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neuro 2019 Exam 3 > Infratemporal Fossa > Flashcards

Infratemporal Fossa Flashcards

1
Q

Temporal Fossa

A

Lateral area of skull overlying squamous portions of frontal, parietal, temporal, and sphenoid bones. This region is continuous inferiorly with the infratemporal fossa.

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2
Q

boundaries of the temporal foss

A
  1. Anterior/superior/posterior – superior temporal line (zygomatic, frontal, parietal, temporal bones)
  2. Inferior (lateral) – zygomatic arch
  3. Inferior (medial) – infratemporal crest of temporal and sphenoid bones
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3
Q

Contents of the temporal fossa

A

upper portion of temporalis muscle and a dense temporalis fascia.

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4
Q

Infratemporal fossa

A

A. Deep region of head lying inferior and deep (inferiomedial) to temporal region.

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5
Q

boundaries of the infratemporal fossa

A
  1. Lateral – ramus of mandible
  2. Superior (lateral) – zygomatic arch
  3. Superior (medial) – infratemporal crest of temporal and sphenoid bones
  4. Medial – lateral pterygoid plate of sphenoid and pharynx
  5. Anterior – maxilla
  6. Posterior – imaginary line connecting posterior border of ramus of mandible and styloid process of temporal bone
  7. Inferior – continuous with submandibular region
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6
Q

General contents of the infratemporal fossa

A
  1. Lower portion of temporalis muscle
  2. Medial pterygoid
  3. Lateral pterygoid
  4. Maxillary artery (1st and 2nd portion)
  5. Pterygoid plexus of veins
  6. Mandibular division of CN V (V3)
  7. Otic ganglion
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7
Q

Temporomandibular joint

A

A. Articulation between:

  1. Mandible - condyle
  2. Temporal bone – mandibular fossa and articular tubercle

B. Operates during chewing; while opening mouth, the condyle of the mandible slides anteriorly against the posterior surface of the articular tubercle.

C. Contains a dense connective tissue articular disc which separates the joint into two separate synovial lined cavities.

D. Joint capsule is loose above disc and tight below disc.

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8
Q

Ligaments of the TMJ

A

E. Ligaments

  1. Lateral ligament of TMJ
    a. Thickening of joint capsule
    b. Helps to prevent posterior dislocation of mandible
  2. Stylomandibular ligament
    a. Thickening of parotid fascia
    b. Extends from styloid process to angle of mandible
    c. Not a very strong ligament
  3. Sphenomandibular ligament
    a. Extends from spine of sphenoid to lingula of mandible
    b. Strong ligament; provides most of passive support for TMJ
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9
Q

TMJ– synovial joint

A
  1. Upper portion (between temporal bone and disc)
    a. Gliding movements
    b. Allows for protrusion/retrusion and elevation/depression of mandible
  2. Lower portion (between disc and mandible)
    a. Pivot-type movements
    b. Allows for side-to-side movements during chewing.
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10
Q

CLINICAL CORRELATION – Dislocation of the TMJ

A
  1. Mandibular condyle slides too far anteriorly (anterior to the articular tubercle) and results in inability to close the jaw.
  2. Mandible must be pushed inferiorly and then posteriorly to correct the dislocation.
  3. Dislocation may damage the auriculotemporal nerve.
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11
Q

CLINICAL CORRELATION – The TMJ can develop arthritis

A

leading to degeneration of the cartilage and bones of the joint. This can sometimes be painful; and also cause clicking (crepitus) or popping while opening.

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12
Q

Muscles of Mastication and their shared features

A

Temporalis
Masseter
Medial pterigoid
Lateral pterygoid

  1. Derived embryologically from the 1st pharyngeal arch
  2. Innervated by V3
  3. Function – mastication
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13
Q

Temporalis

A
  1. Origin – temporal lines and deep temporal fascia / infratemporal crest
  2. Insertion – coronoid process and anterior surface of ramus of mandible
  3. Function – elevates (closes) and retracts jaw
  4. Innervation – V3 via anterior and posterior deep temporal nn.
  5. Special feature – temporobuccinator band
    a. Dense fascial band that spans from temporalis tendon to buccinator muscle.
    b. Function – pull buccinator muscle away from teeth.
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14
Q

Masseter

A
  1. Origin – zygomatic arch (maxilla and zygomatic bone)
  2. Insertion – external surface of ramus of mandible
  3. Function – elevates (closes) mandible; assists with protrusion
  4. Innervation – V3 via masseteric branches
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15
Q

Medial pterygoid

A
  1. Origin – medial surface of lateral pterygoid plate (deep head); tuberosity of maxilla (superficial head)
  2. Insertion – internal surface of ramus of mandible
  3. Function – elevates (closes) mandible and assists with protrusion and pivot movements of mandible.
  4. Innervation – V3 via medial pterygoid branch
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16
Q

Lateral Pterygoid

A
  1. Origin – lateral surface of lateral pterygoid plate (deep head); infratemporal crest of sphenoid bone (superficial head)
  2. Insertion – neck of mandibular condyle (deep portion); articular disc (superficial; sphenomeniscal portion)
  3. Function – protrusion of mandible; acting unilateral, moves jaw towards contralateral side to produce pivot movements of chewing (side-to-side movement of jaw).
  4. Innervation – V3 via lateral pterygoid branch
17
Q

Maxillary artery

A

A. One of two terminal branches of external carotid artery (superficial temporal artery is the other terminal branch).

B. Courses posterior to neck of mandible (between it and the sphenomandibular ligament) to enter the infratemporal fossa.

C. 3 portions – mandibular, pterygoid, and pterygopalatine

18
Q

Mandibular portion of maxillary artery

A
  1. Courses deep to neck of mandible
  2. Branches
    a. Deep auricular a. – external acoustic meatus, outer tympanic membrane, and TMJ.
    b. Anterior tympanic a. – inner tympanic membrane (courses through petrotympanic fissure to reach middle ear).
    c. Middle meningeal a. enters middle cranial fossa via foramen spinosum to supply dura and skull.
    d. Accessory meningeal a. enters middle cranial fossa via foramen ovale to supply dura and skull.
    e. Inferior alveolar a. enters mandibular foramen to supply mandible, mandibular teeth, and chin (via mental branch); also gives rise to the mylohyoid artery prior to entering mandibular foramen.
19
Q

Pterygoid portion of maxillary artery

A
  1. Courses through infratemporal region; either superficial or deep (50/50) to the lateral pterygoid muscle.
  2. Branches
    a. Masseteric branches
    b. Anterior and posterior deep temporal
    c. Medial pterygoid branches
    d. Lateral pterygoid branches
    e. Buccal artery supplies cheek.
20
Q

Pterygopalatine portion of maxillary artery

A
  1. Courses through pterygomaxillary fissure to enter pterygopalatine fossa.
  2. Branches
    a. Posterior superior alveolar a.
    b. Infraorbital a.
    c. Pharyngeal a.
    d. Artery of pterygoid canal
    e. Descending palatine a.
    f. Sphenopalatine a.
21
Q

Pterygoid plexus of veins

A

A. Large venous plexus investing external and internal surface of lateral pterygoid muscle.

B. Receives blood from (communicates with):

  1. Infratemporal fossa and nasal cavity via venae comitantes of maxillary artery
  2. Face via deep facial vein and ophthalmic veins
  3. Cavernous sinus via emissary veins
  4. Pharynx via pharyngeal veins

C. Coalesces to form maxillary vein which then exits the infratemporal fossa traveling with the maxillary artery.

22
Q

Mandibular Nerve (V3)

A

A. General features

  1. Exits middle cranial fossa via foramin ovale to enter infratemporal fossa.
  2. Components
    a. GSA to lower portion of face; including chin, lower check, and temporal region; mandibular teeth and gingivae; auricle and external acoustic meatus; floor of oral cavity; 2/3rds of tongue; and dura of middle cranial fossa
  3. SVE fibers to all muscles of 1st pharyngeal arch origin
    a. Muscles of mastication
    b. Tensor tympani
    c. Tensor veli palatini
    d. Anterior belly of digastric
    e. Mylohyoid
  4. Distributes GVE-P fibers from the CN VII and CN IX to the salivary glands.
  5. Distributes SVA fibers from the CN VII to the anterior 2/3rds of the tongue.
23
Q

Sensory branches (GSA) of Mandibular Nerve

A

Meningeal br
Buccal n.
Lingual n.
Auriculotemporal n.

24
Q

Meningeal br of Mandibular nerve

A

a. Re-enters middle cranial fossa via foramen spinosum

b. Supplies dura of middle cranial fossa

25
Q

Buccal n

A

branch of mandibular n.

a. Exits the infratemporal region by passing between the two heads of the lateral pterygoid muscle
b. Pierces mucosa of cheek to supply cheek (internal and external), gingivae

26
Q

Lingual n.

A

a. Exits the infratemporal region by passing between the medial and lateral pterygoid muscles
b. Travels to oral cavity
c. Supplies the anterior 2/3rds of the tongue, floor of oral cavity, and mandibular gingivae with sensory innervation.
d. NOTE: Chorda tympani nerve (CN VII) joins the lingual nerve in the infratemporal fossa to distribute taste (SVA) to the anterior 2/3rds of the tongue and GVE-P fibers to the submandibular and sublingual glands.

27
Q

Auriculotemporal n.

A

a. Arises from two roots which surround the middle meningeal artery.
b. Exits infratemporal fossa posteriorly by passing deep to neck of mandible.
c. Provides GSA to the TMJ, temporal region, auricle, external acoustic meatus, and external tympanic membrane.
d. NOTE: this nerve distributes GVE-P fibers to the parotid gland.

28
Q

C. Motor Branches (SVE) of Mandibular n.

A
  1. Medial pterygoid n
  2. Nerve to tensor tympani
  3. Nerve to tensor veli palatini
  4. Lateral pterygoid nn
  5. Masseteric nn
  6. Anterior and posterior deep temporal nn.
29
Q

Mixed branch (GSA and SVE) of mandibular nerve

A
  1. Inferior alveolar n. (GSA and SVE)
    a. Enters to the mandibular foramen to supply the mandibular teeth.
    b. Branches
  2. Mental n. –exits the mental foramen to supply the chin
  3. Mylohyoid n. (SVE) – supplies mylohyoid, anterior belly of digastric
30
Q

E. CLINICAL CORRELATION: Nerve Blocks of mandibular n.

A
  1. Mandibular nerve block – needle passed through mandibular notch to inject anesthetic around main trunk of mandibular nerve.
  2. Inferior alveolar nerve block
    a. Used primarily by dentists to anesthetize mandibular teeth.
    b. Anesthetic is injected near the entrance of mandibular foramen.
31
Q

Autonomics (GVE-P) DISTRIBUTED by the Mandibular nerve– Parotid

A
  1. Otic ganglion
    a. Located in infratemporal fossa
    b. Suspended from V3; lies deep (medial) to the main trunk of V3.
    c. Contains the cell bodies of postganglionic parasympathetic fibers.
    d. Provides innervation for the parotid gland
  2. Parasympathetic
    a. Preganglionic
    1 Location of cell bodies – salivatory nucleus within brainstem
    2 Preganglionic fibers travel with CN IX
    3 CN IX exits at jugular foramen and gives a tympanic branch.
    4 Tympanic nerve enters middle ear via the tympanic canaliculus.
    5 Travels through middle ear and reforms as lesser petrosal nerve.
    6 Lesser petrosal nerve exits middle ear via hiatus for the lesser petrosal nerve; nerve is now in middle cranial fossa and exits via foramen ovale to infratemporal fossa.
    7 Lesser petrosal is in infratemporal fossa and synapses in otic ganglion.
    b. Postganglionic (distribute with V3)
  3. Location of cell bodies – otic ganglion
  4. Postganglionic fibers travel with the auriculotemporal n of V3.
    c. Function: secretomotor; stimulate salivation
32
Q

Autonomics (GVE-P) DISTRIBUTED by the Mandibular nerve– sublingual and submandibular glands

A
  1. Parasympathetic
    a. Preganglionic
  2. Location of cell bodies – salivatory nucleus within brainstem
  3. Preganglionic fibers travel with the facial nerve (CN VII).
  4. CN VII courses along the posterior wall of the middle ear and gives rise to the chorda tympani n. which exits the middle ear through the petrotympanic fissure to enter the infratemporal fossa.
  5. Here, chorda tympani joins the lingual nerve.
  6. Chorda tympani portion of lingual nerve synapses in the submandibular ganglion.
    b. Postganglionic
  7. Location of cell bodies – submandibular ganglion
  8. Postganglionic fibers travel with the lingual branch of V3.
    c. Function: secretomotor; stimulate salivation

neuro 2019 Exam 3 (17 decks)

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