Skull Osteology, Muscles of Mastication, Infratemporal Fossa

Question 1

Answer 1

Question 2

Name the holes and what goes through each (in red).

Answer 2

1. Foramen rotundum (V2)
2. Foramen ovale (V3)
3. Foramen spinosum (middle meningeal artery)

Question 3

Answer 3

9 (not in answer photo) is the mylohyoid line

Question 4

Name the origin, insertion, and action(s) of the masseter muscle.

Answer 4

Origin: zygomatic arch

Insertion: ramus of the mandible

Action: elevates mandible (closes jaw)

Question 5

Name the origin, insertion, and action(s) of the temporalis muscle.

Answer 5

Origin: temporal fossa

Insertion: medial aspect of the coronoid process

Actions: elevate, retract, laterally move mandible

Question 6

Name the origin, insertion, and action(s) of the medial pterygoid muscle.

Answer 6

Origin: medial aspect of the lateral pterygoid plate

Insertion: medial aspect of the mandibular angle

Action: elevate mandible (close jaw)

Question 7

Name the origin, insertion, and action(s) of the lateral pterygoid muscle.

Answer 7

Origin: lateral aspect of the lateral pterygoid plate.

Insertion: anterior aspect of the condylar process.

Action: protrude mandible.

Question 8

Name the origin, insertion, and action(s) of the anterior belly of the digastric.

Answer 8

Origin: digastric fossa of the mandible

Insertion: intermediate tendon/fascial sling on the hyoid

Action: elevate hyoid, depress mandible

Question 9

Name the origin, insertion, and action(s) of the posterior belly of the digastric.

Answer 9

Origin: mastoid notch

Insertion: intermediate tendon/fascial sling on the hyoid

Action: elevate hyoid, depress mandible (open jaw)

Question 10

Name the origin, insertion, and action(s) of the stylohyoid muscle.

Answer 10

Origin: styloid process of the temporal bone

Insertion: body of the hyoid

Action: elevate hyoid bone

Question 11

Name the origin, insertion, and action(s) of the mylohyoid muscle.

Answer 11

Origin: mylohyoid line on mandible

Insertion: hyoid bone

Action: elevate floor of the oral cavity

Question 12

Name the origin, insertion, and action(s) of the geniohyoid

Answer 12

Origin: inferior genial spine of the mandible

Insertion: hyoid bone

Actions: open jaw, protrude hyoid

Question 13

What is the action of the buccinator muscle?

Answer 13

Contracts during chewing to keep food in the oral cavity.

Question 14

What is the motor nerve for the muscles of mastication?

Answer 14

CN V3

Question 15

Describe the pathway an infectious agent could take from the upper teeth –> brain.

Answer 15

Upper tooth –> pterygoid plexus of veins –> emissary vein superiorly –> cavernous sinus

Question 16

Name the hole/fissure/foramen that provide a route of communication between the pterygopalatine fossa and the…

1. Infratemporal fossa
2. Middle cranial fossa
3. Nasal cavity
4. Orbit
5. Palate

Answer 16

1. Infratemporal fossa: Pterygomaxillary fissure
2. Middle cranial fossa: Foramen rotundum
3. Nasal cavity: Sphenopalatine foramen
4. Orbit: Inferior orbital fissure
5. Palate: Palatine canal (greater and lesser palatine foramen)

Question 17

After V3 exits foramen _______, it divides into four large, grossly visible nerves that can be found in the infratemporal fossa. Name them. What are the spatial relationships between these nerves and the lateral pterygoid muscle?

Answer 17

Foramen ovale

Splits into the [long] buccal nerve, lingual nerve, inferior alveolar nerve, and auriculotemporal nerve.

Long buccal nerve (sensory branch of V3) exits between the two heads of the lateral pterygoid, while the inferior alveolar and lingual nerves exit below the inferior head of the lateral pterygoid muscle.