Temporomandibular Joint Flashcards
TMJ consists of what
Mandible bone suspended from the temporal bone via ligaments and muscles
What type of joint is the TMJ
True Synovial joint
TMJ is formed by what
Condyle of the mandible and mandibular fossa of the temporal bone
The temporal and mandibular bone is separated by what
A meniscus (articular disc) which divides the joint into two cavities which are:
Upper joint cavity (superior joint space)
Lover joint cavity (lower joint space)
What surrounds the articular surface and blends with the articular disc
Fibrous capsule
The articular disc is lined by synovial membrane except where
Disc surface
Ligaments strengthening the TMJ and their position
Temporomandibular ligament - lateral
Sphenomandibular ligament- anterior
Stylomandibular ligament- posterior
Stylomandibular gland separates what fro what
Submandibular gland from the parotid gland
Important relations of TMJ
Check slide or camera
What is the anterior boundary of TMJ
Anterior joint eminence
Lateral pterygoid muscle
Masseteric nerve and vessels
What is the posterior boundary of TMJ
External auditory meatus
Glenoid process of the parotid gland
What is the lateral boundary of TMJ
Zygomatic arch
Parotid gland
Facia
Skin
What is the medial boundary of TMJ
Styloid process
Maxillary vessels
Auriculotemporal nerve
What are the muscles of mastication?
> Temporalis (retracts the mandibles) masseter, medial pterygoid (they close the jaw)
> Lateral pterygoid (depresses and protrudes and moves the mandible from side side)
> Suprahyoid and infrahyoid muscles (they depress the mandible) .
All these muscles are innervated by V3
What muscles are responsible for forward movement (protraction) of the TMJ?
Lateral and medial pterygoid, superficial fibres of digastric muscle
What muscles are responsible for backward movement (retraction) of the TMJ?
Temporalis, deep fibres of masseter, digastric, geniohyoid muscles
Protraction and retraction of the TMJ occurs where
The superior part of the joint cavity
What muscles are responsible for elevation of the mandible
Temporalis, medial pterygoid, masseters
What muscles are responsible for depression of the mandible
Lateral pterygoid, digastric, Mylohyoid, geniohyoid, (this move t is produced by GRAVITY)
Elevation and depression movement of the mandible takes place where
Inferior compartment of the joint cavity. These movements helps in mastication and speech
Characteristics of the menisci disc
> Has synovial fluid above and below
It’s a shock absorber
it’s held in place by medial and lateral capsular ligament and retro-disc pad
Internal derangement of the menisci disc in 50% of people can cause
Anterior and medial jaw pops
Blood supply of the TMJ
Superficial temporal artery and inferior alveolar artery (both branches of ECA), middle meningeal artery
Nerve supply of TMJ
Inferior Alveolar Nerve
Auriculotemporal nerve
Masseteric nerve
Auriculotemporal and masseteric nerve are branches of what nerve
Posterior and anterior division of V3 respectively
Clinical correlations of TMJ
> Dislocation of the jaw anteriorly: resulting from a blow against the jaw when opened
injury to the external auditory meatus
Crepitus of the TMJ: arises from delayed movement or tear in the articular disc. It’s the grinding sound of the TMJ e. g when chewing.
Branching of facial and auriculotemporal nerve arising near the joint.
Arthritis
Locking of TMJ or trismus
Venous drainage of the TMJ
> Maxillary vein
Pterygoid venous plexus
Facial veins (ant. and post. May have come toon with 1st and 2nd)
Pterygoid venous plexus o is located within what and drains into what
Infratemporal fossa
Maxillary vein (it receives blood from the surrounding structures and TMJ)
Maxillary vein + superficial temporal vein forms what within where
Retromandibular vein
Parotid gland
Location of the infratemporal fossa
Behind the maxilla
Infratemporal fossa communicates with the temporal fossa through the what
The space between the zarch and temple
Infratemporal fossa also communicates with the middle cranial fossa through the
Foramen spinosum and foramen ovale
What forms the superior boundary of the Infratemporal fossa ?
Greater wing of sphenoid and squamous part of temporal bone
What forms the inferior boundary of the Infratemporal fossa ?
No anatomical structure
What forms the medial boundary of the Infratemporal fossa ?
Lateral pterygoid plate of the sphenoid bone
What forms the lateral boundary of the Infratemporal fossa ?
Ramus of the mandible
What forms the anterior boundary of the Infratemporal fossa ?
Posterior surface of the maxilla
What forms the posterior boundary of the Infratemporal fossa ?
Mastoid and styloid process of temporal bone and tympanic plate
What are the contents of the Infratemporal fossa
> Muscles: Medial and lateral pterygoid muscles and lower part of the temporalis, buccinator.
Nerves: mandibular nerve and it’s branches plus the chords tympani branch
Artery: Maxillary artery and it’s branches
Veins: pterygoid plexus, maxillary veins
Ganglion: Otic ganglion
Ligament: sphenomandibular ligament.
Location of the pterygopalatine fossa
It’s a small fossa located lateral to the Infratemporal fossa and below to the apex of the orbit. Lies between the lateral pterygoid plate and the maxilla.
What and what opens into the pterygopalatine fossa
Pterygoid canal and
Anterior wall of the foramen lacerum
What forms the anterior boundary of the pterygopalatine fossa?
Posterior surface of the maxilla
What forms the posterior boundary of the pterygopalatine fossa?
Pterygoid process of sphenoid bone
What forms the medial boundary of the pterygopalatine fossa?
Perpendicular plate of palatine bone
What forms the superior boundary of the pterygopalatine fossa?
Greater wing of sphenoid bone
What forms the inferior boundary of the pterygopalatine fossa?
Pyramidal process of palatine bone
What communicates with the Infratemporal fossa anterio-sup with the orbit
through the superior orbital fissure
What communicates with the Infratemporal fossa posterio-sup with middles cranial fossa through
Foramen rotundum and pterygoid canal
What communicates with the Infratemporal fossa laterally with Infratemporal fossa through
Pterygomaxillary fissure
What communicates with the Infratemporal fossa medially through the
Sphenopalatine foramen
Contents of Infratemporal fossa
Pterogopaltine ganglion
Pharyngeal branch of maxillary artery
Maxillary artery (3rd part)
Maxillary nerve
Nerve of the pterygoid canal
Nasopalatine nerve and vessels
Greater palatine nerve
Inferior orbital fissure
Clinical correlation
Lesion of the CN V3 can cause unilateral paralysis of muscke followed by atrophy
Nerve block carried out in nerves in the fossa to block sensation
The arteries create an anastomotic channel between the external and internal carotid arteries
Why are the bong landmarks of the posterior triangle
Joy Thanked Chioma and Hilda Of Precious First Friutful School
. Jugular foramen
. Transverse process of cervical vertebrae
. Carotid canal
. Hypoglossal canal
. Occipital condyles
. Pharyngeal tubercle
. Foramen magnum
. First rib
.m
. Styloid process
OIIABS of Temporalis muscle
O: temporal fossa
I: Coronoid process and anterior border of ramus of mandible
I: Deep temporal branches of mandibular nerve
A: anterior fibres- elevate the mandible
Posterior- retracts the mandible
Blood supply: Deep temporal branches from maxillary artery, middle temporal branch from superficial temporal artery
OIIABS of masseter muscle
O: Zygomatic arch
I: Ramus and angle of mandible
I: Masseteric branch of the CN V3
A: Elevation of the mandible
Superficial fibres: protracts the mandible
Deep fibres: retracts the mandible
BS: Masseteric artery
Lateral pterygoid muscle OIIABS
O: upper head- Infratemporal surface of greater wing of sphenoid bone
Inferior head- lateral surface of the lateral pterygoid plate
I: pterygoid fovea and capsule of TMJ
I: superior head and lateral half of inferior head: buccal branch of CN V3
Medial half of inferior head: directly from CN V3
A: depresses the mandible and protracts the mandible, moves the mandible from side to side
Blood supply: pterygoid branches of the maxillary artery and the ascending palatine branch of the facial artery.
OIIABS of medial pterygoid muscle
O: Deep head - medial surface of lateral pterygoid plate
Superficial head: Tuberosity of maxilla
I: inner/ medial surface of angle and ramus of mandible
I: Medial pterygoid nerve (of mandibular nerve (CN V3)
A: elevates the mandible , protracts the mandible
Blood supply: Pterygoid branches (maxillary artery, buccal artery, facial artery)
