4.4 mastication and temporal fossa

chewing forms..for…

bolus for deglutition (swallowing)

mandible articulation

head (mandibular chondyle) articulates with temporal bone

temporomandibular joint

jaw joint, has articular disc between the bones

types of jaw movements

protrusion, protraction, retrusion, retraction, elevation, depression, can move laterally during chewing

external/superficial to mandible muscles of mastication

masseter, temporalis

internal/deep to mandible muscles of mastication

lateral pterygoid and medial pterygoid muscle

muscle of mastication innervation and blood supply

mandibular nerve, maxillary artery (2nd part)

masseter function

elevate and protract mandible

temporalis function

elevate and retract mandible

sphenoid bone special feature

lateral and medial pterygoid plates

lateral pterygoid muscle function

protrude and depressed mandible, side to side movement of it

medial pterygoid function

elevates mandible, helps lateral pterygoids with lateral movement

ligaments

lateral, stylomandibular, joint capsule, sphenomandibular

hinge of jaw

wide gap: unhinged, articular disc slides anterior to mandibular fossa → articulates against articular tubercle

dislocation of TMJ explanation and help

excessive anterior translation, treat: reduction

temporal fossa

temporalis attaches

infratemporal fossa contents

medial + lateral pterygoids, pterygoid venous plexus, maxillary artery, maxillary nerve, mandibular nerve

pterygoid plexus location and communication

mass found on and near pterygoids, communicated with cavernous sinus inside cranium

external carotid artery branches

superficial temporal and maxillary artery

maxillary artery parts and supply

1st, 2nd (supplies jaw), 3rd

maxillary artery branches

inferior alveolar, middle meningeal, foramen spinosum, spenopalatine

trigeminal nerve skull exit

v1- superior orbital fissure

v2- foramen rotundum

v3- foramen ovale

maxillary nerve

infraorbital nerve exits infraorbital foramen

spheno/pterygopalatine ganglione

superior alveolar nerve = upper tooth sockets

v3 branch

auriculotemporal nerve

main trunk of mandibular

meningeal branch

nerve to medial pterygoid

meningeal branch

sensory, middle meningeal artery, sensation from dura inside middle cranial fossa

nerve to medial pterygoid

-motor, tensor typani, tensor veli palatini

anterior division of mandibular nerve

nerve to masseter

deep temporal

nerve to lateral pterygoid

buccal

nerve to masseter

sensory to TMJ and motor to muscle

deep temporal

motor to temporalis

nerve to lateral pterygoid

motor

buccal

sensory to skin and mucous membrane cheek and gingiva

posterior mandibular nerve branches

auriculotemporal

lingual

inferior alveolar

auriculotemporal

sensory and carries parasympathetic from CNIX

lingual

sensory, carries special sensory (taste) from CNVII, carries parasymptathetic from CNVII

inferior alveolar nerve

sensory and motor

parasympathetic cranial nerves innervating head and necck

CN III - pupil constriction and lens accommodation

CNVII- lacrimal, sublingual, submandibular glands

CNIX - parotid gland

CNX parasympathetics

no head and neck effectors, just chest and abdomen

cranial nerve goes to all regions but doesn’t have parasympathetic neurons of its own

CN V - III, VII, and IX hitchhike along CNV branches

cranial nerve parasympathetic neurons synapse site

preganglionic and postganglionic synapse with each other at parasympathetic ganglia near effectors

lingual nerve hitchhiking

V3: general sensation to anterior 2/3 of tongue

chorda tympani (CNVII): joins to provide taste to ant 2/3 of tongue and parasympathetic to small salivary

auriculotemporal nerve

v3: general sensation of temple and ear

glossopharyngeal nerve: joints to provide parasympathetic to parotid gland

sympathetic inputs to small salivary (sublingual + submandibular)

superior cervical ganglion (most superior part) → vasoconstriction (decrease blood vessels diameter to glands→ decrease activity→ decrease saliva)

parasympathetic inputs to small salivary (sublingual + submandibular)

pregangionic neurons comes from pons nuclei of facia nerve

chorda typani facial nerve parasympathetic fibers hitchhike onto lingual nerve

• preganglionic parasympathetic fibers synapse with postganglionic parasympathetic neurons in submandibular region

postganglionic parasympathetic neurons distribute to small salivary glands → stimulate secretion

sympathetic innervation of parotid gland

superior cervical ganglion (most superior part of sympathetic trunk) → vasoconstriction (decrease blood vessels diameter to glands→ decrease activity→ decrease saliva)

parasympathetic innervation of parotid gland

preganglionic parasympathetic lead medulla through glossopharyngeal nerve → synapse at otic ganglion inferior to foramen ovale

postganglionic parasympathetic neurons reach parotid by hitchhiking on auriculotemporal nerve

branstem origins of cranial nerves

midbrain : III, IV

pons : V, VI, VII, VIII

medulla : IX, X, XI, XII

cribriform plate exit

olfactory nerve

optic canal exit

optic nerve

superior orbital fissure exits

oculomotor, trochlear, opthalmic, abducens

foramen rotundum

maxillary nerve

foramen ovale exit

mandibular nerve

internal acoustic meatus exit

facial nerve, vestibulocochlear

jugular foramen exit

glossopharyngeal, vagus, accessory

hypoglossal canal exit

hypoglossal nerve