Pharyngeal-Oral Function

A. (Dentition) 1. *Permanent teeth*
a. How many teeth are in the alveolar processes of the maxilla and the mandible?

a. A total of 32 teeth are in the alveolar processes of the maxilla and the mandible

b. One *quadrant* (one-fourth of the entire dental arch; half of upper or lower dental arch) contains:

· *1 central incisor
· 1 lateral incisor
· 1 canine/cuspid
· 2 premolars/bicuspids
· 3 molars*

[Note: Cusp is "the point of the crown of a tooth"; a cuspid/canine has one point;

a bicuspid has two cusps, a buccal cusp and a lingual cusp; a molar has four cusps, two are buccal cusps and two are lingual cusps.]

How many deciduous teeth (baby teeth) are there?

a. 20
In one quadrant:
· 1 central incisor
· 1 lateral incisor
· 1 canine/cuspid
· 2 molars

What are the *surfaces* of the teeth?

lingual, buccal, labial, mesial, distal, occlusal

*Lingual*

toward the tongue

*Buccal*

toward the cheek (This is the tooth surface that faces the outside of your mouth. It is the tooth surface that is closest or next to your cheek.)

*Labial*

toward the lips

*Mesial*

(toward the midline, that is, between the central incisors

*Occlusal*

the occlusal surfaces of the maxillary molars contact the occlusal surfaces of the mandibular molars when the dental arches are occluded. (It's the surface of the back (molar and premolar) teeth that is used for biting or chewing.)

What is *dental occlusion?*

This refers to the contact the teeth of the upper dental arch make with those of the lower arch. The teeth of the maxillary (upper) arch slightly overlap those of the mandibular (lower) arch.

What is normal occlusion?

The first mandibular molar is 1⁄2 tooth ahead of the first maxillary molar. (With more detail: the mesiobuccal cusp of the first maxillary molar makes contact with the mesiobuccal groove of the first mandibular molar.)

What is class I malocclusion?

normal occlusion; abnormal positioning of the anterior teeth. A class 1 malocclusion means that the molar position, or bite, is normal, but there are other teeth that are misaligned in some way. These anomalies can include: Overlapping or overcrowded teeth. Rotated teeth.

What is class II malocclussion?

first mandibular molar is behind its normal position. (This can be associated with a retruded mandible.) OVERBITE, NO JAW, think leafy

What is class III malocclusion?

first mandibular molar is in front of its normal position. (This can be associated with a protruded mandible.) UNDERBITE, think crimson chin

B. (Sinuses) What are the *paranasal sinuses?*

The paranasal sinuses are air-filled spaces in certain bones of skull that open into the nasal cavities are lined with mucous membrane that is continuous with the nasal cavities.

What function do *paranasal sinuses* have in speech?

They have minimal function in speech.

What is the location of the *frontal sinuses?*

*Frontal sinuses* are located within two layers of the frontal bone at the superciliary arches (location of eyebrows)

What is the location of the *maxillary sinuses?*

Maxillary sinuses are in the bodies of the maxillae.

What are the two other paranasal sinuses?

Sphenoid sinuses, and Ethmoid sinuses.

C. (Oral cavity) What is the roof of the oral cavity?

*Hard palate* and *velum*
- *median raphe*—ridge down the middle of the hard palate (runs below the median palatine suture)

What is the posterior boundary of the oral cavity?

*Faucial isthmus*, marked by the anterior posterior faucial pillars (palatoglossal folds)

What is the floor of the oral cavity?

the *tongue*

What is the *buccal cavity*?

The*Buccal cavity*is the space between the cheeks (and lips) to the outside and the teeth and alveolar process (gums) to the inside.

(Mandible) What are the biological functions of the mandible?

*Biological*: mastication, that is, chewing.

What are the speech functions of the mandible?

i. The mandible works together with the tongue to *modify resonance*

ii. The mandible influences the position of...

*the tongue and lower lip.*

iii. The extent of mandible movement during speech is...

slight

b. "Inadequate, inappropriate, or sluggish movements may contribute to...

articulatory deficits."

(Mandible and Temporomandibular Joint (TMJ)) What is the *body* of the mandible?

The large horseshoe-shaped portion around the front and sides of the mandible.

What is the *ramus* of the mandible?

The large vertically directed portions at the back of the mandible.

The ramus' coronoid process is in the...

front

The ramus' condyloid process is in the...

back

Where is the "angle" of the mandible located?

located at the junction of the inferior border of the body of the mandible and the posterior border of the ramus.

What is the Temporomandibular joint (TMJ)?

This is the articulation (joint) between the mandible and the temporal bones.

What are the components of the temporomandibular joint (TMJ)?

*mandibular fossa*, *condyloid (condylar) process*, articular meniscus/disc

What is the *mandibular fossa*?

a depression below the base of the posterior end of the zygomatic arch

What is the *condyloid (condylar) process* of the mandible?

the rounded process by which the ramus of the mandible articulates with the temporal bone.

What is the articular meniscus/disc?

donut shaped cartilage between the other two components.

What is the function of the temporomandibular joint (TMJ)?

(a) to raise and lower the mandible, (b) to protrude and retract the mandible, and (c) to move the mandible from side to side

Where is the upper compartment located?

It is located between the disc and the mandibular fossa.

What movement does the upper compartment allow?

Allows *the whole joint to slide forward or backward as the mandible is lowered or elevated.*

Where is the lower compartment located?

It is located between the disc and the mandibular condyle, contact each other.

What movement does the lower compartment allow?

Allows the *condyle to rotate within the center of the "donut."*

What are the *mandibular elevators?*

masseter, temporalis, internal pterygoid muscle

1. What is the origin of the *masseter muscle?*

Origin: [Anterior 2/3 of lower surface of the *zygomatic arch.*

What is the insertion of the *masseter muscle?

Insertion: *Angle of the mandible & lateral surface of ramus*

2. What is the origin of the *temporalis muscle?*

Origin: *Temporal fossa*, the depressed area on the lateral surface of the skull.

What is the insertion of the *temporalis muscle?*

Insertion: Fibers converge to pass medial (under) the zygomatic arch to insert onto the *coronoid process of the mandible.*

3. What is the origin of the *Internal pterygoid muscle (medial pterygoid)?*

Origin: P*terygoid process* (lateral pterygoid plate)

3. What is the insertion of the *Internal pterygoid muscle (medial pterygoid)?*

Insertion: Courses *parallel to the masseter muscle, but* along the inner surface of the ramus; *inserts onto the deep surface of the angle of the mandible.*

What are the *mandibular depressors?*

*External pterygoid (lateral pterygoid) muscle, digastric muscle (anterior belly), mylohyoid muscle, geniohyoid muscle*

1. What is the origin of the *External pterygoid muscle (lateral pterygoid)?*

Origin: Pterygoid process

What is the insertion of the *External pterygoid muscle (lateral pterygoid)?*

Courses horizontally back to insert onto the *neck of the mandibular condyle.*

What are the functions of the *External pterygoid muscle (lateral pterygoid)?*

i. *protrudes mandible*
ii. Alternating contractions of the right & left muscle will *lateralize the mandible from side to side."
iii. Also can assist to *depress* (lower) the mandible

2. *Digastric muscle (anterior belly)*

a. *Anterior belly*—Courses from the *digastric fossa*, on the lower lingual surface of the mandible, posteriorly to the *intermediate tendon* at the hyoid bone.

The posterior belly is connected to...

i. the anterior digastric by the intermediate tendon at the hyoid bone; courses posteriorly to the *mastoid process.*
ii. Fibrous loop loosely anchors the intermediate tendon to the hyoid bone.

What is the function of the *anterior belly* re mandible?

*Depresses mandible* if the hyoid bone is fixed in place.

What are the functions of the anterior & posterior bellies re larynx?

Elevate the hyoid bone and larynx if the mandible is fixed in place.

What is the origin of the *mylohyoid muscle?*

Origin: *Lingual surface of the body of the mandible* [from ridges, called the mylohoid lines].

What is the insertion of the *mylohyoid muscle?*

Insertion: Median raphe [tendinous seam that runs from the center of the mandible to the hyoid bone] and *the body of the hyoid bone.*

What is the function of the *mylohyoid muscle?*

i. *Depresses mandible* if the hyoid bone is fixed in place.
ii. Elevates the hyoid bone & larynx if the mandible is fixed.

What is the origin of the *geniohyoid muscle?*

Origin: Immediately above the mylohyoid ms., *near the center of the posterior surface of the mandible.*

What is the insertion of the *geniohyoid muscle?*

Body of the *hyoid bone.*

What is the function of the *geniohyoid muscle?*

i. *Depresses mandible* (if the hyoid bone is fixed in place).
ii. Elevates the hyoid bone & larynx (if the mandible is fixed).

Innervation: Motor innervation to *most mandibular ms.* -

*CN V (5), trigeminal nerve.*

What elevates the mandible?

*temporalis, masseter, medial pterygoid*

What depresses the mandible?

lateral pterygoid muscle, anterior digastric (anterior belly) muscle, mylohyoid muscle, geniohyoid muscle

What protrudes the entire mandible or one side?

lateral pterygoids

What retracts the mandible?

Temporalis, anterior digastric

What lateralizes the mandible from side to side?

Lateral pterygoid (external pterygoid) muscle

What is a *biological* function of the *tongue?*

a. Sense of taste

What is another *biological* function of the *tongue?*

b. Mastication (move food around in mouth).

What is another *biological* function of the *tongue?*

c. Swallowing (move bolus into pharynx).

What is a *speech* function of the *tongue?*

It *modifies resonance* of the vocal tract

What does modifying resonance of the vocal tract do to it?

i. This changes the shape of vocal tract

The tongue modifying resonance for the vocal tract produces the unique characteristics for...

Vowels and sonorant consonants

What is another *speech* function of the *tongue?*

*valves airflow*

i. *Valves airflow" stops airflow for...

Stops

i. Valve airflow constricts airflow for...

Fricatives

What are the *anatomical divisions* of the tongue? (Fig. (5-8)

a. *Tip/apex*
b. *Blade*
c. *Dorsum*
d. *Root*

*Blade*

The horizontal portion of the tongue; its dorsal surface faces the hard and soft palates

*Dorsum/dorsal surface*

entire upper surface of the tongue's body & root

*Root*

the vertical portion of the tongue at the back; its surface faces the posterior pharyngeal wall

What is the *lingual frenulum/ frenulum?*

Membrane connecting tongue to floor of oral cavity.

What is anklyoglossia?

Frenulum is too short for normal tongue protrusion ("tongue-tied"); uncommon

What is the *longitudinal median sulcus?* (Fig. 4-5)

groove running along the midline of the oral surface of the tongue.

(Deep structures of the tongue) a. What is the Lingual septum/median fibrous septum?

thin vertical plate of connective tissue found in the midline of the oral portion of the tongue.

b. The body of the tongue consists of...

muscle fibers.

What are the *muscles* of the tongue?

Intrinsic and extrinsic muscles

*Intrinsic muscles* connections are largely within...

*the tongue.*

ii. Intrinsic muscle primarily *change shape*of the...

tongue (flatten, elongate, lift
tip, lower tip).

*Extrinsic muscles* connect to a structure...

*outside the tongue

ii. The extrinsic muscles primarily *position tongue* within the...

oral cavity; also protrude and retract

(Muscular hydrostat) The tongue is a *muscular hydrostat:*

It is a muscular structure that *acts like a fluid-filled structure* (e.g., such as a water balloon), which changes shape when a part of the structure is displaced, but which maintains a steady volume.

This structure gives the tongue the ability to perform...

many movements during articulation, chewing, and swallowing: curl, groove, bulge, point, etc.

(Innervation) What is the motor innervation of the tongue?

CN 12/XII (hypoglossal)

(Innervation) General sensation:

a. To anterior 2/3 (oral portion/body): CN 5/V / Trigeminal nerve
b. To posterior 1/3 (pharyngeal portion/root): CN 9/IX / Glossopharyngeal nerve

What are the *intrinsic muscles?*

*Superior longitudinal (paired), Inferior longitudinal (paired), Vertical (paired), Transverse (paired)*

What is the origin of the *superior longitudinal (paired) muscle*?

Origin: *Root of tongue*