What type of joint is the TMJ?
modified hinge
Label
Anteriorly is articular tubercle
posteriorly is post glenoid tubercle
label
anteriorly is articular aminence
middle is articular tubercle
posteriorly is post glenoid tubercle
Borders of mandibular fossa
Lateral: zygomatic process of temporal bone
Medial: spine of sphenoid bone
Anterior: articular eminence
Posterior: squamotympanic and petrotypanic fissures
what passes through petrotympanic fissure?
chorda tympani
What’s more medial: squamotympanic fissure or petrotympanic fissure?
pertrotympanic fissure is the more medial half
How are the condyles of the mandible formed?
intramembranous ossification
What attaches to external oblique line?
depressor anguli oris
What is found on each side (laterally) of the mental spine of the interior mandible?
digastric fossae
What attaches to the digastric fossae?
origin of the anterior belly of the digastric
What attaches to the mental spine?
genioglossus muscle attaches to superior aspect of mental spine
geniohyoid attaches to lower aspect
What passes through mandibular canal?
inferior alveolar nerve and artery
what passes through mental foramen?
cutaneous branches of inferior alveolar nerve and artery
What attaches to the lingula?
sphenomandibular ligament
what runs along mylohyoid sulcus/groove and where is it located?
runs downward and forward from inferior border of mandibular foramen
nerve to mylohyoid muscle runs along it
What’s the shape of the articualr disc?
biconcave
Where are superior and inferior lamellae found?
inner periphery of articulator capsule
primary composition of superior and inferior lamellae
Superior is ELASTIC
inferior is COLLAGEN
two regions of joint capsule of TMJ
capsular ligament and lateral/temporomandibular ligament
what does the capsular ligament prevent?
excessive lateral movement and posterior dislocation
what does lateral/temporomandibular ligament prevent?
excessive lateral movement and posterior dislocation
attachments of stylomandibular ligament
styloid process to angle of mandible
function of stylomandibular ligament
limits protrusion
sphenomandibular attachments
from spine of sphenoid to lingula of mandible
function of sphenomandibular ligament
supports weight of mandible
prevents excessive lateral movement of mandible
fulcrum of elevation and depression of the mandible
approx. at mandiblar foramen
Locations of hinge movement and gliding at TMJ
hinge at lower joint compartment
gliding/translation at upper joint compartment
attachments of temporalis muscle
temporal fossa
tip of coronoid process, ramus of mandible
action of temporalis muscle
elevation, retrusion of mandible (bilaterally)
also holds resting position of mandible
innervation of temporalis muscle
deep temporal branches
attachments of masseter muscle
outer and inner surfaces of zygomatic bone and arch
angle and lateral surface of ramus of mandible
action of masseter muscle
bilateral elevation and protrusion of the mandible
innervation of masseter muscle
masseteric nerve
attachments of lateral pterygoid muscle
Sup head: greater wing of sphenoid
Inf head: lateral pterygoid plate
both: capsule, disc, condyle
action of lateral pterygoid muscle
bilateral mandibular depression (only muscle of mastication that does this), protracts mandible
innervation of lateral pterygoid muscle
lateral pterygoid nerve
attachments of medial pterygoid muscle
lateral pterygoid plate, tuberoisity of maxilla
medial ramus of mandible, inferior to mandibular foramen
action of medial pterygoid muscle
bilateral elevation, protrusion
innervation of medial pterygoid muscle
medial pterygoid nerve
what gives sensory information to TMJ?
auriculotemporal nerve (also small anterior portion by masseteric branches of V3)
pain from posterior and posterolateral regions of capsule
retrodiscal inferior lamella contains proprioceptive mechanoreceptors for condyle movement
what gives blood supply to TMJ?
articular branches from superficial temporal artery
also arterial twigs from muscular branches of maxillary artery for anterior aspect
