W4: TMJ/Muscles of Mastication Flashcards
What two bones make up the TMJ
Articulation between the squamous portion of the temporal bone and the condyle of the Md
List the five things that make the ‘TMJ’
- Squamous portion of the temporal bone
- Articular disc
- Condyle of the Md
- Capsule
- Ligaments
What covers the articular surface of the squamous part of temporal bone.
Describe the relations
What do the Md condyles articulate with?
Describe the shape, surface and load bearing area’s of the Md condyles
What is the articular disc comprised of?
List its attachments and various parts
List and describe the three components of the posterior attachment complex and its role
Attaches the disc to the bone and provides nourishment and innervation
List and describe the ligaments of the TMJ
TMJ Capsule: Completely encloses the TMJ. Made of Fibrous connective tissue Lined by highly vascular synovial membrane, highly innervated
Collateral (discal) ligament: connects the disc to the condyle; collagen (non strechy)
* Medial
* Lateral
Temporomandibular (lateral) ligament: Thickened lateral aspect of the capsule. Prevents lateral and posterior displacement of the condyle
Stylomandibular: From the styloid process to the angle of the mandible - limits anterior protrusion
Sphenomandibular* From the spine of sphenoidto the lingula mandible - maintains the same amount of pressure during opening and closing
Describe the origin, insertion, direction of fibres, action, innervation and blood supply of the Temporalis
Describe the shape, location, action, innervation and blood supply of the Masseter
Action: elevates, protrudes, aids in lateral excursion
Describe the two heads of the masseter, listing their origin, insertion, direction of fibres and action
Superficial head (larger)
* Origin: anterior 2/3 of zygomatic arch
* Insertion: angle of Md & inferior and lateral parts of ramus
* Direction of fibres-posteroinferiorly
* Action- elevation & protrusion
Deep head (smaller)
* Origin- medial border of the posterior 1/3 of zygomatic arch
* Insertion- coronoid process & superolateral surface of ramus
* Direction of fibres- vertical
* Action- elevation & retraction (from the protruded position)
Where are the landmarks for the pterygoids?
Describe the shape, location, action, innervation and blood supply of the Medial pterygoid
Describe the two heads of the medial pterygoid, listing their origin and insertion
What three muscles create a ‘sling’ around the angle of the Md
Describe the shape, location, action, innervation and blood supply of the Lateral pterygoid
Describe the two heads of the lateral pterygoid, listing their origin and insertion
