A&P of Speech Final

Skeletal Structure

Maxilla (upper jaw and most of the hard palate)

Mandible (lower jaw)

Frontal bone

Zygomatic bone

Sphenoid bone

Temporal bone

Parietal bone

Styloid process

Skeletal Structure of Maxilla

alveolar process

nasal notch

facial surface

body of maxilla

permanent teeth

palatine process of maxilla

horizontal process of palatine bone

Skeletal Structure of Mandible

alveolar process

ramus

• coronoid process

• condylar process

body

teeth

Teeth Types

Incisors: front 2 (on each side)

Canines: 3rd tooth (on each side)

Premolars: 4 & 5th teeth

Molars: back 3 teeth

***ICPM

First teeth are developed around…?

4-6 months

teeth are important for speech

Molars

Developed later compared to many other teeth

• 1st usually at age 6

• 2nd age 12

• 3rd (wisdom teeth) age 18

What forms the Temporomandibular Joints (TMJ)?

The mandible articulating (attaching) with the left and right temporal bones

Each TMJ is a condyloid joint

egg-shaped condylar head fits into an elliptical cavity in the temporal bone

articular surfaces of the condyle and temporal bone are covered with fibrocartilage (prevents wear and tear)

3 Temporomandibular Ligaments

Temporomandibular ligament

Sphenomandibular ligament

Stylomandibular ligament

Temporomandibular ligament

limits downward and backward displacement of the condyle

Sphenomandibular ligament

limits downward and backward displacement of the mandible

Stylomandibular ligament

limits downward and forward displacement of the mandible

Occlusion

relationship btwn maxillary and mandibular teeth when they come together for chewing or when at rest/bones are attached and tightly closed

Movements of the mandible

Lowers and raises

Forward and back

Side to side

pharyngeal-oral apparatus cavities (2)

oral cavity

buccal cavity

Oral Cavity

Bounded by:

• Front and sides: lips, teeth, and alveolar processes of the maxilla and mandible.

• Top: hard palate and velum (soft palate).

• Bottom: floor of the mouth, mostly made up of tongue

• Back: anterior faucial pillars (palatoglossal arches) — the tissue just behind the most posterior molars.

oral vestibule is the front entry to the oral cavity

tongue = most prominent feature

5 primary functional/anatomical subdivisions of Tongue

• Tip: located nearest the front teeth when the tongue is at rest

• Blade: surface region that lies behind the tip and below the alveolar ridge of the maxilla and the anterior hard palate

• Dorsum: lies behind the blade and below the posterior hard palate and velum.

• Root: faces the back of the pharynx and front of the epiglottis.

• Body: central mass underlying the 4 other regions

Buccal Cavity

on the sides of the oral cavity, btwn teeth and cheeks

Newborns have cheek pads that:

• Limit buccal space

• Help direct liquids down the middle of the oral cavity for safer swallowing

As cheek pads are lost in early childhood:

The buccal space enlarges.

Increased buccal space and neuromuscular development allows for:

More precise articulation.

Mastication (chewing) of more complex food textures

post-swallow aspiration risk

Food can collect in the buccal spaces

Oral Membranes

Inside of the mouth (except tongue, hard palate, and gums): lined with shiny squamous epithelium

Masticatory mucosa: covers the gums and hard palate

surface of the tongue: covered with specialized mucosa

Inside of the mouth (except tongue, hard palate, and gums) is lined with shiny squamous epithelium that:

• Produces surface liquid to keep the mouth moist

• Provides comfort and allows for smooth, rapid movement during speech

Masticatory mucosa covers the gums and hard palate:

Has collagen subflooring that makes the epithelium firmly attached to bone.

The surface of the tongue is covered with specialized mucosa that contains:

• Taste buds.

• Sensory nerve endings for temp and pressure detection.

Muscles of the Mandible (7)

Masseter

Temporalis

Internal (Medial) Pterygoid

External (Lateral) Pterygoid

Digastric

Mylohyoid

Geniohyoid

Masseter

ELEVATES (closes) and RETRACTS Mandible

muscle covering the outer surface of the mandibular ramus

Has two layers

• outer (larger)

• inner (smaller)

Temporalis

ELEVATES (closes) and RETRACTS Mandible

muscle that covers much of the side of the cranium (temporal bone)

Internal Pterygoid

ELEVATES (closes) mandible

• one-sided contraction = jaw moves toward opposite side (helps w/ chewing)

parallel to the masseter

together, they form a muscular sling that surrounds the angle of the mandible, strapping the ramus of the mandible to the skull

External Pterygoid

Slides condyle DOWN and FORWARD (helps open jaw and protrude it)

• one sided contraction = chin area moves toward opposite side (helps w/ chewing)

smaller muscle of the mandible

Digastric

LOWERS Mandible (opens mouth) and ELEVATES hyoid bone and larynx

Not directly attached to hyoid bone

similar to Mylohyoid and Geniohyoid

Mylohyoid

LOWERS mandible (opens mouth) and ELEVATES hyoid bone and larynx

Connected to lower structure of mandible

similar to Digastric and Geniohyoid

Geniohyoid

LOWERS mandible (opens mouth) and ELEVATES hyoid bone and larynx

Connected to lower structure of mandible

similar to Digastric and Mylohyoid

Muscles of the Mandible

complete

Movements of the Mandibular Muscles

Elevation and depression

Protrusion and retraction

Lateral movement

Muscles of the Tongue