Infratemporal Fossa Flashcards
Outline the boundaries of the temporal fossa and the infratemporal fossa. Identify the contents
of each area, including muscles, Neurovasculature, ligaments, etc.
The temporal fossa is a depression surrounded by the superior and inferior temporal lines. It contains the temporalis muscle.
Boundaries of infratemporal fossa:
Superior: greater wing of sphenoid and squamous temporal bones
Inferior: open bottom filled by medial pterygoid m.
Medial: lateral pterygoid plate
Lateral: ramus and condyle mandible
Anterior: Maxilla
Posterior: Not bony
Contents of infratemporal fossa: Inferior portion of temporalis muscle Lateral and medial pterygoid muscles Maxillary artery and its branches Pterygoid venous plexus Branches of CN V3 Chorda tympani Otic ganglion
What is the innervation of the muscles of mastication?
All are innervated by branches of CNV3 (the mandibular branch of trigeminal nerve.
The maxillary artery is a terminal branch of what vessel?
The maxillary artery is a terminal branch of the external carotid artery.
List the branches of the maxillary artery in the mandibular, pterygoid, and pterygopalatine
segments. What does each supply?
Mandibular Portion:
1) Deep auricular artery-supplies external acoustic meatus and lateral tympanic membrane
2) Anterior tympanic artery- supplies middle ear cavity
3) Middle meningeal artery- supplies dura mater & calvaria (via foramen spinosum)
4) Accessory middle meningeal artery-supplies dura mater and calvaria (via foramen ovale)
5) Inferior Alveolar Artery- supplies mandible & teeth (via mandibular foramen & canal) and gives off mental artery.
Pterygoid Portion
1) Deep temporal arteries-(ant. and post.) supply temporalis muscle
2) Pterygoid arteries-supply lateral and medial pterygoid muscles
3) Artery to masseter- supplies masseter muscle (Duh)
4) Buccal artery- supplies to buccinator muscle
Pterygopalatine Portion
1) Posterior superior alveolar artery
2) Infra-orbital artery
3) Descending palantine artery
4) Artery of the pterygoid canal
5) Pharyngeal artery
6) Sphenopalatine artery
What is the pterygoid venous plexus and what does it communicate with?
Valveless venous equivalent for most of the maxillary artery, which communicates with the facial vein, cavernous sinus, pharyngeal plexus, retromandibular vein, and opthalmic vein.
List the motor and sensory branches of CN V3 and what each supplies. Think about what sensory and motor deficits would result from a lesion of CN V3 at foramen ovale, the mandibular foramen, and in the floor of the mouth.
Motor branches:
- Deep temporal nerves: supply temporalis m.
- Masseteric nerve: supplies masseter m.
- Nerve to lateral pterygoid
- Nerve to medial pterygoid
- Nerve to tensor tympani m.
- Nerve to tensor veli palatini m.
- Nerve to mylohyoid m.
Sensory Branches
- Auricotemporal Nerve: supplies TMJ, auricle and external meatus, anterior surface of tympanic membrane and temporal region
- Inferior Alveolar nerve: mandibular teeth (also gives off mental nerve, which supplies skin and mucous membranes of the lower lip and skin of the chin.)
- Lingual Nerve: anterior 2/3 of the tongue, mucosa of the floor of the mouth, and mandibular lingual gingivae
- Long buccal nerve: skin over the cheek, mucous membrane lining the cheek
Where is the otic ganglion found? With what cranial nerve is it associated?
The otic ganglion is located inferior to foramen ovale, medial to the root of CN V3, and posterior to medial pterygoid. It is associated with the glossopharyngeal nerve.
What branch of CN V3 do parasympathetics from the submandibular ganglion hitch a ride on?
The lingual nerve.
What would result if the LINGUAL nerve were lesioned proximal to (BEFORE) its union with chorda
tympani?
You would lose sensory (pain/temp/touch) to the anterior 2/3rd of the tongue, mucosa of floor of mouth, and the mandibular gingivae. However, functions of Chorda tympani would be intact, which = taste to anterior 2/3rd of tongue and pregang parasympathetics headed to submandibular or sublingual glands
What would result if lingual nerve were lesioned distal to the submandibular ganglion?
If the lingual nerve was lesioned distal to the submandibular ganglion, then you would lose taste and general sensation to the anterior 2/3 of the tongue as well as parasympathetic innervation to the sublingual gland.
What forms the temporomandibular joint (TMJ)? What actions does this joint accomplish?
TMJ formed by 3 bony arcticulating surfaces: mandibular condyle/head, mandibular fossa, and articular tubercle of the temporal bone. It is a modified hinge joint with upper and lower articular cavities:
- Upper does gliding (ant. protrusion and post. retrusion),
- Lower does hinge movements (elevation and depression)
What muscles act on the TMJ?
ALL the muscles of mastication! Include (4): Temporalis, Masseter, Lateral Pterygoid, and Medial Pterygoid mm
What ligaments stabilize the TMJ?
(3) total: two extrinsic ligaments and the lateral ligament (intrinsic) connect the mandible to the cranium. Extrinsic =
- Stylomandibular ligament: runs from styloid process to angle of mandible. Not significant contribution to joint strength.
- Sphenomandibular ligament: runs from spine of sphenoid to lingular of mandible medial to TMJ. Does primary passive support of mandible (active tonus by mm of mastication)
- Lateral ligament of TMJ (intrinsic) is thickened of part joint capsule around condylar head. Prevents posterior and inferior dislocation of the joint.
What nerves provide sensory innervation to the TMJ and would carry pain if it were damaged?
The Auriculotemporal n (branch of V3) provides primary sensory innervation of the TMJ.
Which muscles of mastication close the mouth? Which ones act to open the mouth?
Elevation (close mouth) = Temporalis, masseter, and medial pterygoid
Depression (open mouth) = mostly gravity with some action by Inferior heads of Lateral Pterygoid
