Deep Face and Infratemportal Fossa

Question 1

List the various muscles of mastication.

What is their innervation?

Answer 1

1. Temporalis Muscle - Anterior and Posterior Deep Temporal Nerves
2. Masseter Muscle - CN V
3. Medial Pterygoid Muscle - CN V
4. Lateral Pterygoid Muscle - CN V
5. Buccinator Muscle - CN VII

Question 2

Describe the importance of the Sphenomandibular Ligament.

Answer 2

Inferior Alveolar nerve and artery pass between this ligament and the NECK of the Mandible

Question 3

Describe the embryological origin for the muscles of mastication.

Answer 3

Derived from the 1st Branchial Arch

Arterial Supply: Branches of the SECOND part of the MAXILLARY artery

Innervation: Branches of the mandibular division of CN V

*** Buccinator is considered an assossory muscle of mastication (CN VII)

Question 4

Which structure will pierce the Buccinator Muscle?

Answer 4

Parotid Duct

Question 5

Which two muscles will close the mouth?

Answer 5

1. Masseter
2. Medial Pterygoid

Question 6

Which muscle will open the mouth?

Which structures are going to pass through the two heads of the Lateral Pterygoid Muscles?

Which structures are going to pass through the lateral and medial Pterygoid Muscles?

Answer 6

Lateral Pterygoid (has 2 heads)

*** Maxillary Artery and Long Buccal Branch of CN V usually passes through the two heads of the Lateral Pterygoid

*** Inferior Alveolar and Lingual Nerves

Question 7

Describe the Jaw-Jerk Reflex.

Answer 7

Focus is on the Masseter Muscle

Question 8

Describe the different actions of the muscles of mastication.

Answer 8

Question 9

Describe the different joints within the Temporomandibular Joint.

Answer 9

Superior Joint: Gliding Joint (for wide opening of the mouth) between the mandibular fossa and articular tubercle
- Capsule is thin and LOOSE

Inferior Joint: Hinge Joint between the articular disk and the mandibular condyle
- Capsule is strong and TIGHT

Articular Disk: Attached to the SPHENOMENISCUS muscle and the strong Lateral Ligament

*** If your mouth slips open, you can pull the jaw FORWARD and DOWN in order to slip it back into place

Question 10

Describe the changes in the Mental Angle with Age.

Answer 10

Newborn: Mental angle of 175 degrees because it does not have any teeth and the alveolar bone is only a shell and the basilar bone is thin

4 year old child: Mental Angle is about 140 degrees

Adult: Mental Angle is about 110-120 degrees because of DENTITION

Senior Patient: Mental Angle is about 140 degrees due to losing teeth with corresponding alveolar bone resorption

Question 11

Describe the different types of Mandibular Fractures.

Answer 11

Fracture of Neck = Big Hematoma on the side of the face

Fracture of Ramus = Numbness on 1/2 of tongue or Numbness on chin (Inferior Alveolar N.)

Fracture of Body = Numbness on chin

Question 12

Name the different parts of the Mandibular Nerve (V3).

Answer 12

Question 13

What is the terminal branch of the Maxillary Artery?

Answer 13

Sphenopalatine

*** Cheap Blood Supply to the Posterior 2/3 of the Nasal Cavity

*** Bifurcates into a Posterior Septal and Posterior Lateral Nasal

Question 14

Answer 14