Temporal and Infratemporal Fossa

Question 1

The ramus is the condyle which articulates with the temporal bone through an _____ at the ____ ____.

Answer 1

articular disc at the mandibular fossa

Question 2

What is the insertion of the temporalis muscle?

Answer 2

the coronoid process

Question 3

What artery and nerve passes through the mandibular foramen?

Answer 3

the inferior alveolar artery and nerve

Question 4

What artery and nerve branch off before entering the mandibular foramen?

Answer 4

artery and nerve to the mylohyoid.

Question 5

As the alveolar artery nerve pass through from the mandibular
foramen to the mental foramen, what do they innervate/supply?
What do they called as they exit the menal foramen?

Answer 5

Supply and innervate the mandibular teeth. Become the mental artery and nerve.

Question 6

Where does the sphenomandibular ligament attach?

Answer 6

the bony lingula

Question 7

Describe the insertion of the masseter and the medial pterygoid muscle?

Answer 7

The masseter muscle inserts on the lateral surface of the ramus and angle, while the medial pterygoid muscle inserts on the medial surface inferior to the mandibular foramen.

Question 8

What are four muscles of mastication? What are they innervated by?

Answer 8

temporalis
masseter,
medial and lateral pterygoids.
the motor branch of the mandibular nerve (CN V3). (Netter 54, 55):

Question 9

What muscles produce each movement? elevation
depression
protrusion
Retraction
Side to Side

Answer 9

elevation: the temporalis, masseter, & medial pterygoid muscles
Depression: mylohyoid, digastric, geniohyoid
Protrusion: lateral pterygoid (assisted somewhat by medial pterygoid)
Retraction: the posterior, horizontal fibers of temporalis (assisted by digastric and geniohyoid)
Side to Side: the pterygoids

Question 10

What is the origination and insertion of the Temporalis Muscle? Temporalis Fascia?

Answer 10

• The temporalis muscle originates temporal fossa which includes temporal, parietal, frontal and sphenoid. Inserts on the coronoid process of the mandible
• temporalis fascia arises from the superior temporal line (black dotted line) and inserts on and supports the zygomatic arch, resisting the inferior pull of the masseter muscle, which originates on the zygomatic arch and inserts on the lateral aspect of the ramus and angle of the mandible.

Question 11

The nerve and artery to the masseter pass medial or lateral through the mandibular notch? Which cranial nerve is this?

Answer 11

the artery and nerve (from CN V3) to the masseter passing laterally through the mandibular notch.

Question 12

What muscle does the parotid duct pierce? Where does the duct empty? What nerve innervates this muscle?

Answer 12

The parotid duct pierces the buccinator muscle (innervated by CN VII) to drain into the oral cavity opposite the second maxillary molar tooth.

Question 13

Where is the pituitary gland resting?

Answer 13

in the sella turcica.

Question 14

What foramen is the blue fibrocartilage passing? What nerve passes through this fibrocartilage?

Answer 14

fibrocartilage fills the foramen lacerum with the internal carotid artery just superior to it; the nerve of the pterygoid canal travels through the cartilage in an anteromedial direction.

Question 15

What nerve innervates the pterygoid muscles?

Answer 15

CN V3 (muscles of mastication)

Question 16

TMJ = temporomandibular joint (note that it contains a fibrous articular disc).

Answer 16

TMJ = temporomandibular joint (note that it contains a fibrous articular disc).

Question 17

Where are the ptyerygoid muscles located and where do they originate? Where do they insert? What are they innervated by?

Answer 17

•located in the infratemporal fossa
•originate from the medial and lateral surfaces of the lateral pterygoid
plate of the sphenoid bone respectively.
• The medial pterygoid inserts on the medial side of the ramus and angle
of the mandible inferior to the mandibular foramen
•the lateral pterygoid inserts onto the capsule and articular disc of the TMJ and the neck of the mandible (pterygoid fovea).
•t he motor branch of the mandibular nerve.

Question 18

What happens to jaw position if one lateral pterygoid muscle is
paralyzed?

Answer 18

protrude toward the side of the paralyzed muscle

Question 19

What is the course of the sphenomandibular ligament? At what jaw position is it fully taught?

Answer 19

from the spine of the sphenoid to the lingula on the mandibular ramus and becomes fully taut when the jaw is half open.

Question 20

What is the stylomandibular ligament a remnant of?

Answer 20

an insignificant thickening of the deep cervical fascia.

Question 21

What are the location and boundaries of the Infratemporal fossa?

Answer 21

an extracranial area inferior to the temporal fossa and the zygomatic arch.
deep to the ramus of the mandible
posterior to the tuberosity of the maxilla
lateral to the lateral pterygoid plate and anterior to the styloid process.
is bounded superiorly by the infratemporal crest of the greater wing of the sphenoid bone and is open inferiorly.

Question 22

What are the muscles (2)? Artery? Nerves (2)? Nerve plexus? And parasympathetic ganglion? That are found within the infratemporal fossa?

Answer 22

the two pterygoid muscles
the maxillary artery
the mandibular nerve (V3) and the chorda tympani nerve
the pterygoid venous plexus
parasympathetic otic ganglion.

Question 23

What is the course of the Maxillary Artery?

Answer 23

It originates within the deep lobe of the parotid gland and travels across the infratemporal fossa and passes through the pterygomaxillary fissure (blue star) into the pterygopalatine fossa.

Question 24

What are the two most important branches that arise from the Maxillary artery proximal to the pterygomaxillary fissure?

Answer 24

the middle meningeal and inferior alveolar arteries arise from the first portion of the artery.

Question 25

What is the course of the middle meningeal artery?

Answer 25

passes between the two roots of the auriculotemporal nerve (a branch of V3) and ascends to and through the foramen spinosum to enter the cranial cavity where it is a major supplier of the dura mater.

Question 26

What is the course of the inferior alveolar artery?

Answer 26

travels inferiorly to enter the mandibular foramen where it supplies the mandibular teeth and soft tissues. It exits the mandible anteriorly 38 through the mental foramen as the mental artery.

Question 27

The mandibular nerve has 5 sensory nerve branches: What are the following sensory nerves?

Answer 27

* Inferior alveolar * Lingual * Auriculotemporal * Meningeal * Buccal

Question 28

``` • Inferior alveolar • Lingual • Auriculotemporal • Meningeal • Buccal What do they innervate? What is their course? What other nerves accompany them? (Comprehensive, Individual next) ```

Answer 28

• Inferior alveolar - enters the mandibular foramen after giving off the motor nerve to the mylohyoid and anterior belly of the digastric muscles; sensory to the mandibular teeth and, as its terminal mental nerve, the lower lip and chin. • Lingual - general sensation to the anterior 2⁄3 of the tongue and floor of mouth. (Accompanied for part of its course by the chorda tympani nerve.) • Auriculotemporal – travels beside the parotid gland and ascends next to the superficial temporal artery to the temporal region; sensory to temporal skin, ear structures, TMJ and parotid gland. Also carries secretomotor parasympathetic postganglionic fibers from the otic ganglion to the parotid. • Meningeal – travels with the middle meningeal artery through the foramen spinosum to supply the dura mater of the middle cranial fossa mainly. 41 • Buccal – sensory to the skin, oral mucosa and gingiva in the cheek region. (The buccinator muscle itself is innervated by the facial nerve.)

Question 29

• Inferior alveolar What do they innervate? What is their course? What other nerves accompany them?

Answer 29

• Inferior alveolar - enters the mandibular foramen after giving off the motor nerve to the mylohyoid and anterior belly of the digastric muscles; sensory to the mandibular teeth and, as its terminal mental nerve, the lower lip and chin.

Question 30

• Lingual What do they innervate? What is their course? What other nerves accompany them?

Answer 30

Lingual - general sensation to the anterior 2⁄3 of the tongue and floor of mouth. (Accompanied for part of its course by the chorda tympani nerve.)

Question 31

• Auriculotemporal What do they innervate? What is their course? What other nerves accompany them?

Answer 31

Auriculotemporal – travels beside the parotid gland and ascends next to the superficial temporal artery to the temporal region; sensory to temporal skin, ear structures, TMJ and parotid gland. Also carries secretomotor parasympathetic postganglionic fibers from the otic ganglion to the parotid.

Question 32

• Meningeal What do they innervate? What is their course? What other nerves accompany them?

Answer 32

Meningeal – travels with the middle meningeal artery through the foramen spinosum to supply the dura mater of the middle cranial fossa mainly.

Question 33

• Buccal What do they innervate? What is their course? What other nerves accompany them?

Answer 33

Buccal – sensory to the skin, oral mucosa and gingiva in the cheek region. (The buccinator muscle itself is innervated by the facial nerve.)

Question 34

What are the 8 muscles that the mandibular nerve has motor | innervation to?

Answer 34

Temporalis Masseter Lateral and Medial pterygoid anterior belly of the digastric mylohyoid tensor veli palatini in the soft palate tensor tympani in the middle ear.

Question 35

Describe the efferent course of the parasympathetic innervation to the submandibular and sublingual glands of the mouth.

Answer 35

Preganglionic parasympathetic fibers (the black line) exit the brainstem and travel with the facial nerve before branching from the facial nerve in the facial canal as the chorda tympani then between the malleus and incus, enters the infratemporal fossa by passing through the petrotympanic fissure. The chorda tympani then “hitch-hikes a ride” on the lingual nerve and synapses in the submandibular ganglion, which “hangs off” the lingual nerve. Postganglionic secretomotor fibers (the blue dotted lines) travel to the submandibular and sublingual salivary glands as well as the multiple minor microscopic salivary glands in the inferior oral cavity.

Question 36

Describe the afferent course of the special sense taste fibers to the CNS.

Answer 36

In the opposite direction afferent special sense taste fibers from the anterior 2⁄3 of the tongue (black dotted line), originally traveling in the lingual nerve, join the chorda tympani and travel posteriorly to join CN VII back to the brainstem. These taste fibers have their pseudo- unipolar nerve cell bodies in the geniculate ganglion of CN VII.

Question 37

Describe the course of the parasympathetic innervation to the parotid gland.

Answer 37

Other preganglionic parasympathetic fibers (red line) leave the glossopharyngeal nerve (CN IX) inferior to the jugular foramen in the tympanic nerve. They enter the middle ear and ascend on the promontory in the tympanic plexus and exit it as the lesser petrosal nerve. After re-entering the cranial cavity they travel down the petrous ridge and exit through the foramen ovale to synapse in the otic ganglion. Postganglionic parasympathetic secretomotor fibers (red dotted line) “hitch-hike a ride” on the auriculotemporal nerve to the parotid gland.

Question 38

Where is the otic ganglion located?

Answer 38

The otic ganglion is located along the medial side of the mandibular nerve just inferior to the foramen ovale and near the origin of the auriculotemporal nerve.

Question 39

What is the venous drainage the infratemporal fossa?

Answer 39

The pterygoid venous plexus, which receives some blood from the ophthalmic and facial veins, drains the infratemporal fossa into the maxillary vein which joins the superficial temporal vein to form the retromandibular vein.

Question 40

What are the clinical ramifications of the pterygoid venous plexus drainage?

Answer 40

The pterygoid venous plexus also has direct valveless drainage into the cavernous sinus, so infections could spread there and lead to a cavernous sinus thrombosis, a potentially fatal situation. The danger area on the face for infections is suggested by the red triangle.