Podcast
Questions and Answers
Which muscle is primarily responsible for the protraction of the mandible during mastication?
Which muscle is primarily responsible for the protraction of the mandible during mastication?
What is the primary action occurring in the superior compartment of the temporomandibular joint (TMJ)?
What is the primary action occurring in the superior compartment of the temporomandibular joint (TMJ)?
Which cranial nerve branch is responsible for innervating the muscles of mastication?
Which cranial nerve branch is responsible for innervating the muscles of mastication?
Which ligament connects the mandible to the cranium via the spine of the sphenoid bone?
Which ligament connects the mandible to the cranium via the spine of the sphenoid bone?
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Which of the following movements is NOT typically associated with the temporomandibular joint?
Which of the following movements is NOT typically associated with the temporomandibular joint?
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What is the role of the articular disc in the temporomandibular joint?
What is the role of the articular disc in the temporomandibular joint?
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What happens during anterior dislocation of the TMJ?
What happens during anterior dislocation of the TMJ?
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Which muscle of mastication assists in the elevation and retraction of the mandible?
Which muscle of mastication assists in the elevation and retraction of the mandible?
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Which muscle primarily serves as a protractor for the mandible?
Which muscle primarily serves as a protractor for the mandible?
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Which of the following muscles is innervated by the mandibular branch of CN V (V3)?
Which of the following muscles is innervated by the mandibular branch of CN V (V3)?
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What action is primarily associated with the contraction of the posterior fibers of the temporalis muscle?
What action is primarily associated with the contraction of the posterior fibers of the temporalis muscle?
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During lateral movement of the jaw to the right, which muscles are contracted?
During lateral movement of the jaw to the right, which muscles are contracted?
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Which muscle of mastication is specifically responsible for the depression of the mandible?
Which muscle of mastication is specifically responsible for the depression of the mandible?
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Which muscles primarily contribute to the elevation of the mandible during mastication?
Which muscles primarily contribute to the elevation of the mandible during mastication?
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Where do the upper and lower heads of the lateral pterygoid muscle attach?
Where do the upper and lower heads of the lateral pterygoid muscle attach?
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Which structure is located inferior to the zygomatic arch and deep to the ramus of the mandible?
Which structure is located inferior to the zygomatic arch and deep to the ramus of the mandible?
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Which muscle's primary function includes both elevation and protraction of the mandible?
Which muscle's primary function includes both elevation and protraction of the mandible?
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What is the main anatomical relationship of the temporalis muscle?
What is the main anatomical relationship of the temporalis muscle?
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Study Notes
Infratemporal Fossa
- Located inferior to the zygomatic arch, deep to the ramus of the mandible and posterior to the maxilla bone
- Contains the temporalis muscle, medial and lateral pterygoid muscles, maxillary artery, and venous plexus
- The following nerves are present in the infratemporal fossa: mandibular nerve, inferior alveolar nerve, lingual nerve, and buccal nerve
Temporomandibular Joint
- A diarthrodial (synovial) joint
- Articulation between the articular tubercle & mandibular fossa of the temporal bone and mandibular condyle of the mandible
- The articular disc divides the joint into 2 compartments:
- Protraction and retraction occur in the superior compartment.
- Elevation and depression occur in the inferior compartment.
Muscles of Mastication
-
Temporalis muscle:
- arises from the floor of the temporal fossa and deep temporal fascia.
- inserts to medial surface, apex, and anterior/posterior borders of coronoid process of mandible and anterior border of ramus of mandible.
- action: elevates mandible (closes mouth & teeth) and retracts (pulls back mandible).
- innervation: mandibular branch of CN V (V3).
-
Masseter muscle:
- arises from the inferior border and medial surface of the zygomatic arch.
- inserts onto the angle and lateral aspect of the ramus of the mandible.
- action: powerfully elevates the mandible (closes mouth).
- innervation: mandibular branch of CN V (V3).
-
Lateral Pterygoid muscle: has 2 heads:
- Upper head: arises from infratemporal surface and crest of greater wing of sphenoid
- Lower head: arises from the lateral surface of the lateral pterygoid plate
- both heads insert onto the anterior aspect of the mandibular neck, articular capsule, and TMJ disc
- action: chief protractor (moves mandible forward) and depresses (opens) mandible.
- innervation: mandibular branch of CN V (V3).
-
Medial Pterygoid muscle: has 2 heads:
- arises from medial surface of the lateral pterygoid plate, palatine bone, and the tuberosity of the maxilla.
- inserts onto the medial surface of the mandibular angle.
- action: elevates and protracts (moves forward and brings mandible up) the mandible.
- innervation: mandibular branch of CN V (V3).
TMJ Movements
- Elevation: temporalis, masseter, medial pterygoid
- Depression: lateral pterygoid, digastric
- Protraction (forward movement) : lateral pterygoid, medial pterygoid
- Retraction (backward movement) : posterior fibers of temporalis
-
Lateral Movements:
- ipsilateral - temporalis & masseter (pull)
- contralateral - medial & lateral pterygoid (push)
TMJ Ligaments
- Lateral temporomandibular ligament: thickening of the joint capsule; prevents posterior dislocation of the joint with the help of the postglenoid tubercle.
- Sphenomandibular ligament: connects the lingula of mandible to the cranium via the spine of the sphenoid bone.
- Stylomandibular ligament: connects the mandible to the cranium via the styloid process of the temporal bone.
TMJ Dislocation
- Posterior dislocation is not common.
- Anterior dislocation (excessive contraction of lateral pterygoids while opening the mouth): the mandible remains depressed and is unable to close.
TMJ Clicking
- May indicate a delayed movement of the disc and often points to a tear of the disc.
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Description
This quiz covers the anatomy of the infratemporal fossa, including its location, contents like muscles and nerves, and the details about the temporomandibular joint (TMJ). It also discusses the muscles involved in mastication and their functions. Perfect for students studying anatomy related to the jaw and facial structures.
