Lesson 5.1: Masticatory and lingual muscles

Which branch of the three branches of the trigeminal nerve (V par) is the only one presenting motor fibers?

Mandibular nerve (V3)

What are the groups of muscles?

Masticatory

• Masseter

• Temporais

• Medial pterygoid

• Lateral pterygoid

Suprahyoid

• Mylohyoid

• Geniohyoid

• Anterior belly of digastric

What are the motor branches of the Mandibular nerve (V3)?

• Medial pterygoid muscle nerve

• Deep temporal nerves

• Masseteric nerve

• Lateral pterygoid muscle nerve

• Mylohyoid nerve

Medial pterygoid muscle nerve

• Supplies the medial pterygoid muscle from its deep side.

• Also innervates the tensor veli palatini and tensor tympani muscles

Deep temporal nerves

Branches of the anterior trunck, innervates the temporalis muscle.

Masseteric nerve

It is a branch of the anterior trunck, supplies motor innervation to the

masseteric muscle from its medial side, and sensory innervation to the TMJ

Lateral pterygoid muscle nerve

• Supplies motor innervation to the lateral pterygoid muscle.

• It may be an independient nerve, or a buccal nerve’s lateral branch

Mylohyoid nerve

• It is a branch of the inferior alveolar nerve (posterior trunck).

• It divides just above the mandibular foramen, and runs forwards below the mylohyoid line.

• Innervates the mylohyoid muscle and the anterior belly of the digastric

Masseter: Shape

Short, thick and rectangular

Masseter: Path

From zygomatic arch to the lateral side of the angle and ramus of the mandible

Masseter: Function

Elevates the mandible

Masseter: innervation

V3 - mandibular branch of trigeminal nerve

Masseter: Insertion of Superficial portion

The anterior part of the lower edge of the zygomatic arch

→

Inferior area of the lateral side of the ramus and the angle of the mandible

Masseter: Insertion of Deep portion

Posterior part of the lower edge and medial side of the zygomatic arch

→

Lateral side of the coronoid process and the ramus, superior to the superficial portion

Temporalis: Shape

Wide, flat and triangular

Temporalis: Path

From the temporal fossa to the coronoid process of the mandible

Temporalis: Function

Elevates and retracts the mandible

Temporalis: Innervation

V3 - mandibular branch of trigeminal nerve

Temporalis: Insertion

Temporal fossa, inferior temporal line, infratemporal crest and upper half of the deep temporal fascia

→

Lateral and medial sides of the coronoid process, and the temporal crest

Lateral pterygoid: Shape

Short, thick and flattened

Lateral pterygoid: Path

From the pterygoid process of the sphenoid to the neck of the mandible

Lateral pterygoid: Function

Moves forwards, downward and laterally the mandible

Lateral pterygoid: Innervation

V3 - mandibular branch of trigeminal nerve

Lateral pterygoid: Insertion of upper head

Lower portion of the lateral side of the greater wing of the sphenoid, infratemporal crest and upper third of the lateral side of the lateral plate of pterygoid process

→

Anterior edge of the TMJ disc and anteromedial fossa of the neck of the mandible

Lateral pterygoid: Insertion of lower head

Inferior portion of the lateral side of the lateral plate of pterygoid process, and lateral side of the pyramidal process of the palatine bone

→

Anterior edge of the TMJ disc and anteromedial fossa of the neck of the mandible

Medial pterygoid: Shape

Thick and rhomboid

Medial pterygoid: Path

From the pterygoid process of the sphenoid to the medial side of the

angle of the mandible

Medial pterygoid: Function

Elevates and moves forwards and laterally the mandible

Medial pterygoid: Innervation

V3 - mandibular branch of trigeminal nerve

Medial pterygoid: Insertion of superficial head

Posterior side of the maxillary tuberosity

→

Medial side of the angle and the lower portion of the ramus of the mandible

Medial pterygoid: Insertion of deep head

Pterygoid fossa, medial side of the lateral plate and lateral side of the medial plate of pterygoid process

→

Medial side of the angle and the lower portion of the ramus of the mandible

Geniohyoid: Shape

Short and thick

Geniohyoid: Path

From the mandibular symphysis to the hyoid bone

Geniohyoid: Function

It elevates the floor of the mouth. It elevates the hyoid bone, or descends the jaw

Geniohyoid: Innervation

First spinal nerve (C1) via hypoglossal nerve (XII)

Only exception that is not innervated by mandibular branch of te trigeminal nerve

Geniohyoid: Insertion

Inferior mental spines

→

Anterior side of the body of the hyoid bone

Mylohyoid: Shape

Wide and flattened

Mylohyoid: Path

From the lingual side of the mandible to the hyoid bone and the

median raphe

Mylohyoid: Function

It elevates the floor of the mouth.

It elevates the hyoid bone, or descends the jaw

Mylohyoid: Innervation

V3 - mandibular branch of trigeminal nerve

Mylohyoid: Insertion

Along the mylohyoid line of the mandible

Anterior side of the body of the hyoid bone and median raphe

Anterior belly of the digastric: Shape

Elongated and cylindrical

Anterior belly of the digastric: Path

From the mandibular symphysis to the mastoid region

Anterior belly of the digastric: Function

It elevates the hyoid bone, or descends the jaw

Anterior belly of the digastric: Innervation

V3 - mandibular branch of trigeminal nerve

Anterior belly of the digastric: Insertions

Digastric fossa, in the lower border of the mandible

Mastoid notch of the temporal bone (posterior belly)

What are fascias?

• They are aponeurosis that wrap the different muscles

• They are formed by layers of dense non-oriented connective tissue

• In the masticatory muscles there are three: temporal, masseteric and interpterygoid fascias

Temporal facia

• Covers from the superior temporal line to the zygomatic arch

• At the inferior part has two layers, including adipose tissue

• Is separated from the muscle by a layer of adipose tissue, which increases from top to bottom

Masseteric fascia

• Covers from the zygomatic arch to the posterior and inferior borders of the mandible, and the anterior edge of the coronoid process

• It is thinner, and unfolds to wrap the anterior portion of the parotid gland and the parotid duct

• It is separated from the muscle by a layer of adipose tissue, which increases from top to bottom

Interpterygoid fascia

Located between the medial and lateral pterygoid muscles

• In the posterior side is thicker and more resistant, forming the sphenomandibular Ligament

Which nerve controls the infrahyoid and lingual muscles?

• The hypoglossal nerve (CN12) is a motor nerve

• Control the infrahyoid and lingual muscles (except the palatoglossus muscle)

Which are the Intrinsic and extrinsic lingual muscles?

Intrinsic muscles

• Longitudinal

• Vertical

• Transverse

Extrinsic muscles

• Genioglossus

• Hyoglossus

• Styloglossus

• Palatoglossus (*)

• Amigdaloglossus

• Glossopharyngeal portion of the superior constrictor of pharynx

Longitudinal: Path and function

• From hyoid minor horns, epiglottis, all dorsal side of tongue

• Depresses and shortens the tongue

Vertical: Path and functions

• hyoid minor horns to tip of tongue

• Depresses and retracts the tongue

Transverse

• lingual septum to lateral border of tongue

• Elongates and narrows tongue

Genioglossus: Shape

Flattened and triangular

Genioglossus: Path

From the superior mental spines, to the dorsum and the tip of the tongue,

and the superior border of the hyoid bone

Genioglossus: Function

Retracts the tongue

Genioglossus: Innervation

Hypoglossal nerve (CN12)

Hyoglossus: Shape

Flattened and rhomboidal

Hyoglossus: Path

From the body and the major horns of the hyoid bone, to the lingual septum

Hyoglossus: Function

Retracts the tongue to the floor of the mouth

Hyoglossus: Innervation

Hypoglossal nerve (CN12)

Styloglossus: Shape

Thin and elongated

Styloglossus: Path

From the styloid process of the temporal bone, to the tip of the tongue

Styloglossus: Function

Enlarges and retracts the tongue to the palate

Styloglossus: Innervation

Hypoglossal nerve (CN12)

Palatoglossus: Shape

Thin and flattened

Palatoglossus: Path

From the soft palate to the tip of the tongue

Palatoglossus: Insertion

From the soft palate to the tip of the tongue

Palatoglossus: Innervation

Vagus nerve (CN10)

Amygdaloglossus: Shape

Very thin and elongated

Amygdaloglossus: Path

From the capsule of the palatine tonsil, to the lingual septum

Amygdaloglossus: Function

Raises the base of the tongue

Amygdaloglossus: Innervation

Hypoglossal nerve (CN12)

Glossopharyngeal portion of the superior constrictor of pharynx: Shape

Elongated and flattened

Glossopharyngeal portion of the superior constrictor of pharynx: Path

From posterior portion of the mylohyoid line to the lateral border of the tongue

Glossopharyngeal portion of the superior constrictor of pharynx: Function

Retracts the tongue

Glossopharyngeal portion of the superior constrictor of pharynx: Innervation

Hypoglossal nerve (CN12)