Sem 2 - S - Infratemporal fossa and T.M.J - Fossa Boundaries/contents, TMJ strucute/ligaments/function Flashcards
What is the infratemporal fossa? What muscle is the infratemporal fossa found deep to?
The infratempora fossa is the space beneath the skull - between the skull and the ramus of the mandible
- The infratemporal fossa is found deep to the masseter muscle
What are the boundaries of the infratemporal fossa? (anterior, posterior, superior, medial, lateral)
- Anterior - posterior surface of maxilla
- Posterior - styloid process of temporal bone
- Superior - infratemporal surface of the greater wing of sphenoid bone
- Medial - lateral pterygoid plate of sphenoid bone
- Lateral - ramus of the mandible
What is the fissure formed between the pterygoid process and the maxilla? What passes through here?
The pterygomaxillary fissure The third part of the maxillary artery, the pterygopalatine part passes through this fissure to reach the pterygopalatine fossa
What are the contents of the infratemporal fossa?
- * Medial and lateral pterygoid muscles
- * Mandibular division of trigeminal nerve and branches (CN V3 and branches)
- * Maxillary artery and branches
- * Pterygoid venous plexus
- * Chorda tympani
- * Otic ganglion
Contents of infratemporal fossa Medial and lateral pterygoid muscles, mandibular nerve and branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, otic ganglion
State the attachment, function and nerve supply to the lateral pterygoid muscle
- Attachment -
- Upper head from the infratemporal surface of the greater wing of the sphenoid bone,
- Lower head from the lateral surface of the lateral pterygoid plate
- Inserts into the neck of the mandible & articular disc of TMJ
- Function -
- Bilateral pulls the neck of the mandible forward with the articular disc (protrusion),
- Unilateral helps in lateral chewing with medial pterygoid, and depressed mandible
- Innervation - Nerve to lateral pterygoid from anterior division of CN V3
What is the attachment function and nerve supply of the medial pterygoid muscle?
- Attachment -
- Superficial head from the tubercle of the maxilla,
- Deep head from the medial surface of the lateral surface of pterygoid plate of sphenoid bone
- Inserts into the medial surface of the angle of the mandible
- Function - assist in elevation of the mandible, assists in lateral chewing of mandible with medial pterygoid
- Innervation - Nerve to medial pterygoid from main trunk of CN V3
Contents of infratemporal fossa Medial and lateral pterygoid muscles, mandibular nerve and branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, otic ganglion
What are the branches of CN V3?
- Main trunk -
- Meningeal nerve and nerve to medial pterygoid (gives branches to tensor tympani and tensor veli palatini)
- Anterior -
- Deep temporal nerves x2, nerve to lateral pterygoid, masseteric nerve (motor)
- and buccal nerve (sensory)
- Posterior division-
- Inferior alveolar nerve (giving mylohyoid nerve)
- Auriculotemporal nerve, lingual nerve
Contents of infratemporal fossa Medial and lateral pterygoid muscles, mandibular nerve and branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, otic ganglion
Talked about the muscles and mandibular nerve and its branches Lets talk about the maxillary artery
- What is this artery one of the terminal branches of?
The maxillary artery is one of the terminal branches of the external carotid artery along with the superficial temporal artery
The maxillary artery can be divided into three parts What are these three parts? Where does the maxillary artery run?
Can be divided into manidbular part, pyterygoid part and pterygopalatine part
Maxillary artery will run in infratemporal fossa and pass between the upper and lower heads of the lateral pterygoid muscle to go into the pterygopalatine fossa via the pterygomaxillary fissure
The first and second part of the maxillary artery lie within the infratemporal fossa The maxillary artery then passes through the pterygomaxillary fissure and the third part lies within the pterygopalatine fossa
What is the mnemonic to help remember the branches of the maxillary artery?
* DAM, I, AM, Piss, Drunk, But, Stupid, Drunk, I, Prefer, Must, Phone, Alcoholics, Anonymous
State the branches coming from the mandibular part of the maxillary artery? (5 branches) (DAM I A)
- * Deep auricular artery
- * Anterior tympanic artery
- * Middle meningeal artery
- * Inferior alveolar artery
- * Accessory meningeal artery
State the branches coming from the pteryoid part of the maxillary artery ( 5 branches) (M Piss Drunk(x2) But)
- * Masseteric artery
- * Pterygoid arterial branches
- * Deep temporal artery (anterior and posterior)
- * Buccal artery
State the branches coming from the pterygopalatine part of the maxillary artery (6 branches, but mnemonic has 8 available because includes 2 branches from infraorbital artery) (Stupid Drunk I Prefer, Must Phone Alcoholics Anonymous)
- * Sphenopalatine artery
- * Descending palatine artery
- * Infraorbital artery
- * Posterior superior alveolar artery
- * Middle superior alveolar artery
- * Pharyngeal artery
- * Artery of pterygoid canal
- * Anterior superior alveolar artery
Anterior superior alveolar and middle superior alveolar are branches of the infraorbital artery
State all the branches of the different parts of the maxillary artery again
- Which are branches of the infraorbital artery?
- What is the terminal branch of the maxillary artery?
DAM I AM Piss Drunk But Prefer Stupid Drunk I Prefer, Must Phone Alcoholics Anonymous
- Mandibular part -
- Deep auricular, Anterior tympanic, Middle meningeal, Inferior alveolar, Accessory meningeal
- Pterygoid part -
- Massteric, Pterygoid arterial branches, Deep temporal(x2), Buccal
- Pterygopalatine part -
- Sphenopalatine, Descending palatine, Infraorbital, Posterior superior alveolar, Middle superior alveolar, Pharyngeal branch, Anterior superior alveolar, Artery to pterygoid canal
Which are branches of the infraorbital artery? What is the terminal branch of the maxillary artery?
Infraorbital artery gives off anterior and middle superior alveolar arteries Terminal branch of maxillary artery is the sphenopalatine artery
Contents of infratemporal fossa Medial and lateral pterygoid muscles, mandibular nerve and branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, otic ganglion
What does the pterygoid venous plexus surround? What do the veins form from?
Pterygoid venous plexus surrounds the lateral pterygoid plate
- The veins form from the orbit, nasal and oral cavities
What does the pterygoid venous sinus communicate with which serves as a potential route for infection? Where does the venous plexus drain into?
Pterygoid venous plexus communicates with the cavernous sinus and the facial vein (route of infection from face, to ptyergoid venous plexus to cavernous venous dural sinus where the meinges are)
The venous plexus drains into the maxillary vein
Where does the maxillary vein drain?
Once the maxillary vein drains the pterygoid venous plexus, it joins with the superficial temporal vein to form the retromandibular vein
Contents of infratemporal fossa Medial and lateral pterygoid muscles, mandibular nerve and branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, otic ganglion
Where does the chorda tympani arise and how does it join the lingual nerve?
Chorda tympani arises from the facial nerve whilst in the facial canal and passes through the middle ear between malleus and incus
- It exits the middle ear through the petrotympanic fissure where it emerges into the infratemporal fossa medial to the TMJ
- It will then join with the lingual nerve from CN V3
What does the chorda tympani innervate?
The chorda tympani supplies parasympathetic secretomotor innervation to the submandibular and sublingual salviary glands, it also supplies special sensory (taste) to the anterior 2/3rds of the tongue
Describe how CN IX supplies parasympathetic secretomotor innervation to the parotid gland?
Once CN IX passes through the jugular foramen, it gives off a tympani branch which travels into the tymapnic cavity to reach the tympanic plexus. From here, the lesser petrosal nerve will emerge and travel through the foramen ovale to synapse in the otic ganglion. The fibres will then hitch a ride on the auriculotemporal nerve to reach the parotid gland
What artery does the auriculotemproal nerve enclose? What foramen does this artery pass through to enter the skull?
The auriculotemporal nerve encloses the middle meningeal artery which passes through the foramen spinosum to enter the skull with the meningeal branch from the main trunk of CN V3
Which nerves also pass through the otic ganglion? These nerves will not synapse unlike the lesser petrosal nerve
The symapthetics to the parotid gland form plexuses on the ECA which travel onto the maxillary and then the middle meningeal artery (mandibular of maxillary) where the fibres will pass through the otic ganglion and to the parotid gland via the auriculotemporal nerve
Nerve to tensor tymapni and tensor veli palatini also pass through otic ganglion to reach these muscles
WE have now discussed the infratemporal fossa boundaries and contents We will now discuss the temperomandibular joint Describe the articulations in the temporomandibular joint?
The tempormandibular joint is a synovial joint between the mandibular fossa and articular tubercle of the squamous part of the temporal bone superiorly and the head of the of the mandible inferiorly
What splits the TMJ into 2 synovial joint cavities each within its synovial membrane?
The articular disc splits the TMJ into 2 joint cavities each with a synovial membrane
What type of cartilage lines the TMJ?
What forms the capsule of the joint?
The temporamndibular joint is lined by fibrocartilage (rather than the usual hyaline cartilage that lines synovial joints)
The TMJ capsule is a fibrous capsule
What is the nerve supply to the TMJ?
The temproermandibular joint is innervated by the auriculotemporal nerve (posterior division of CN V3) and the maseteric nerve (anterior division of CN V3)
AGAIN
- * Describe the articulations in the temporomandibular joint?
- * What splits the TMJ into 2 synovial joint cavities each within its synovial membrane?
- * What type of cartilage lines the TMJ?
- * What forms the capsule of the joint?
- * What is the nerve supply to the TMJ?
- * The temporomandibular joint is a synovial joint between the mandibular fossa and articular tubercle of the squamous temporal bone superiorly and the head of the mandible inferiorly
- * The articular disc splits the joint into two cavities such that the articulating bones are never in contact
- * The articular surfaces of the joint are lined by fibrocartilage and a fibrous capsule coveres the joint
- * TMJ is innervated by the auriculotemporal & masseteric nerve
There are three extracapsular ligaments in the TMJ What is their function? What are their names?
The extracapsular TMJ ligaments act to stabilise the joint and reinforce the capsule
The capsule is reinforced by the lateral (temporomandibular) ligament and the sphenomandibular and stylomandibular ligaments medially
What is the attachments of the extracapsular ligaments of the TMJ? Which ligament separates the parotid and submandibular glands?
- Lateral(tempormandibular) ligament - from articular tubercle of the temporal bone to neck of mandibule
- Sphenomandibular ligament - sphenoid bone spine to the mandible
- Stylomandibular ligament - styloid process to the angle of mandible (separates submandibular and parotid glands)
Which muscles attaches to the neck of the mandible and articular disc?
The insertion of the two heads of the lateral pterygoid
As said the joint cavity is divided by a fibrous articular disc What does this disc cause for an increase in?
The disc increases the congruity of the articular surfaces
Because the disc splits the joint into two cavities, there are essentially two types of joint
- What are the two types and between which surfaces?
- Which movements are possible at each?
- Between the head of the mandible and disc - synovial hinge joint allowing for elevation and depression
- Between the disc, mandibular fossa and articular tubercle of squamous temporal bone - synovial gliding joint allowing for protrusion and retrusion
What movements cause the mouth to open and close?
Close mouth - elevation and retraction pull condyle backwards
Open mouth - both sides depression and protrusion to slide disc forwards towards articular tubercle
- Elevation and depression - hinge joint
- Retrusion and protrusion - gliding joint
What does asynchronous gliding result in?
Asynchronous gliding results in chewing
We have discussed the muscles of mastication - the main muscles responsible for movements of the jaw State what happens to the jaw during each movement
- Elevation
- Depression
- Protraction
- Retraction
- Lateral sliding
- Elevation - head of the mandible and the disc move backward and the head rotates on the lower surface of the disc
- Depression - head of the mandible rotates on the lower surface of the articular disc and mandible is pulled forward
- Protraction - head of the mandible and articular disc are pulled forward
- Retraction - head of the mandible and articular disc are pulled backward into the mandibular fossa
- Lateral sliding - protusion and retrusion combined
State which muscles are involved in each movement of the jaw
- Elevation
- Depression
- Protursion
- Retrusion
- Lateral sliding
- Elevation - Temporalis (anterior/superior fibres) Masseter, Medial pterygoid
- Depression- Gravity, Lateral pterygoid, Mylohyoid, Anterior belly of digastric and Geniohyoid
- Protrusion -Lateral pterygoid (medial pterygoid assists)
- Retrusion - Posterior fibres of temporalis
- Lateral sliding - Lateral and Medial pterygoids
