (above vestibular fold)