A5 - The mandibula, art. temporomandibularis, ossa hyoidea, muscles of mastication

Question 1

Give the muscles of mastication

Answer 1

Adductors (lift the mandible - bite)

• M. masseter
• M. temporalis
• M. pterygoideus

Abductors (opens the mouth)

• M. digastricus
• M. mylohyoideus
• M. stylohyoideus

Question 2

M. masseter

Answer 2

• Origin: Arcus zygomaticus, ventral border. It has three insercting layers
• Insertion: Fossa masseterica of mandible (lateral surface)
• Action: Closes jaw

Question 3

M. temporalis

Answer 3

• Origin:
  
  • From fossa temporalis and its border:
    
    • Linea temporalis
    • Crista saggitalis externa
    • Crista nuca
  • Arcus zygomaticus, dorasl edge
• Insertion: Processus coronoideus on mandible
• Action: Raises mandible, closes jaw

Question 4

M. pterygoideus medialis

Answer 4

• Origin: Fossa pterygopalatina (from sphenoid, palatine and pterygoid bones)
• Insertion: Fossa pterygoidea (medially, below foramen mandibulae)
• Action:
  
  • Grinding movements
  • Closes jaw

Question 5

M. ptereygoideus lateralis

Answer 5

• Origin: Ventral to canalis alaris and fissura orbitalis from os sphenoidale
• Insertion: Fovea pterygoidea (medially next to processus condylaris of mandible)
• Action:
  
  • Grinding movements
  • Closes jaw

Question 6

M. digastricus

Answer 6

• Origin: Processus paracondylaris of os occipitale
• Insertion: Ventral-ventromedial border of mandible
• Action: Opens mouth
• Innervation:
  
  • ​N. mandibularis (V₁)
  • N. facialis (VII)

Question 7

Give the facial musculature

Answer 7

Question 8

Give the muscles of lips and cheeks

Answer 8

1. M. orbicularis oris
2. Mm. incisivi
3. M. levator nasolabialis
4. M. levator labii maxillaris
5. M. caninus
6. M. depressor labii
7. M. mentalis
8. M. zygomaticus
9. M. buccinator

Question 9

Give the muscles of the eyelids

Answer 9

1. M. orbicularis oculi
2. M. superciliaaris/M. levator anguli oculimedialis
3. M. retractor/M. retractor anguli oculilateralis

Question 10

Give the muscles of the external ear

Answer 10

1. M. scutularis
2. M. parotidoauricularis
3. Abductors – Mm. auricularis caudalis
4. Elevators – Mm. auricularis dorsalis
5. Adductors – Mm. auricularis rostralis
6. Rotators – Mm. auricularis profundus
7. Auditory meatus muscle
8. Muscles of the conchal cartilage

Question 11

Mandible

Draw the mandible

Answer 11

Question 12

Mandible

Structures to mention

Answer 12

Corpus mandibulae

• Pars incisiva
  
  • Arcus alveolaris
  • Canales alveolares
• Pars molaris
• Margo alveolaris
• Margo ventralis
• Incisura vasorum facialium (Ø ca)
• Foramen mentale (eq, bo)
• Foramina mentalia (ca, su)
• Facies labialis
• Facies buccalis
• Facies lingualis
  
  • Linea mylohyoidea
• Alveoli dentales
• Septa interalveolaria
  
  • Septa interradicularia
• Margo interalveolaris [diastema]
• Juga alveolaria

Ramus mandibulae

• Angulus mandibulae
• Processus angularis (ca)
• Tuberositas m. sternomandibularis (eq)
• Fossa masseterica
• Fossa pterygoidea
• Foramen mandibulae
• Canalis mandibulae
• Canalis mandibuloincisivus
• Processus coronoideus
• Processus condylaris
• Caput mandibulae
• Collum mandibulae
• Fovea pterygoidea

Question 13

Mandible

Give the interspecies differences of the mandible

Answer 13

• Curved margo ventralis (ru, ca)
• Incisura vasorum facialum (ø ca)
• For. mentale (eq, bo)
• Forr. mentalia (ca, sus)
• Proc. angularis (ca)
• Tuberositas m. sternomandibularis (eq)
• Diastema (ø ca)??????

Question 14

Mandible

Give the channels of the mandible, and their role

Answer 14

• Canalis mandibularis
  
  • For. mandibularis (med.) → canalis mandibularis → for. mentale/forr. mentalia (lat.) (su: lat+med)
  • For n. alveolaris inferior
• Canales alveolares
  
  • Given off by canalis mandibulairs
  • Runs to the lower teeth (canine and incisors)
  • Contains nerves and vessels
• Canalis mandibuloincisivus
  
  • When canalis mandibulae arrives at the incisors, it turns back to communicate with the mental foramen, giving off canalis mandibuloincisivus
  • Runs to the cavities containing incisors
  • Carries branches of n. alveolaris inferior

Question 15

Give the features of the temporomandibular joint, art. temporomandibularis

Answer 15

• Synovial
• Condylar (biaxial)
• Between ramus mandibulae and pars squamosa of os temporale
• Articular convexity:
  
  • Caput mandibulae of proc. condylaris of mandibula
• Articular concavity:
  
  • Processus retroarticularis of temporal bone
• Movements:
  
  • Opening and closing (hinge-movement) (lig. caudale)
  • Grinding – lateral movement (lig. laterale)

Structures:

• Capsula articularis
• Discus articularis (Dividing the joint into two chambers)
• Lig. laterale (Ligament of the lateral surface of capsula articularis)
• Lig. caudale (eq, bo) (Elastic ligament from processus retroarticularis → collum mandibulae)

Question 16

Give the ligaments of the temporomandibular joint

Answer 16

1. Lig. laterale
   
   • Strengthens the joint capsule
2. Lig. caudale (ø ca, sus)
   
   • Between processus retroarticularis and collum mandibularis

Question 17

Os hyoideum

Location

Answer 17

• Between the two rami of the mandibula
• Rostrally: embedded in the radix linguae
• Caudally: connected with the larynx
• Dorsally: articulates with os temporale

Suspensory apparatus:

• Connects os hyoideum to os temporale
• Connection achieved by:
  
  • Ca: processus mastoideus of pars petrosa
  • Eq, ru: processus styloideus of tympanicum
  • Sus: crista nucha of squamous temproal
• Parts of the suspensory apparatus:
  
  • Tympanohyoideum
  • Stylohyoideum
  • Epihyoideum

Question 18

Os hyoideum

Structures to mention

Answer 18

• Basihyoideum
  
  • Processus lingualis (eq, bo)
• Keratohyoideum
• Thyreohyoideum
• Epihyoideum
• Stylohyoideum
  
  • Angulus stylohyoideus (eq, bo)
• Tympanohyoideum

Question 19

Os hyoideum

Draw os hyoideum

Answer 19

Question 20

Os hyoideum

Give the interspecies differences of os hyoideum

Answer 20

• Proc. lingalis (eq, bo)
• Angulus stylohyoideus (eq, bo)