Functions & Innervations of Facial & Swallowing Muscles

What are the the perioral muscles we need to know for dysphagia?

1. Levator labii superioris 2. Depressor labii inferioris 3. Zygomaticus minor 4. Zygomaticus major 5. Depressor anguli oris. 6. Levator anguli oris 7. Risorius 8. Orbicularis oris 9. Buccinator 10. Mentalis

What is the function of the risorius?

Draws corners or angle of mouth outward

What is the function of the levator labii superioris?

Elevation (pulls up) of the upper lip

What is the function of the zygomaticus minor?

Draws upper lip upward and outward

What is the function of the zygomaticus major?

Draws lower lip down and draws the corner of mouth upward and laterally (backward) to smile

What is the function of the depressor anguli oris?

Draws lower lip down and draws angle of mouth down (depresses) & inward

What is the function of the orbicularis oris?

Closes, opens, protrudes, inverts, & twists lips. It allows mouth to close and puckering of the lips.

What is the function of the depressor labii inferioris?

Helps depress and evert (pout) the lower lip

What is the function of the mentalis?

Elevates and protrudes lower lip (pushes it up) and raises chin

What is the function of the buccinator?

Maintains tightness of the cheeks (flattens them) and helps keep a bolus central (holds food in contact with teeth) and retracts angle of mouth

What is the function of the levator labii superior Alaeque?

Raises angle of the mouth

What is the innervation of the facial muscles?

The Facial Nerve (CN VII)

What are the four muscles of mastication?

1. Masseter 2. Temporalis 3. Medial pterygoid 4. Lateral pterygoid

What is the function of the temporal muscle?

Closes jaw & elevates mandible (to bite) and retracts mandible

What is the function of the masseter?

Closes jaw and elevates mandible and provides some protraction of the mandible

What is the function of the medial pterygoid?

Elevates and protrudes mandible (closes mouth), and allows side-to side movement when masticating (contralateral excursion)

What is the function of the lateral pterygoid?

Bilateral contraction of the muscle depresses and protrudes the mandible (opens the mouth)
Unilateral contraction of the muscle moves mandible to the opposite side (biting motion; AKA contralateral excursion)

What is the innervation of the muscles of mastication?

The Trigeminal Nerve (CN V)

What are the intrinsic muscles of the tongue?

1. Superior longitudinal
2. Inferior longitudinal
3. Transverse
4. Vertical

What is the function of the superior longitudinal muscle?

It shortens & widens the tongue & curls the apex and lateral sides of the tongue upwards

What is the function of the inferior longitudinal muscle?

It shortens & widens the tongue & curls the apex of the tongue downward

What is the function of the vertical muscle of the tongue?

Flattens and broadens the tongue

What is the function of the transverse muscle of the tongue?

Narrows and elongates the tongue

What is the innervation of the intrinsic muscles of the tongue?

The Hypoglossal Nerve (CN XII)

What are the extrinsic muscles of the tongue?

1. Genioglossus
2. Hyoglossus
3. Styloglossus
4. Palatoglossus

What is the function of the genioglossus?

Protrusion (sticking it out) and depression of the tongue and laryngeal elevation

What is the function of the hyoglossus?

Retraction and depression of the tongue and laryngeal elevation

What is the function of the styloglossus?

Retraction and elevation of the tongue

What is the function of the palatoglossus?

Elevation of the posterior tongue (back of it)

What is the innervation of the extrinsic muscles of the tongue?

The Hypoglossal Nerve (CN XII) except the palatoglossus which is innervated by the Vagus Nerve (CN X)

What is the only extrinsic muscle of the tongue that isn't bilaterally innervated?

The genioglossus (stroke on right side of the brain could cause motor deficits of the left genioglossus resulting in deviation of the tongue to the left when it is protruded)

What are the muscles of the palate?

1. Levator veli palatini
2. Tensor veli palatini 3. Palatoglossus 4. Palatopharyngeous
5. Uvulae

What is the function of the levator veli palatini muscle?

Elevation of the soft palate during swallowing

What is the function of the tensor veli palatini muscle?

Stretches/tense the soft palate and dilates the Eustachian tube

What is the function of the palatopharyngeus muscle?

Shut the nasopharynx during the second stage of swallowing and shortens the pharynx (pulls pharynx & larynx upward)

What is the function of the musculus uvulae?

Shortens and raises the uvula

What is the innervation of the muscles of the palate?

The Vagus nerve (CN X), except for the tensor veli palatini muscle that is innervated by the Trigeminal (CN V)

What are the extrinsic laryngeal muscles?

suprahyoid and infrahyoid muscles

What are the suprahyoid muscles?

1. Digastric
2. Mylohyoid
3. Stylohyoid
4. Geniohyoid

What is the function of the digastric muscle?

Elevation of the hyoid bone and depression of the mandible if the hyoid is fixed

What is the function of the geniohyoid muscle?

Elevates & draws hyoid bone anteriorly (brings it forward & upward) and depresses the mandible (shortens mouth floor) - important for deglutition

What is the function of the stylohyoid muscle?

Elevates and draws hyoid bone posteriorly (upward & backward) resulting in elevation of the tongue base and elongation of the mouth floor

What is the function of the mylohyoid muscle?

Elevates hyoid bone & oral cavity (floor of mouth), & depresses the mandible

What is the innervation of the suprahyoid muscles?

The Trigeminal Nerve (CN V) for the mylohyoid and anterior belly of digastric, the Hypoglossal Nerve (CN XII) for the geniohyoid, and the Facial Nerve (CN VII) for the stylohyoid and posterior belly of digastric

What are the infrahyoid muscles?

1. Thyrohyoid
2. Omohyoid
3. Sternohyoid
4. Sternothyroid

What is the function of the thyrohyoid muscle?

Depression of the hyoid and elevation of the thyroid

What is the innervation of the thyrohyoid muscle?

Hypoglossal nerve (CN XII)

What are the pharyngeal muscles?

1. Superior pharyngeal constrictor
2. Middle pharyngeal constrictor
3. Inferior pharyngeal constrictor
4. Stylopharyngeus
5. Salpingopharyngeus
6. Palatopharyngeus

What are the long pharyngeal muscles?

Stylopharyngeus, salpingopharyngeus, palatopharyngeus

What is the function of the pharyngeal constrictor muscles?

To constrict the pharynx and move the bolus down the esophagus

What is the function of the stylopharyngeus muscle?

Elevates the pharynx and larynx, dilates pharynx

What is the function of the salpingopharyngeus muscle?

Draws the lateral walls of the pharynx up (elevates it) and opens ET

What is the function of the cricopharyngeus muscle?

Acts as a sphincter between the pharynx and the esophagus (prevents reflux of food); the functional UES (attached to larynx)

What is the innervation of the pharyngeal constrictor muscles?

The vagus nerve (CN X)

What is the innervation of the salpingopharyngeus, stylopharyngeus, and cricopharyngeus?

The Glossopharyngeal Nerve (CN IX) for the stylopharyngeus and the Vagus Nerve (CN X) for the salpingopharyngeus and cricopharyngeus

What are the intrinsic laryngeal muscles & their function (briefly)?

Cricothyroid - VF adduction
Thyroarytenoid - shortens VFs, reduced tension & lowers pitch
Lateral Cricoarytenoid - VF adduction
Interarytenoid - VF adduction
Posterior Cricoarytenoid - VF Abduction
Aryepiglottic - Adducts arytenoids & acts as a sphincter

What is the CN innervation of the intrinsic laryngeal muscles?

The vagus nerve (CN X)

What is the function of the upper & lower esophageal sphincter muscles?

To keep gastric contents from coming back up and refluxing