Mastication Flashcards
What is the zygomatic arch?
a bar of bone formed by the zygomatic process of the temporal bone, and the temporal process of the zygomatic bone [temporal + zygomatic]
What is the superior temporal line?
a line formed by the connection of the temporal fascia [parietal]
What is the inferior temporal line?
the most superior attachment site of the temporalis muscle. [parietal]
What is the spine of the sphenoid?
an inferior projection located posteriorly of the foramen spinosum. It is the superior attachment of the sphenomandibular ligament [sphenoid]
What is the mandibular fossa?
the cranial portion of the temporomandibular joint (TMJ); it articulates with the condyle of the mandible [temporal]
What is the petrotympanic fissure?
a slit of bone just distal to the mandibular fossa (medial); chorda tympani exits skull through this fissure [temporal]
What is the articular tubercle?
Inferior projection of the zygomatic arch which forms the anterior limit of mandibular fossa [temporal]
What is the infratemporal crest?
an inferior attachment site for the temporalis muscle [sphenoid]
What is the styloid process?
a thin, inferior projection of the temporal bone located posterior to the mandibular fossa, and anterior to the mastoid process. Superior attachment for stylomandibular ligament, and stylohyoid ligament. Also, an attachment site for the styloglossus, stylohyoid, and stylopharyngeus mm. [temporal]
What is the maxillary tuberosity?
the posteroinferior projection of the maxilla. Attachment site for a portion of the medial pterygoid m.
What is the greater wing of the sphenoid?
Superolateral projection from the body of the sphenoid; can be seen internally and externally and is largest component of sphenoid bone [sphenoid]
What is the foramen ovale?
A large, oval foramen, which transmits V3 (mandibular n.), lesser petrosal n., and accessory meningeal a. [sphenoid]
What is the lateral plate of the pterygoid process?
Lateral surface is attachment site of lateral pterygoid m.; medial surface is attachment site for medial pterygoid m. (relationships of the pterygoid mm. to lateral plate is the basis for medial vs. lateral in their names) [sphenoid]
What is the Ramus?
Ascending portion of mandible; continuous with body of mandible; provides attachment for all muscles of mastication [mandibule]
What is the lingula?
Sharp projection overlapping the mandibular foramen; attachment site for sphenomandibular ligament; palpable landmark for inferior alveolar n. anesthetic blocks [mandible]
What is the coronoid process?
Anterior projection of the ramus of the mandible; attachment site for temporalis m. [mandible]
What is the condylar process?
Consists of articular surface of mandible which is a component of the temporomandibular joint (TMJ) [mandible]
What is the pterygoid fovea?
Depression located on anterior surface of neck of the condylar process; attachment site for lateral pterygoid m. [mandible]
What is the temporal crest?
Ridge on medial surface of coronoid process that extends to approximately the 3rd molar; temporalis m. has an attachment here [mandible]
Temporals Superior/inferior attachment, innervation, and action
Temporal fossa - Coronoid process & ramus of mandible - Deep temporal brs. (V3) - Elevation of mandible (e.g. closing mouth); slight retraction of mandible
Masseter Superior/inferior attachment, innervation, and action
Maxilla & zygomatic arch - Angle & ramus of mandible - Masseteric n. (V3) - Elevation of mandible; retraction & protraction (dependent on fibers contracting)
Lateral pterygoid Superior/inferior attachment, innervation, and action
Superior head: Greater wing of sphenoid Inferior head: Lateral aspect of lateral pterygoid plate of sphenoid - Superior head: Articular disc & capsule of TMJ Inferior head: Pterygoid fovea of mandible - Nerve to the lateral pterygoid (V3) - Superior head: (considerable current debate/research) activated during clenching of jaw, balancing, protraction Inferior head: depresses the mandible (e.g. opens the mouth)
Medial pterygoid Superior/inferior attachment, innervation, and action
Sphenoid, palatine, and maxillary bones - Mandible (mirrors the masseter m.) - Nerve to the medial pterygoid (V3) - Elevation and protrusion of mandible
What kind of joint is the TMJ? How is it formed?
The TMJ is a compound synovial hinge joint formed by the mandibular fossa of the temporal bone receiving the condyle of the mandible.
What separates the mandibular fossa and the condyle of the mandible? What does it separate them into?
These structures are separated by a fibrocartilaginous articular disc. It separates them into superior and inferior joints
What does the superior joint of the TMJ joint allow for?
protrusion and retraction of the mandible
What does the inferior joint of the TMJ allow for?
elevation and depression of the mandible with minor pivoting actions
What do the muscles of mastication do in regards to the TMJ?
They produce the movements at the TMJ
What is the innervation of the TMJ and the arterial supply?
Afferently innervated by the auriculotemporal n., and supplied by branches of the maxillary and superficial temporal aa.
What major ligaments and other connective tissues limit the range of motion of the temporomandibular joint?
The stylomandibular ligament, lateral (temporomandibular) ligament, sphenomandibular ligament, and retro-articular tissue.
How does the stylomandibular ligament affect the TMJ?
“reinforcing ligament.” does not afford any mechanical constraints to the joint.
What are the attachments of the stylomandibular ligament?
from the styloid process of the temporal bone to the posterior border of the ramus and angle of the mandible.
How does the lateral (temporomandibular) ligament affect the TMJ?
it restricts posterior and lateral movement of the condylar process of the mandible
What are the attachments of the lateral temporomandibular ligament?
it attaches the articular tubercle of the temporal bone to the neck of the condylar process of the mandible. It completely covers the condylar process of the mandible and is intimately related to the articular capsule.
How does the sphenomandibular ligament affect the TMJ?
the sphenomandibular ligament is tense when the TMJ is in an intermediate position (slightly opened)