SCS 3655 Study Group - Lecture 30, Part 2 (Mouth and Nose)

Which bones contribute to the lateral wall of the nasal cavity?

• Frontal bone

  Nasal bone

  Ethmoid bone

  Vomer

  Maxilla

• Ethmoid bone

  Sphenoid bone

  Palatine bone

  Lacrimal bone

  Maxilla

• Ethmoid bone

  Maxilla

  Lacrimal bone

  Inferior concha

  Palatine bone

• Sphenoid bone

  Ethmoid bone

  Palatine bone

  Vomer

  Maxilla

Answer explanation

- Frontal bone is not part of the nasal cavity

- Vomer is only part of the medial wall

- Sphenoid bone contributes medial pterygoid plate

- Palatine bone contributes perpendicular plate

Select the correct answer(s) below.

• a) The nasolacrimal duct opens into the middle meatus of the nasal cavity.

• b) A posterior coronal view of the head at a level that runs through the pharynx will show the choanae.

• c) The sublingual ducts' papillae can be seen at either side of the lingual frenulum.

• d) The sphenoidal air sinus opens into the nose via the superior meatus between the roof of the nose and the superior concha.

Answer explanation

a) false - inferior meatus.

b) true - apertures between nasopharynx and nasal cavity.

c) false - too small to see. Submandibular would be true

d) false - spheno-ethmoidal recess, not superior meatus.

Select the incorrect answer(s).

• The superficial head of masseter inserts on the ramus of the mandible and originates from the maxillary process of the zygomatic bone.

• The medial pterygoid muscle attaches to the infero-medial surface of the mandible.

• The temporalis muscle originates on the temporal fossa and inserts on the head of the mandible, allowing it to elevate and retract the mandible.

• All muscles of mastication receive motor innervation solely from the trigeminal nerve.

Which muscles of mastication are able to retract the mandible?

• Masseter

• Temporalis

• Medial Pterygoid

• Lateral Pterygoid

Answer explanation

Deep head of the masseter and posterior fibers of the temporalis can retract.

Which muscles are capable of protracting (AKA protruding) the mandible?

• Masseter

• Temporalis

• Lateral Pterygoid

• Medial Pterygoid

Answer explanation

Masseter both protrudes and retracts, so it's a weak effect.

Temporalis only elevates and retracts (+ weak lateral excursion).

Both Pterygoids protrude.

Select the correct option(s).

• a) The nasal cavity is innervated by general sensory fibers from CN V & CN VII.

• b) The temporo-mandibular joint is formed by the temporal bone and the coronoid process of the mandible.

• c) The nasal cavity receives blood supply from both the facial artery and the maxillary artery.

• d) The nasal cavity receives blood supply from only the external carotid artery.

Answer explanation

a) false - only trigeminal nerve

b) false - head/condylar process

c) True

d) false - external & internal carotid

Select the correct option(s) below.

• a) Temporalis assists the pterygoids in lateral excursion of the mandible.

• b) The Eustachian tubes open into the lateral wall of the nasopharynx, posterior to the inferior concha.

• c) The posterior superior lateral nasal nerves branch from V2 and pass through the sphenopalatine foramen.

• d) An anastomosis of branches of the anterior ethmoidal, superior labial, and sphenopalatine arteries in the lateral wall of the nasal cavity is a typical site of nosebleeds.

Answer explanation

a) false - only the pterygoids function in lateral excursion

b) true

c) true

d) false - medial wall aka septum