infratemporal fossa

Question 1

Describe how the 4 muscles of mastication affect the mandible

What are the two nonclassic muscles of mastication which depress the mandible?

Answer 1

1. Temporalis - retrusion and elevation of the mandible
2. Masseter - elevation of the manidible
3. Lateral pterygoid - depression of the mandible and protrusion
4. Medial pterygoid - Elevation and protrusion

Unilateral contraction of the pterygoids leads to grinding of teeth.

—if the hyoid bone is stabilized—-

1. Anterior belly of the digastric
2. Mylohyoid

Question 2

Describe the temporomandibular joint

Answer 2

It is a modified hinge joint between the condyle of the mandible and the temporal bone.

It can allow for protrusion, retrusion, elevation and depression, and medial and lateral displacement.

The TMJ has two joint cavities separated by an articular disc which is attached to the lateral pterygoid so the disc moves with the mandible.

Question 3

Describe TMJ dislocation and the two kinds.

Answer 3

TMJ dislocation occurs when the condyle moves too anteriorly it can move superiorly and get stuck in a notch. That causes the temporalis and masseter to be unable to bring the condyle back and this is a dislocation

Unilateral- chin will deviate toward the normal side

Question 4

Describe the pathway of the middle meningeal artery

Answer 4

The middle meningeal artery is a branch off of the maxillary artery. As it travels superiorly the auriculotemporal nerve opens to allow the artery through and into the foramen spinosum.

Question 5

Besides the muscular branches to the classic muscles of mastication, what are the six other branches?

Answer 5

Sensory:
1. Buccal nerve - sensation of inner cheek

2. lingual - tongue
3. Inferior alveolar - teeth, gums
4. Mental nerve
5. Auriculotemporal nerve

Motor:

6. Nerve to mylohyoid.

Question 6

Describe the pathway of the parasympathetics to the parotid gland.

Answer 6

Preganglionic parasympathetics run in the lesser petrosal nerve to the otic ganglion.

It synapses and then the postganglionic sympathetics run in the auriculotemporal nerve to the parotid gland.

Question 7

Describe the parasympathetic innervation of the submandibular and sublingual gland.

Answer 7

Preganglionic parasympathetics from the facial nerve continue running in the chorda tympani branch which joins the lingual nerve.

Off of the lingual nerve is the submandibular ganglion where it synapses and then the postganglionics run with the lingual nerve to the glands.

btw - chorda tympani also carries the anterior 2/3 of taste.

Question 8

Describe the two muscles of the inner ear

Answer 8

1. Tensor tympani - attaches to the malleulus which will tighten the tympanic membrane (mandibular division)
2. Stapedius - attaches to the stapes (facial nerve)

Question 9

Describe the walls of the tympanic cavity

Answer 9

1. Tympanic membrane
2. Tegmen tympani - separating the middle cranial fossa and the middle ear
3. Jugulum - separating the middle ear and the internal jugular vein
4. Oval window - opening filled with stapes
5. Round window- membrane