week nine - trigeminal + facial nerve

Question 1

describe the trigeminal nerve
sensory or motor:
cranial exit:
distribution:
func:

Answer 1

sensory or motor: both

cranial exit: sup.orb.fis , foramen rotundum and foramen ovale of sphenoid bone

distribution: 3 major divs
1. opthalmic
2. max.
3. mand.

func:
sensory to face + structures of orbit, nasal + oral cav
motor - MOM, mylohyoid and ant belly of digastric

Question 2

describe the opthalmic div of the trigeminal n.

Answer 2

• SMALLEST of the divs.
• sensory
• exits via SOF of sphenoid
• afferents to lat. upper eyelid, conjunctiva and lacrimal gland, parasym nerves to lacrimal gland

Question 3

describe the max. div of the trigeminal n.

Answer 3

• sensory
• exits via foramen rotundum
• afferent for maxilla, overlying skin, max. sinuses, nasal cav., palate, nasopharynx, part of dura mater
• key nerve for oral cav. inn. [max teethm buccal/palatal, gingiva, hard/soft tx upper lip]

Question 4

describe the mand. div. of the trigeminal n.

Answer 4

largest of three divs
passes through foramen ovale
sensory and motor
- afferent - caries info for mandible and overlying skin, tongue, FOM, part of dura mater
- efferent to MOM, mylohyoid, ant belly of diagastric, tensor tympani + tensory palatini musc
- key nerve for oral cav inn. [mand. teeth, buccal/lingual gingiva, FOM, ant 2/3 of tongue and lower lip]

Question 5

list the THREE types of superior alveolar nerves and distinguish between them

Answer 5

1. anterior superior alveolar
   - sensory from ant. teeth [max cen.incis. laterals, canines] + labial gingiva
   - originates from apical foramina of ant. teeth
   - receives interdental branches from surrounding periodontium = dental plexus
   - asc within ant. wall of max. sinus&raquo_space; unites w terminal branches of IO n.&raquo_space; IO n. in floor of orbit
2. middle superior alveolar
   - sensory from premolars + MB roots of max first molars + assoc periodontium + buccal gingiva
   - originates from apical foramina of ^ teeth
   - receives interdental branches from surrounding periodontium = dental plexus
   - asc within lat. wall of max. sinus to reach floor of orbit» unites w/ IO n. in floor of orbit
   - not present in all pts –> when absent = inn. from PSA
3. posterior superior alveolar
   - sensory from max first molars [except MB roots] + assoc periodontium + buccal gingiva
   - originates from apical foramina of max molars
   - receives interdental branches from surrounding periodontium = dental plexus
   - asc along post. wall of max.&raquo_space; exits bone through poramina on post. wall of max and max. tuberosity
   - passes through pterygomaxillary fissure&raquo_space; unites w max. div. of trigeminal n.

Question 6

list and describe the THREE palatine nerves

Answer 6

1. greater palatine nerve
   - sensory from palatal mucoca + gingiva + **post. 2/3 of hard palate **
   - travels posteriorly&raquo_space; greater palatine formane&raquo_space; pterygopalatine canal along w greater palatine blood vessels → pterygopalatine fossa
   - unites w/ lesser palatine nerve → forms palatine nerve
2. lesser palatine nerve
   - sensory from palatal mucosa of** soft palate and palatine tonsils **
   - travels anteriorly&raquo_space; lesser palatine foramen&raquo_space; unites w greater palatine n.&raquo_space; pterygopalatine canal –> pterygopalatine fossa
3. nasopalatine nerve
   - sensory from palatal mucosa and gingiva of ant 1/3 of hard palate
   - R/L NP n. enter incisive foramen&raquo_space; incisive canal&raquo_space; pterygopalatine fossa

Question 7

describe the long buccal n.

Answer 7

sensory for skin of cheek, buccal mucous mem. + buccal gingiva of mand. post. teeth
- travels in post. cheek, deep to masseter musc.

Question 8

describe the inferior alveolar nerve [IAV]

Answer 8

• formed from memtal + incisive nerves

mental nerve
- sensory for skin of chin, lower lip, labial mucosa of mand. premolars and ant. teeth
- enters mental foramen&raquo_space; unites w incivisve n.&raquo_space;> IAV

incisive nerve
- originates from dental branches of ant. and premolars apical foramina
- receives interdental branches from surrounding periodontium, forming dental plexus

IAV
- sensory info for ALL mand teeth + buccal gingiva ant. to molars
- exits mand through mand. foramen + joined by mylohyoid nerve
- travels post. w. inf.alv.v.+a., joined by interdental and interradicular branches from mand post teeth = plexus

Question 9

describe the lingual nerve

Answer 9

• sensory to ant 2/3 of tongue, FOM, lingual gingiva
• formed from sensory branches from body of tongue

Question 10

descibe the facial nerve

Answer 10

emerges from brain and enters internal acoustic meatus of temporal bone
exits: stylohyoid mastoid
func
motor: musc of fac expression, middle ear, stylohyoid musc, post belly digastric
parasym: lacrimal, subling,submand salivary glands
special sensory: taste of ant 2/3 tongue

passes to parotid gland and divs - 5 motor branches that supp musc of fac expression

greater petrosal nerve
for parasym innervation of lacrimal gland, minor salivary glands of hard/soft palate, nasal cav,

chorda tympani
submand + sibling salivary glands + special sensory fibres for **taste sensation ant ⅔ of tongue **