LING 314: WEEK 10

mental symphysis

chin joint

• where the mandible formed - originally two separate bones that fused together in early years

label the parts of the mandible

1. condylar process

2. mandibular notch

3. coronoid process

4. ramus

5. angle of mandible

6. body

7. mental/mandibular symphysis

mental protuberance

chin

• a triangular projection on the anterior part of the mandible located at the midline

mental spines

located in the midline of the lingual (inner) surface of the mandible, specifically on the mandubular symphysis

• superior: origin for the genioglossus muscle

• inferior: origin for the geniohyoid muscle

mylohyoid line

temporomandibular joint (TMJ)

connects the mandible to the temporal bone of skull

• consists of condyle of mandible and mandibular fossa of temporal bone

• cushioned by a fibrous articulator disk for smooth movement

mandibular foramen

vessels supply blood to lower teeth and surrounding bone

• located on internal surface of the ramus of mandible

• an opening that serves as entry point for inferior alveolar nerve and vessels

mental foramen

• situated on external surface of mandible, near apex of mandibular premolar teeth

• a small opening that allows passage of mental nerve and blood vessels

how are jaw muscles categorized?

elevators (lifters) and depressors (lowerers)

masseter muscle

elevates the mandible (jaw closing)

• divided into deep head and shallow head

• origin: zygomatic arch

• insertion: ramus and angle of mandible

temporal fossa

shallow depression on lateral aspect of skull

• acts as origin of temporalis muscle

bony boundaries of temporal fossa

• frontal bone (inferior lateral part)

• parietal bone (inferior portion)

• temporal bone (squamous part)

• sphenoid bone

temporalis muscle

elevates and retracts the mandible (fast closing)

• origin: temporal fossa

• insertion: coronoid process of mandible

• fan like shape allows for wide-range of movements

  • vertical fibers: elevate mandible

  • horizontally oriented fibers: retract mandible + pulls coronoid process sidewats

which one is false about temporalis muscle

a. it is a muscle of mastication

b. it depresses mandible during jaw opening

c. its origin intersects with frontal bone

d. it inserts on coronoid process of mandible

B

medial pterygoid muscle

elevates mandible

• origin: sphenoid bone, palatine bone, and maxilla

• insertion: inner surface of mandible

lateral pterygoid

controls side-to-side movements of jaw

• aids in protrusion of jaw

• origin: sphenoid bone and maxilla

• insertion: TMJ disc and condyle of mandible

jaw depressor muscles

responsible for lowering the mandible

• also stabilize the hyoid bone and assist in tongue movements

• includes:

  • anterior belly of digastric muscle

  • mylohyoid

  • geniohyoid

extrinsic tongue muscles

connect tongue to surrouding structures, enables complex motions

• genioglossus

• palatoglossus

• hyoglossus

• styloglossus

genioglossus (GG)

protacts, depresses, and can groove the tongue

• origin: mental spine of mandible

• insertion: throughout tongue, from tip to root

• 3 sections

  • anterior (GGa): lowers and retracts tongue front

  • middle (GGm): lowers and pulls forward tongue body; creates groove

  • posterior (GGp): pulls tongue root forward

palatoglossus (PG)

elevates the tongue and assists in uvular constrictions

• narrows oropharyngeal isthmus

• origin: palatine aponeurosis

• insertion: sides of tongue body

hyoglossus (HG)

pulls tongue down and back, ESPECIALLY back of tongue

• origin: greater horn of hyoid bone

• insertion: sides of tongue

styloglossus (SG)

traditionally thought to raise and retract tongue

• role in speech is under review

• origin: styloid process of the temporal bone

• insertion: sides of tongue, interlocks with intrinsic tongue muscles

what is the significance of the mental spines in muscle attachment?

a. both superior and inferior spines are origins for the mylohyoid

b. they are purely vestigial and have no muscular function

c. superior mental spines originate the genioglossus; inferior spines originate the geniohyoid

c

true or false:

the massete muscle, like the temporalis, inserts on the coronoid process of the mandible, and primarily contirbutes to jaw retraction

false

true or false:

john is looking at a midsagittal slice/image of the tongue of a subject and notices a forward movement of the tongue body.

• the anterior fibers of the genioglssus muscle that can create such a movement.

false

which of the following statements is TRUE?

a. the medial pterygoid originates on the mandible and inserts on the temporal bone

b. the temporalis originates on the temporal fossa and inserts on the coronoid process of the mandible

c. the masseter originates on the mandible and inserts on the zygomatic arch

d. the lateral pterygoid elevates the mandible during chewing

b

during an articulatory experiment, a researcher observes strong activation of a tongue muscle that rigniates on the mandible and inserts into the body of that tongue

genioglossus