Anatomy - Temporal and infratemporal fossa

Question 1

Boundaries of the temporal fossa

Answer 1

Superior: temporal lines (superior and inferior)

Anterior: frontal and zygomatic bones

Inferior: continuous w/ infratemporal fossa

lateral: zygomatic arch

Question 2

why is the pterion clinically important?

Answer 2

the anterior branches of the middle meningeal artery lie deep to it; if you fracture it you will kill this artery and get an epidural hematoma

Question 3

what are the contents of the temporal fossa?

Answer 3

1. temporalis muscle (muscle of mastication)
2. deep temporal VAN

Question 4

which bones make up the zygomatic arch?

Answer 4

1. the temporal process of the zygomatic bone
2. the zygomatic process of the temporal bone

Question 5

what attaches to the superior temporal line?

Answer 5

the temporal fascia

Question 6

what attaches to the inferior temporal line (and temporal fossa)?

Answer 6

the temporalis muscle

Question 7

what are the boundaries of the infratemporal fossa?

Answer 7

1. lateral - ramus of mandible
2. medial - lateral pterygoid plate
3. anterior - maxilla
4. posterior - tympanic plate, mastoid and styloid processes
5. superior - inferior surface of the greater wing of the sphenoid
6. inferior - where medial pterygoid attaches to angle of mandible

Question 8

what are the contents of the infratemporal fossa?

Answer 8

1. branches of mandibullar division of trigeminal nerve (V3)
2. branches of maxillary artery (external carotid; terminal branch) and the retromandibular artery
3. pterygoid plexus of veins
4. otic ganglion
5. muscles: lateral and medial ptergoid muscles + inferior part of the temporalis muscle

Question 9

which muscle attaches to the ptergoid fovea of the condylar process of the mandible?

Answer 9

lateral ptergoid muscle

Question 10

where on the mandible does the medial ptergoid attach?

Answer 10

on the medial surface of the ramus

Question 11

where on the mandible does the masseter muscle attach?

what is its proximal attachment?

what nerve supplies the masseter muscle

Answer 11

distal attachment: the angle and the lateral surface of the ramus of the mandible

proximal attachment: inferior border of zygomatic bone

nerve supply: masseteric branch of V3

Question 12

what attaches to the mylohyoid line on the medial surface of the mandible?

Answer 12

the mylohyoid muscle

Question 13

what takes attachment from the lingula?

Answer 13

the sphenomandibular ligament

Question 14

where does the temporalis muscle attach proximally? distally?

which nerve supplies the temporalis muscle?

Answer 14

proximal attachment = floor of temporal fossa

distal attachment = tip and medial

innervation = deep temporal branches of V3

Question 15

what is the proximal attachment for the lateral ptergoid muscle?

what is its distal attachment? (superior/inferior heads)

what nerve supplies this muscle?

Answer 15

proximal attachments: infratemporal surface and crest of the greater wing of the sphenoid + lateral surface of the lataer ptergoid plate

distal attachments (inferior head) - ptergoid fovea

distal attachments (superior head) - joint capsule and articular disc of TMJ

nerve supply - V3

Question 16

medial ptergoid:

what are the proximal attachments?

what are the distal attachments?

what is its nerve supply?

Answer 16

proximal attachments: medial surface of lateral ptergoid plate + pyramidal process of palatine bone (situated at the back part of the nasal cavity between the maxilla and the pterygoid process of the sphenoid) + tuberosity of the maxilla

distal attachments: medial surface of the ramus of hte mandible, near the angle

nerve supply: V3

Question 17

how does the ptergoid plexus anastomose w/ the facial vein?

Answer 17

via the deep facial vein

Question 18

how does the ptergoid plexus anastomose w/ the cavernous sinus?

Answer 18

via emissary veins

Question 19

the chorda tymapani nerve is a branch of which cranial nerve?

which nerve does the chorda tympani join in the infratemporal fossa?

Answer 19

• the chorda tympani is a branch of the facial nerve (CN VII); it branches when CN VII is in the facial canal
• chorda tympani crosses the tympanic cavity medial to the handle of the malleus
• it joins the LINGUAL NERVE (from CN V) carrying tase fibers from the anterior two thirds of the tongue

Question 20

where would you inject anesthetic agent if you wanted to do a mandibullar nerve block?

Answer 20

at the foramen ovale of the skull

Question 21

where would you inject anesthetic if you wanted to bock the inferior alveolar nerve?

Answer 21

in the mandibular foramen

Question 22

the auricotemporal nerve has a relationship with which branch of the maxillary artery?

Answer 22

it is encircled by the middle meningeal artery, which is a branch of the maxillary artery

Question 23

what are the two terminal branches of the external carotid artery?

Answer 23

maxillary artery and superficial temporal artery

Question 24

the chorda tympani carries taste fibers from the anterior two thirds of the tongue; what other fibers does it carry?

Answer 24

it carries presynaptic parasympathetic secretomotor nerve fibers (for the submandibular and sublingual glands)

don’t forget that the chorda tympani joins the lingual nerve in the infratemporal fossa

Question 25

V2 is the maxillary division of trigeminal nerve. through which foramen does this nerve exit the skull? through where does this nerve exit the face? what is it called once it exits?

Answer 25

* the maxillary nerve (V2) exits the skull via foramen rotundum * it exits the face via the infraorbital foramen * it is called the infraorbital nerve once it is in the face

Question 26

how does the mandibular nerve (V3) exit the skull? once it exits, it splits into an anterior and posterio trunk. which trunk is smaller/bigger? what are the branches of these trunks?

Answer 26

* the mandibular nerve exits the skull via the foramen ovale * the anterior trunk is the smaller of the two trunks. its branches are: * long buccal nerve (sensory fiber to mucosa oof cheeks) * deep temporal nerves (to temporalis muscle) * masseteric nerve (to masseter) * ptergoid nerves (to medial/laterl ptergoids) * the posterior trunk is larger. its branches are: * auricotemporal nerve * lingual nerve * inferior alveolar nerve * nerve to mylohyoid

Question 27

what does the auricotemporal nerve supply?

Answer 27

* it supplies sensory fibers to the auricule and temporal regions * it supplies articular fibers to TMJ * it supplies parasympathetic seretomotor fibers to parotid gland \*Secretomotor refers to the capacity of a structure (often a nerve) to induce a gland to secrete a substance (usually mucus or serous).

Question 28

the nerve to mylohyoid supplies the mylohyoid muscle plus one other muscle. what is the other muscle?

Answer 28

the anterior belly of the digastric

Question 29

where is the otic ganglion located?

Answer 29

the otic ganglion (a parasympathetic ganglion) is located: * within the infratemporal fossa * inferior to the foramen ovale * medial to the mandibular division of V3 * posterior to the pterygoid muscle

Question 30

the otic ganglion is a parasympathetic ganglion. where do the fibers that synapse on it arise from? how are these fibers carried to the ganglion?

Answer 30

* preganglionic fibers arise from inferior salivary nucleus of the medulla * fibers are carried via the lesser petrosal nerve (arises from tympanic plexus of CN IX - glossopharyngeal - exits via foramen ovale)

Question 31

the otic ganglion is a parasympathetic ganlgion. it contains the cell bodies of post-ganglionic cells. the fibers of these cells are carried to the parotid gland via which nerve?

Answer 31

post-ganglionic fibers are carried to the parotid gland via the auricotemporal never (branch of V3) these fibers have secretomotor functions

Question 32

sympathetic fibers pass through the otic ganglion but don't synapse there. * why? * where do these fibers come from? * are they presynpatic or post synaptic? * where do they go?

Answer 32

* sympathetic fibers synapse in sympathetic ganglion, so they would not synapse in the otic ganglion, which is a parasympathetic ganglion * these fibers are derived from the superior cervical ganglion (a sympathetic ganglion) * they are post-synaptic fibers * they are going to the blood vessels of the parotid gland (remember that blood vessels are under sympathetic control only)

Question 33

the superior and inferior compartmnet of the TMJ are responsible for different actions. * what are they? * what separates the two compartments?

Answer 33

* the superior compartment is responsible for gliding movements of protrusion and retrusion * the inferior compartment is responsible for hinge movements of depression and elevation * the articular disc divides the two compartments

Question 34

the TMJ is a modified hindge type of **synovial joint** what is the intrinsic ligament of the joint? what are the extrinsic ligaments of the joint?

Answer 34

* intrinsic ligament - lateral ligament (thickening of joint capsule) * extrinsic ligament - sphenomandibular ligament (spine of sphenoid to lingula) * extrinsic ligament - stylomandibular ligament (thickening of fibrous capsule of parotid gland; extends from styloid process to angle of mandible)

Question 35

what is the most common dislocation of TMJ? why?

Answer 35

* anterior dislocation is most common * this is b/c postglenoid tubercle and lateral ligament provide stronger support posteriorly * anterior dislocation occurs when the heads of condyles of mandible pass anterior to the articular tubercles

Question 36

which muscles are responsible for elevation of the TMJ? which muscles are responsible for depression? which muscles are responsible for protrusion? which muscles are responsible for retrusion? which muscles control lateral movement?

Answer 36

1. elevation = temporalis, masseter, medial pterygoid 2. depression = lateral pterygoid, suprahyoids, infrahyoids 3. protrusion = pterygoids, masseter 4. retrusion = temporalis, masseter 5. latearl movements = temporalis (of same side), pterygoids (of opposite side), masseter

Question 37

what are the two nerevs associated with TMJ?

Answer 37

1. facial nerve - overlies the joint 2. articular branches of auricotemporal nerve (branch of V3) - enters hte posterior part of joint