Anatomy: Temporal & Infratemporal Fossae Flashcards
Boundaries of temporal fossa
- Posterior and Superior
- Anterior
- Lateral
- Inferior
Temporal fossa boundaries that house the temporal lines
Posterior and Superior boundaries
Temporal fossa boundary that houses the frontal and zygomatic bones
Anterior boundary
Temporal fossa boundary that houses the zygomatic arch
Lateral boundary
Temporal fossa boundary that houses the infratemporal crest of the sphenoid bone (best seen when the zygomatic arch has been removed)
Inferior boundary
Contents of temporal fossa
- Temporalis muscle
- Temporalis fascia
- Deep temporal vessels and nerves (run underneath the temporalis muscle)
- Superficial temporal vessels (runs up directly in front of ear)
- Auriculotemporal nerve (runs up directly in front of ear along with superficial temporal vessels)
The “keystone” of the skull with lots of foramina and landmarks for the skull
Sphenoid Bone
What is exposed by the removal of the zygomatic arch and mandible
Infratemporal fossa
Synovial definition
Freely movable
A synovial joint; modified hinge joint
Temporomandibular joint
Articular surfaces of the tempormandibular joint
- Mandibular condyle
- Mandibular fossa
- Articular tubercle of the temporal bone
Composed of fibrocartilage; Divides the tempormandibular joint into two compartments
Articular disc
The articular disc divides the tempormandibular joints into two compartments, known as the:
- Superior compartment
- Inferior compartment
Responsible for gliding movements of protrusion and retrusion
“Push jaw forward and pull it back”
“Side to side/back and forth movements”
Superior compartment
Responsible for hinge movements of depression and elevation
“Elevate/depress mandible”
Inferior compartment
Allow the jaw to be able to move around: protrude out, retrude in, elevate/depress mandible, side to side/back and forth movements
Superior and inferior compartments of the temporomandibular joint, created by the articular disc
Peripherally attached to the joint capsule
Articular disc
Anteromedially attaches to the tendon of the lateral pterygoid
IMPORTANT TO KNOW
Articular disc
Joint or articular capsule of the TMJ attaches where?
- Superiorly to the articular tubercle
- Superiorly to the margins of the mandibular fossa
- Inferiorly to the neck of the mandible
What lines the joint capsule above and below the articular disc, but does not cover the articular disc
Synovial membrane
Ligaments of the TMJ
- Tempormandibular Ligament (lateral ligament)
- Stylomandibular Ligament (originates from the styloid process)
- Sphenomandibular Ligament (attaches at the lingula)
What sits right behind the lingula, which dentists anesthetize to numb the pt?
Inferior alveolar nerve
Muscles of mastication
- Temporalis
- Masseter
- Medial Pterygoid
- Lateral Pterygoid
Innervation of mastication muscles
Branches of V3 (Mandibular branch of the trigeminal nerve)
Insertion of Temporalis
Coronoid process and Anterior surface of the ramus of the mandible
Innervation of Temporalis
Anterior and Posterior deep temporal nerves
Actions of Temporalis
- Elevate mandible (closes mouth)
- Retrusion of mandible (Pull jaw backward)
- Right and Left lateral movements (grinding and chewing)
Origin of Masseter
Inferior border of medial surface of the maxillary process of the zygomatic bone and the zygomatic arch…..
Ha.
Ha.
“Coming from region of zygomatic arch”
Insertion of Masseter
Angle and Lateral surface of mandible
Innervation of Masseter
Masseteric nerve
Actions of Masseter
- Elevation of mandible
- Right and Left lateral movements
- Protrusion of mandible
- Retrusion of mandible
*Reversible because it can do both protrusion and retrusion movements which are in opposite directions
Origin of SUPERIOR head of Lateral Pterygoid
IMPORTANT
Infratemporal surface of greater wing of the sphenoid
Origin of INFERIOR head of Lateral Pterygoid
IMPORTANT
Lateral surface of lateral pterygoid plate
Insertion of Lateral Pterygoid
GARGOYLE!!!
- Most fibers: Pterygoid forces on anterior surface of neck of mandible
- (GARGOYLE)Some fibers from SUPERIOR head: Joint capsule and Articular disc of TMJ
Innervation of Lateral Pterygoid
Lateral pterygoid nerves
Actions of Lateral Pterygoid
IMPORTANT
- Protrusion of mandible
- **Depress mandible (helps open the mouth)
- Right and Left lateral chewing and grinding movements
Origin of DEEP head of Medial Pterygoid
Medial surface of lateral pterygoid plate
Origin of SUPERFICIAL head of Medial Pterygoid
Tuberosity of maxilla
Insertion of Medial Pterygoid
Medial surface of angle of mandible
Innervation of Medial Pterygoid
Medial Pterygoid nerve
Actions of Medial Pterygoid
- Elevation of mandible
- Protrusion of mandible
- Right and left lateral chewing and grinding movements
Muscles that assist in depressing the mandible (opening the mouth)
- Suprahyoid Muscles
- Infrahyoid Muscles
What can cause Anterior jaw/joint Dislocation
Excessive contraction of the lateral pterygoid may cause the heads of the mandible to dislocate anteriorly past the articular tubercles
What happens during anterior dislocation, and what causes it to happen?
Cause: Pt yawns really wide and dislocates their jaw
Effect: Mandible remains open, and person cannot close it
How is reduction performed for anterior jaw dislocations?
By pressing downward and backward on the last molar teeth
Why is posterior jaw dislocation uncommon?
Due to the presence of the postglenoid tubercle and the strong lateral ligament
What is more likely to occur than a posterior jaw dislocation?
Fracture of the neck of the mandible caused by falls on the chin or a direct blow to the chin
The “main show or main event”
-in Dr. Soltesz’ words
The infratemporal fossa
Communications with the infratemporal fossa
- temporal fossa (through the space b/w the zygomatic arch and the cranial wall)
- orbit (through the inferior orbital fissure)
- middle cranial fossa (through the foramen ovale and the foramen spinosum)
- pterygopalatine fossa (via the pterygomaxillary fissure)
Contents of Infratemporal fossa
- Medial and Lateral pterygoid muscles
- Mandibular division of the trigeminal nerve (V3)
- Otic ganglion
- Chorda tympani (nerve)
- Maxillary artery and its branches
- Maxillary vein and pterygoid venous plexus
Consists of 2 parts: Large sensory component and Small motor component
Mandibular division of Trigeminal Nerve (V3)
V3 exits from:
Middle cranial fossa via foramen ovale; Enters infratemporal fossa; Divides into anterior and posterior divisions
Where do branches of V3 come from?
- Main trunk
- Anterior and Posterior divisions
–And then those ant and post divisions will have their own branches
Branches of V3 from Main Trunk (before it splits into the anterior and posterior divisions)
- Nerve to the medial pterygoid
- Meningeal branch (nervous spinosus/recurrent branch of V3 to dura mater)
What does the branch from V3 to the medial pterygoid supply?
- Medial pterygoid
- Gives small branches to:
- -tensor tympani
- -tensor veli palatine
What does the meningeal branch of V3 do?
- Enters middle cranial fossa via foramen spinosum (similar to middle meningeal artery)
- Innervates dura mater of middle cranial fossa
