Infratemporal Fossa Flashcards
Temporal Fossa
Shallow depression on the lateral sides of the skull.
Temporal Fossa Boundaries
Anterior boundary: frontal/zygomatic bounds. Posterior and superiorly: temporal lines. Laterally: Zygomatic arch. Inferiorly: Infratemporal Crest
Floor of Temporal Fossa
frontal, parietal, temporal bones and the greater wing of the sphenoid bone (these are the 4 bones that come together to form the pterion)
Contents of Temporal Fossa
Temporalis muscle and fascia, Masseter Muscle
Temporalis Muscle
The large fan-shaped temporalis muscle takes origin from the floor of the temporal fossa and the fascia that envelops the muscle. Functions to elevate and retract the mandible.
Temporal Fascia
Fascia of the temporalis muscle forms the roof of the temporal fossa and extends from the superior temporal line to the zygomatic arch
Masseter Muscle
Masseter originates from the zygomatic arch and the zygomatic bone and inserts on the external surface of the ramus and angle of the mandible. Functions to elevate and protrude mandible. Below the zygomatic arch, the deep fascia of the masseter is continuous with the deep fascia of the temporalis.
Infratemporal Fossa
Irregular space located posterior to the maxilla and deep to the ramus of the mandible. Behind the zygomatic arch (superiorly), continues with the temporal fossa
Boundaries of Infratemporal Fossa
Lateral Wall: Ramus of the mandible. Medial Wall: lateral pterygoid plate of sphenoid bone. Superior Boundary: Infratemporal crest of sphenoid. Inferior boundary: Angle of mandible
Contents of Infratemporal Fossa
Temporalis Muscle (inferior portion). Medial Pterygoid muscle. Lateral pterygoid muscle. Maxillary artery. Pterygoid venous plexus. CNV2. Chorda Tympani. Otic Ganglion
Temporalis Muscle (Inferior Portion)
Content of Infratemporal Fossa. Runs from the floor of the temporal fossa and temporal fascia to the coronoid process and medial surface of ramus of mandible.
Medial Pterygoid Muscle
Runs from medial surface of lateral pterygoid plate to internal surface of ramus of mandible
Lateral Pterygoid Muscle
Runs from lateral surface of the lateral pterygoid plate to the TMJ and neck of condyloid process
Maxillary Artery
Larger of the two terminal branches of External Carotid. Arises posterior to the neck of the mandible. Divided into three parts by the lateral pterygoid muscle.
1st part of maxillary artery
Runs from origin to the lateral border of the lateral pterygoid muscle. 5 branches: Deep auricular, anterior tympanic, middle meningeal, accessory meningeal, inferior alveolar
Deep auricular Artery
Runs to external acoustic meatus. Branch of 1st part of maxillary artery
Anterior Tympanic Artery
Runs to tympanic membrane. Branch of 1st part of maxillary artery
Middle Meningeal Artery
Runs to the cranial meninges through foramen spinosum. Branch of 1st part of maxillary artery
Accessory Meningeal Artery
Runs to the cranial meninges through the foramen ovale. Branch of 1st part of maxillary artery
Inferior Alveolar Artery
Runs to the mandibular teeth through mandibular foramen. Branch of 1st part of maxillary artery
2nd part of maxillary artery
Portion of Maxillary that lies over the lateral pterygoid muscle. It provides: Masseteric branches, deep temporal branches, pterygoid branches, and buccal branches.
Masseteric Artery
Supply the masseter muscle. Branch of 2nd part of maxillary artery
Deep Temporal Artery
Supply the temporalis muscle. Divides into anterior and posterior branches. Branch of 2nd part of maxillary artery
Pterygoid Arteries
Supply medial and lateral pterygoid muscles. There is both a lateral and a medial pterygoid artery. Branches of 2nd part of maxillary artery
Buccal Artery
Supply the muscles of the cheek. Branch of 2nd part of maxillary artery
3rd Part of Maxillary Artery
Extends from medial edge of lateral pterygoid to its termination in the pterygoid fossa. Provides the following branches: Posterior superior alveolar artery, infraorbital artery, descending palatine artery, and sphenopalatine artery
Posterior Superior alveolar artery
Supplies the molar and premolar teeth. Divides into further branches (not mentioned in hand out). Branch of 3rd part of maxillary artery
Infraorbital Artery
Emerges from infraorbital foramen below orbit. Through its branches (not discussed in hand out) supplies blood to upper teeth and muscles of the eye. Branch of 3rd part of maxillary artery
Descending Palatine Artery
Emerges through greater palatine foramen. Terminal branch anastomoses with sphenopalatine artery. Supplies gums, palatine glands, and mucuous membrane of roof of mouth. Branch of 3rd part of maxillary artery
Sphenopalatine Artery
Passes through sphenopalatine foramen into nose. Anastomoses with branches of descending palatine artery. Branch of 3rd part of maxillary artery
Pterygoid Venous Plexus
Venous plexus located in the infratemporal Fossa. Veins of the plexus make connections with the facial vein laterally and the cavernous sinus medially. The small veins of the plexus usually join together to give rise to one or two larger veins known as the maxillary veins. D. The maxillary veins leave the infratemporal fossa and join with the superficial temporal vein, in the parotid gland, to form the retromandibular vein
Superficial Temporal Vein
Joins with maxillary to form Retromandibular Vein
Maxillary Vein
Veins of venous plexus join together and give rise to a maxillary vein. Maxillary vein joines with superficial temporal vein to form retromandibular
Retromandibular
Formed by joining of maxillary and superficial temporal
Mandibular Division of CNV
Only division of CNV with motor fibers. It is the only nerve in the infratemporal region (except for the chorda tympani). It exits the skull through foramen ovale to enter the fossa.
Motor Branches of CNV3
Motor branches go to the following muscles: muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini
Sensory Branches of CNV3
Auriculotemporal nerve, buccal nerve, inferior alveolar nerve (gives off a motor branch prior to sensory branches), Lingual nerve
Auriculotemporal Nerve
Encircles middle meningeal artery and supplies auricle, skin over temporal region, TMJ, external auditory meatus, tympanic membrane, secretory parasympathetic fibers to the parotid (Fibers belonging to CNIX but travel with Auriculotemporal. *Described in previously lecture)
Buccal Nerve (Long Buccal)
Supplies skin and mucuous membrane of cheek, lateral surface of oral gingiva.
Inferior Alveolar Nerve
Supplies all teeth on its side of the mandible. Before passing through mandibular foramen, gives off Mylohyoid nerve (MOTOR NERVE) to innervate mylohyoid. Passes through mandibular foramen to enter the mandible. Gives off Mylohyoid nerve (also supplies anterior digastric muscle), Mental nerve, and incisive nerve
Mylohyoid nerve
Branch of inferior alveolar nerve given off before it enters mandibular foramen. Supplies anterior belly of digastric muscle and mylohyoid muscle.
Mental Nerve
Branch of inferior alveolar. Supplies skin of chin. Exits inferior alveolar canal through mental foramen
Incisive nerve
Branch of inferior alveolar. Continues further through mandible after mental nerve given off, supplies canine and incisor teeth [Not pictured in slides because interior]
Inferior Alveolar Nerve Block
A type of anesthetic typically applied at dentist. Anesthetic agent injected near the mandibular foramen, spreads through the sensory branches of CNV3 in a proximal manner (closest regions first).
Lingual Nerve
sensory to the tongue, floor of the mouth and gingiva
Chorda Tympani
Branch of CNVII. Leaves the CN VII and exits the skull to join the lingual nerve in the infratemporal fossa. Conveys taste from the anterior 2/3 of the tongue (minus vallate papillae). Conveys preganglionic parasympathetic fibers to the submandibular ganglion. Postganglionic fibers from the submandibular ganglion then go to the submandibular gland, sublingual gland and other smaller salivary glands
Otic Ganglion
Parasympathetic Ganglion located in the infratemporal fossa. Preganglionic parasympathetic fibers enter the ganglion via the lesser petrosal nerve. Contains the cells bodies of the postganglionic parasympathetic neurons. Contains the cells bodies of the postganglionic parasympathetic neurons
Temporomandibular Joint
Modified hinge joint (type of synovial joint) between the condyle of the mandible and either the articular process of the mandible or the mandibular fossa depending on the state of the jaw/chewing. Articular surfaces are covered with fibrous tissues
Mandibular Fossa
Depression in temporal bone. Condyle can articulate here as part of TMJ
Articular Eminence/Tubercule
Bony protrustion of temporal bone. Condyle can articulate with this as part of TMJ
Articular disc
fibrous tissue and not fibrocartilage - attached to the capsule
Upper Cavity
Upper (gliding) joint. Between the articular eminence, mandibular fossa and the articular disc. condyle and the disc slide forward onto the articular eminence when opening jaw
Lower Cavity
Lower hinge joint. Between the articular disc and the condyle of the mandible.
Capsule
attached to margins of articular area of temporal bone and around neck of mandible
Where the condyle sits/articulates when jaw is closed/teeth clenched
Condyle in mandibular Fossa
Where the condyle sits/articulates when jaw is at rest
Condyle against articular eminence
Where the condyle sits/articulates when jaw is wide open
Condyle below articular eminence
Stylomandibular Ligament
Band of deep cervical fascia from styloid process to angle of mandible
Sphenomandibular Ligament
Membranous band from spine of sphenoid to lingula of mandible
Lateral Ligament
Small, attached to capsule and articular disc. Only one of the 3 that is actually attached to the TMJ. Checks mediolateral movement of TMJ
Which muscles control opening of TMJ/mandible?
depression (gravity) supra/infrahyoids
Which muscles control closing of TMJ/mandible?
elevation, temporalis and masseter mainly
Which muscles control protraction of TMJ/mandible?
(protrusion) lateral pterygoids and masseter mainly
Which muscles control retrustion of TMJ/mandible?
(retrusion) posterior (horizontal) fibers of temporalis
Which muscles control lateral movement of TMJ/mandible?
Retractors of the same side (temporalis muscle). Protruders of the opposite side (lateral pterygoids)
Which CN supplies motor innervation to all muscles of mastication?
CNV
Which branches of CNV supply sensory innervation to the TMJ?
Masseteric nerve, auriculotemporal nerve.
Dislocating the TMJ
Yawning, taking a large bite, a sideway blow to the chin when mouth is open. Largest risk WHEN MOUTH IS OPEN because condyle is no longer in a fossa (look at picture). Can cause damage to auriculotemporal nerve.
