SCID 243 - Quiz 4 - Infratemporal Fossa & Oral Cavity

1. The surgical removal of a metastatic tumor in the infratemporal fossa caused an intense hemorrhage. The surgeon clamped the main source of arterial supply to the area, which is the: ______

Internal carotid

Lingual

Maxillary

Posterior auricular

Superficial temporal

The maxillary artery is one of the terminal branches of the external carotid artery. It enters the infratemporal fossa and is the major source of blood for that region.

Explanation

The maxillary artery is one of the terminal branches of the external carotid artery. It enters the infratemporal fossa and is the major source of blood for that region.

2. The cell bodies of the postganglionic parasympathetic neurons innervating the sublingual gland are found in which of the following ganglia?

Ciliary

Otic

Submandibular

Superior cervical

Trigeminal

The submandibular ganglion contains the cell bodies of the postganglionic parasympathetic neurons that innervate the sublingual and submandibular gland.

Explanation

The submandibular ganglion contains the cell bodies of the postganglionic parasympathetic neurons that innervate the sublingual and submandibular gland.

3. The lesser petrosal nerve carries preganglionic parasympathetic fibers to the: _______

Geniculate ganglion

Otic ganglion

Submandibular ganglion

Ciliary ganglion

The lesser petrosal nerve is a branch of the glossopharyngeal nerve (CN IX). The lesser petrosal nerve carries presynaptic parasympathetic fibers to the otic ganglion. These fibers synapse in the otic ganglion, and the postsynaptic fibers travel on the auriculotemporal nerve to innervate the parotid gland.

Explanation

The lesser petrosal nerve is a branch of the glossopharyngeal nerve (CN IX). The lesser petrosal nerve carries presynaptic parasympathetic fibers to the otic ganglion. These fibers synapse in the otic ganglion, and the postsynaptic fibers travel on the auriculotemporal nerve to innervate the parotid gland.

4. Damage of the lingual nerve before it is joined by the chorda tympani in the infratemporal fossa would cause loss of: ________

General sensation to the anterior two thirds of the tongue

General sensation to the posterior one third of the tongue

Secretion of the submandibular gland

Taste sensation from the anterior two thirds of the tongue

Taste sensation from the posterior one third of the tongue

The lingual nerve is a branch of V3, the mandibular division of the trigeminal nerve. It transmits general sensation from the anterior 2/3 of the tongue. Damaging this nerve anywhere along its course would cause someone to lose general sensation to the anterior 2/3 of the tongue. The chorda tympani is a branch of VII--it carries taste fibers to the anterior 2/3 of the tongue and presynaptic parasympathetic fibers to the submandibular ganglion.

Explanation

The lingual nerve is a branch of V3, the mandibular division of the trigeminal nerve. It transmits general sensation from the anterior 2/3 of the tongue. Damaging this nerve anywhere along its course would cause someone to lose general sensation to the anterior 2/3 of the tongue. The chorda tympani is a branch of VII--it carries taste fibers to the anterior 2/3 of the tongue and presynaptic parasympathetic fibers to the submandibular ganglion.

5. A 38-year-old patient complained of acute dental pain. The attending dentist found penetrating dental caries (dental decay) affecting one of the mandibular molar teeth. Which nerve would the dentist need to anesthetize to work on that tooth?

Lingual

Inferior alveolar

Buccal

Mental

Mylohyoid

The inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve (V3). It penetrates the mandibular foramen and is the sensory nerve for the mandible and all mandibular teeth. This is the nerve anesthetized by dentists working on the mandibular teeth. It is anesthetized near the mandibular foramen, so sensory nerves from branches distal to that point would be blocked.

Explanation

The inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve (V3). It penetrates the mandibular foramen and is the sensory nerve for the mandible and all mandibular teeth. This is the nerve anesthetized by dentists working on the mandibular teeth. It is anesthetized near the mandibular foramen, so sensory nerves from branches distal to that point would be blocked.

6. The chorda tympani contains which component before it joins the lingual nerve?

Preganglionic sympathetics

Postganglionic sympathetics

Preganglionic parasympathetics

Postganglionic parasympathetics

Taste fibers to the posterior third of the tongue

The chorda tympani contains preganglionic parasympathetic nerves that go to the submandibular ganglion. These preganglionic parasympathetics synapse in the submandibular ganglion and then provide secretomotor innervation to the submandibular and sublingual glands. The chorda tympani also contains taste fibers to the anterior 2/3 of the tongue, but not to the posterior 1/3.

Explanation

The chorda tympani contains preganglionic parasympathetic nerves that go to the submandibular ganglion. These preganglionic parasympathetics synapse in the submandibular ganglion and then provide secretomotor innervation to the submandibular and sublingual glands. The chorda tympani also contains taste fibers to the anterior 2/3 of the tongue, but not to the posterior 1/3.

7. Which of the following suprahyoid muscles would be paralyzed if the inferior alveolar nerve were severed at its origin?

Geniohyoid m.

Hyoglossus m.

Mylohyoid m.

Stylohyoid m.

Mylohyoid is innervated by the nerve to mylohyoid, which is a branch of the inferior alveolar nerve. The inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve.

Explanation

Mylohyoid is innervated by the nerve to mylohyoid, which is a branch of the inferior alveolar nerve. The inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve.

8. Cutting of the hypoglossal nerve in the hypoglossal canal would not interrupt the nerve supply to the: __________

Hyoglossus muscle

Genioglossus muscle

Palatoglossus muscle

Styloglossus muscle

All of the tongue muscles are innervated by the hypoglossal nerve. So, hyoglossus, genioglossus, and styloglossus are all innervated by the hypoglossal nerve. Although palatoglossus sounds like a tongue muscle, it is a palatal muscle, innervated by the vagus nerve. (Palatoglossus is the only "glossus" muscle that is not innervated by the hypoglossal nerve.)

Explanation

All of the tongue muscles are innervated by the hypoglossal nerve. So, hyoglossus, genioglossus, and styloglossus are all innervated by the hypoglossal nerve. Although palatoglossus sounds like a tongue muscle, it is a palatal muscle, innervated by the vagus nerve. (Palatoglossus is the only "glossus" muscle that is not innervated by the hypoglossal nerve.)

9. A cranial fracture through the foramen ovale that compresses the enclosed nerve, will have an effect on all muscles EXCEPT : ________

Tensor tympani

Masseter

Buccinator

Mylohyoid

Temporalis

Buccinator is a muscle on the side of the cheek which is innervated by the facial nerve (VII).

Explanation

Buccinator is a muscle on the side of the cheek which is innervated by the facial nerve (VII).

10. In acute inflammation (arthritis) of the TMJ, the muscle most likely to be affected by the inflammatory process is the: __________

Temporal

Medial pterygoid

Masseter

Lateral pterygoid

The inferior head of the lateral pterygoid inserts into the neck of the mandible, while the superior head of the lateral pterygoid inserts directly into the capsule and articular disk of the temporomandibular joint. So, this muscle would be affected by arthritis of the joint.

Explanation

The inferior head of the lateral pterygoid inserts into the neck of the mandible, while the superior head of the lateral pterygoid inserts directly into the capsule and articular disk of the temporomandibular joint. So, this muscle would be affected by arthritis of the joint.

11. A patient who experienced bilateral anterior dislocation of the jaw (temporomandibular joints) could not swallow or talk since the mouth was held open. What is the position of the condyles of the mandible as a result of the dislocation?

Against the external acoustic meatus

Against the anterior slope of the articular eminence

Against the posterior slope of the articular eminence

In the mandibular fossa

In the pterygoid fossa

The TMJ may dislocate anteriorly due to excessive contraction of the lateral pterygoids. This could happen if someone yawned too much or took a large bite of food. So, you want to look for the answer here that represents anterior movement of the jaw. Answer B, against the anterior slope of the articular eminence, is anterior to the normal position of the mandible, so that's the correct answer.

Explanation

The TMJ may dislocate anteriorly due to excessive contraction of the lateral pterygoids. This could happen if someone yawned too much or took a large bite of food. So, you want to look for the answer here that represents anterior movement of the jaw. Answer B, against the anterior slope of the articular eminence, is anterior to the normal position of the mandible, so that's the correct answer.

12. The difficulty in swallowing was due to involvement of which muscle that elevates the tongue?

Genioglossus

Hyoglossus

Styloglossus

Stylohyoid

Stylopharyngeus

Styloglossus retracts and elevates the tongue. Genioglossus is a large, fan shaped muscle with many actions: its inferior fibers protrude the tongue, its middle fibers depress the tongue, and its superior fibers draw the tip back and down. Hyoglossus retracts and depresses the tongue. All of these muscles are innervated by the hypoglossal nerve (CN XII).

Explanation

Styloglossus retracts and elevates the tongue. Genioglossus is a large, fan shaped muscle with many actions: its inferior fibers protrude the tongue, its middle fibers depress the tongue, and its superior fibers draw the tip back and down. Hyoglossus retracts and depresses the tongue. All of these muscles are innervated by the hypoglossal nerve (CN XII).

13. Paralysis of which of the following muscles would impede retraction of the mandible?

Buccinator

Lateral pterygoid, lower portion

Lateral pterygoid, upper portion

Medial pterygoid

Temporalis

Temporalis is the important muscle for retracting the mandible!

Explanation

Temporalis is the important muscle for retracting the mandible!

14. The cell bodies of the taste fibers from the anterior two-thirds of the tongue are located in the: _________

Geniculate ganglion

Otic ganglion

Pterygopalatine ganglion

Submandibular ganglion

Trigeminal ganglion

The geniculate ganglion is the sensory ganglion of the facial nerve--it holds the cell bodies of the neurons that carry taste sensations from the anterior 2/3 of the tongue. These fibers then travel on the chorda tympani, which carries the fibers to the lingual nerve.

Explanation

The geniculate ganglion is the sensory ganglion of the facial nerve--it holds the cell bodies of the neurons that carry taste sensations from the anterior 2/3 of the tongue. These fibers then travel on the chorda tympani, which carries the fibers to the lingual nerve.

15. When one presses the tongue tip against the anterior (incisor) teeth, which of the following muscles must contract?

Styloglossus

Hyoglossus

Genioglossus

Superior longitudinal

Verticalis

Genioglossus is a large, fan shaped muscle with many actions: its inferior fibers protrude the tongue, its middle fibers depress the tongue, and its superior fibers draw the tip back and down. So, since the tongue is being protruded, the inferior fibers of genioglossus must be contracting.

Explanation

Genioglossus is a large, fan shaped muscle with many actions: its inferior fibers protrude the tongue, its middle fibers depress the tongue, and its superior fibers draw the tip back and down. So, since the tongue is being protruded, the inferior fibers of genioglossus must be contracting.