Week 19 - Infratemporal Fossa & Muscles of Mastication Flashcards
What does the temporal region of the head include?
Lateral area of the scalp and deeper soft tissues overlying the temporal fossa
Superior to the zygomatic arch
What primarily occupies the temporal fossa?
Upper portion of the temporalis muscle
What are the boundaries of the temporal fossa?
- Posteriorly and superiorly: temporal lines
- Anteriorly: frontal and zygomatic bones
- Laterally: zygomatic arch
- Inferiorly: infratemporal crest
Which bones form the floor of the temporal fossa?
- Frontal
- Parietal
- Temporal
- Greater wing of the sphenoid
What does the temporal fascia cover?
Temporalis muscle, attaching superiorly to the superior temporal line
What structure provides resistance when the masseter muscle contracts?
Temporal fascia
Where is the infratemporal fossa located?
Deep and inferior to the zygomatic arch, deep to the ramus of the mandible, and posterior to the maxilla
What are the boundaries of the infratemporal fossa?
- Laterally: ramus of the mandible
- Medially: lateral pterygoid plate
- Anteriorly: posterior aspect of the maxilla
- Posteriorly: tympanic plate and mastoid and styloid processes of the temporal bone
- Superiorly: inferior surface of the greater wing of the sphenoid
- Inferiorly: medial pterygoid muscle attachment
What structures are contained within the infratemporal fossa?
- Inferior part of the temporalis muscle
- Lateral and medial pterygoid muscles
- Maxillary artery
- Pterygoid venous plexus
- Mandibular, inferior alveolar, lingual, buccal, and chorda tympani nerves
- Otic ganglion
What type of joint is the temporomandibular joint (TMJ)?
Modified hinge type of synovial joint
What movements are permitted by the TMJ?
- Gliding (translation)
- Small degree of rotation (pivoting)
- Flexion (elevation)
- Extension (depression)
What are the bony articular surfaces involved in the TMJ?
- Mandibular fossa of the temporal bone
- Articular tubercle of the temporal bone
- Head of the mandible
What separates the two bony articular surfaces in the TMJ?
Intervening fibrocartilage, the articular disc of the TMJ
What is the function of the intrinsic lateral ligament of the TMJ?
Strengthens the joint laterally and prevents posterior dislocation
What is the primary passive support of the mandible?
Sphenomandibular ligament
Which muscles elevate the mandible?
- Temporalis
- Masseter
- Medial pterygoid
What muscle primarily depresses the mandible?
Lateral pterygoid
Which muscles are involved in the protrusion of the mandible?
- Lateral pterygoid
- Masseter
- Medial pterygoid
What is the role of the lateral pterygoid during retrusion of the mandible?
Prime mover for retrusion
How does the head of the mandible move during mouth opening?
Moves anteriorly on the articular surface until it lies inferior to the articular tubercle
What are the four muscles of mastication?
- Temporalis
- Masseter
- Medial pterygoid
- Lateral pterygoid
What nerve innervates the muscles of mastication?
Mandibular nerve (CN V3)
What is the origin of the temporalis muscle?
Floor of temporal fossa and deep surface of temporal fascia
What is the action of the medial pterygoid muscle?
Acts synergistically with masseter to elevate mandible
What is the course of the maxillary artery?
Arises posterior to the neck of the mandible and is divided into three parts
What are the branches of the first part of the maxillary artery?
- Deep auricular artery
- Anterior tympanic artery
- Middle meningeal artery
What does the middle meningeal artery supply?
Periosteum, bone, red bone marrow, dura mater of lateral wall and calvaria of neurocranium
What is the location and orientation of the pterygoid muscle?
Runs horizontally, deep (medial) to neck of condylar process of mandible and lateral to stylomandibular ligament
What does the deep auricular artery supply?
External acoustic meatus, external tympanic membrane, and temporomandibular joint
What is the function of the anterior tympanic artery?
Supplies internal aspect of tympanic membrane
What does the middle meningeal artery supply?
Periosteum, bone, red bone marrow, dura mater of lateral wall and calvaria of neurocranium, trigeminal ganglion, facial nerve and geniculate ganglion, tympanic cavity, and tensor tympani muscle
Where does the accessory meningeal artery enter the cranial cavity?
Via foramen ovale
What are the main supplies of the inferior alveolar artery?
Mandible, mandibular teeth, chin, mylohyoid muscle
What does the masseteric artery supply?
Temporomandibular joint and masseter muscle
What do the deep temporal arteries supply?
Mainly the temporalis muscle
What do the pterygoid branches supply?
Pterygoid muscle
What does the buccal artery supply?
Buccal fat-pad, buccinator, and buccal oral mucosa
What does the posterior superior alveolar artery supply?
Maxillary molar and premolar teeth, adjacent gingiva, and mucous membrane of maxillary sinus
What is the route of the infra-orbital artery?
Traverses inferior orbital fissure, infra-orbital groove, canal, and foramen
What does the artery of pterygoid canal supply?
Mucosa of upper pharynx, pharyngotympanic tube, and tympanic cavity
What does the pharyngeal branch supply?
Mucosa of nasal roof, nasopharynx, sphenoidal air sinus, and pharyngotympanic tube
What does the descending palatine artery divide into?
Greater and lesser palatine arteries
What is the terminal branch of the maxillary artery?
Sphenopalatine artery
Where is the pterygoid venous plexus located?
Partly between the temporalis and pterygoid muscles
What is the function of the mandibular nerve?
Arises from the trigeminal ganglion and supplies the muscles of mastication
What are the branches of CN V3?
- Auriculotemporal nerve
- Inferior alveolar nerve
- Lingual nerve
- Buccal nerve
What does the auriculotemporal nerve supply?
Sensory fibers to the auricle and temporal region
What does the inferior alveolar nerve form in the mandibular canal?
Inferior dental plexus
What does the lingual nerve provide sensory innervation to?
Anterior two thirds of the tongue, floor of the mouth, and lingual gingivae
What nerve carries taste fibers from the anterior two thirds of the tongue?
Chorda tympani nerve
Where is the otic ganglion located?
Infratemporal fossa, just inferior to the foramen ovale
What type of fibers synapse in the otic ganglion?
Presynaptic parasympathetic fibers
What gland receives postsynaptic parasympathetic fibers from the otic ganglion?
Parotid gland
