TMJ Flashcards
Temporomandibular Joint (TMJ)
The joint where the mandible articulates with
the base of the cranium
what fits into the TMJ
condyle of the mandible
Squamous part of the temporal bone (3)
- MANDIBULAR FOSSA
- GLENOID FOSSA
- ARTICULAR FOSSA
what separates the TMJ and cranium?
articular disk
mediolateral length of condyle
15-20 mm
anteroposterior width of condyle
8-10 mm
poles of condyle (2)
medial
lateral
which of the following muscles of mastication inserts into the articular disc?
lateral pterygoid
Compound Joint (2)
–more than three bones
–condyle, temporal, articular disc
Complex Joint (1)
–allows more than one type of movement
Ginglymoarthrodial Joint (3)
–Ginglymoid joint implies
–Arthrodial joint implies
–Ginglymoarthrodial implies
hinging movement permitted
gliding movement
both hinging and gliding movements
Synovial Joint (1)
–Contains synovial fluid
arthrodial joint movement
translational movement
gingylmus joint movement
rotational
what muscle is mainly responsible for protrucing the mandible?
lateral pterygoid
ginglymo-arthrodial joint movement
rotational and translational movement
which of the following muscles retrudes the mandible
temporalis
Articular Disc is made of
dense fibrous connective tissue
shape of Articular Disc (2)
–Concave on the inferior part
–Concavo-convex on the superior part
Articular Disc innervation is (3)
Non-innervated and avascular
–Poor reparative capacity
is the articular disc flexible?
somewhat, yes
Articular Disc is divided into three sections:
• Anterior Zone
• Middle or Intermediate Zone (thinnest)
• Posterior (thickest)
Posterior > Anterior > Middle
Articular surface of the condyle functions on the — zone of the disc
intermediate
Disc is divided into
medial and lateral parts
Disc is thicker …
medially than laterally
Discal/Collateral Ligaments attach the disc
to the
medial and lateral poles of the
condyle and to the surrounding capsule
Articular Zone:
Most superficial layer. Unlike other
synovial joints, this layer is made of dense fibrous
connective tissue rather than hyaline cartilage; less
susceptible to aging and better ability to repair
Proliferative Zone:
Contains undifferentiated
mesenchymal cells and is responsible for
proliferation of articular cartilage in response to
loads
Fibrocartilaginous Zone:
3D network of collagen
offering resistance to lateral and compressive forces
Calcified Zone:
Made up of chrondrocytes and
chrondoblasts. Active site for bone remodeling.
Synovial Joint
• All areas of the joint not involved in
articulation (internal surfaces of the cavities)
are covered with
specialized endothelial cells that form the synovial lining
Synovial Joint produces
Synovial fluid (provides metabolic requirements and lubrication)
Synovial Fluid acts as a
lubricant
–Boundary lubrication:
–Weeping lubrication:
movement of fluid from one
area of the joint cavity to another, prevents
friction
articular surfaces absorb
some of the fluid, increased absorption during
function, metabolic exchange
INNERVATION and VASCULARIZATION (2)
• Mandibular branches of the trigeminal nerve (auriculotemporal and masseteric nerves) • Superficial temporal artery mainly, which is a branch of the external carotid artery
DISC ATTACHMENTS (3)
• Posteriorly • Anteriorly • The disc is also attached to the capsular ligament not only anteriorly, but also posteriorly, medially and laterally.
Posterior attachments of the disc (2)
- Superior Retrodiscal Lamina
* Inferior Retrodiscal Lamina
Superior Retrodiscal Lamina (4)
– Attaches the articular disc to the tympanic plate
– Connective tissue
– Lots of elastic fibers
– Stretches as joint is moved forward
Inferior Retrodiscal Lamina (2)
– Collagenous attachment (not elastic)
– Attaches the posterior of disc to the posterior margin of the articular surface of the condyle
Anterior attachments of the disc (collagenous) (3)
- Superior head of the lateral pterygoid muscle (tendinous)
- Superior anterior attachment
- Inferior anterior attachment
Superior anterior attachment (2)
–to the Capsular Ligament
–to the anterior margin of the articular surface of the temporal bone
skipped
Inferior anterior attachment (2)
–to the Capsular ligament
–to anterior margin of the articular surface of the condyle
Superior Joint Cavity
Bordered by the (2)
–glenoid fossa
–superior aspect of the disc
Inferior Joint cavity Bordered by (2)
–inferior aspect of the disc
–superior aspect of the condyle
Rotation occurs in the — joint compartment
inferior
Translation in the — joint compartment
superior
which of the following is a correct statement?
the mediolateral length of the condyle is…
15-20 mm
Functional ligaments (3)
–Collateral/Discal ligaments
–Capsular ligament
–Temporomandibular ligament
Accessory ligaments (2)
–Sphenomandibular ligament
–Stylomandibular ligament
Capsular Ligament /Joint Capsule
Ligament that surrounds the joint like a curtain
Capsular Ligament /Joint Capsule is attached to the (2)
he base of the skull and the condyle
Capsular Ligament /Joint Capsule is attached at the — of the articular parts
periphery
Capsular Ligament /Joint Capsule is also attached t the disc (2)
medially and laterally
Capsular Ligament /Joint Capsule retains..
synovial fluid
Temporomandibular Ligament
Thickening of the capsular ligament on the lateral
aspect
skipped
Temporomandibular Ligament extends from
articular tubercle and zygomatic process to the lateral pole and neck of the condyle,
and the disk
2 parts of Temporomandibular Ligament
outer oblique
inner horizontal
Function of the Outer Oblique part (2)
–Prevents over rotation of the mandible
–Causes translation of the mandible after 20-25
mm opening
Function of the Inner Horizontal part (2)
–Limits posterior movement onto the highly
innervated retrodiscal tissue (PAIN)
–Prevents excessive overextension of the lateral
pterygoid muscle
Sphenomandibular Ligament arises from the
sphenoid bone
Sphenomandibular Ligament inserts onto the
medial surface of the ramus of the mandible called the lingula
Sphenomandibular Ligament function
no known function in limiting mandibular movement
Stylomandibular movement arises from
styloid process
Stylomandibular movement inserts into
posterior border on the ramus of the mandible
Stylomandibular movement function
limits excessive protrusive movement of the mandible
sphenomandibular ligament
o:
I:
o: angular spine of sphenoid bone
I: mandibular lingula
sylomandibular ligament
o:
I:
o: soloed process
I: angle of mandible
the tympanic plate is part of which bone?
temporal
the external auditory meatus is located in which bone?
temporal