Exam 1 Flashcards
What are the criteria for optimum functional occlusion?
- Temporal Bone
- Mandible
- Condyles - in their fossae
- Muscles / Ligaments
- Dentition (secondary to role of muscles)
What two bones is the mandibular or glenoid fossa comprised of?
- Temporal
- Mandible
With the articular disc in between
What is the articular eminence a part of and what are the two sections of it?
Temporal bone:
- Posterior Slope
- Inferior Border
What will guide all mandibular movement?
The angle of the articular eminence (steepness or flatness)
What does the synovial cavities provide?
- Joint Lubrication
- Boundary Lubrication from motion
- What limits excessive protrusive movement of the mandible?
- What plays a roleof limiting protrusive movement and lateral mandibular movement of either the right or left side?
- Stylomandibular Ligament
- Sphenomandibular Ligament
What is the position of the Temporomandibular Ligament designed to do?
Limit the pure hinge axis rotational movement of the mandible
The full length of the temporomandibular ligament occurs at no more than ________ of opening, as measured between the ________ of the maxillary and mandibular incisors. –> Which is classifiesd as _________, then commences?
- 15-20 mm
- Incisal Edges
- Translation
Give the characteristics of the Temporomandibular or Articular Disc. (7 things)
- Fibrous connective tissue
- In between mandible and temporal bone
- Somewhat pliable in texture
- Bi-concave shape
- Collateral ligaments attach it to the condyle in a medial and lateral position
- No innvervation
- No vascularization
What are some characteristics of the muscles of mastication?
- Produces smooth movement
- Limited movement by ligamentous structures
- Bone structures are starting, driven by muscles
- Occlusal interferences or premature occlusal contact MAY lead to spasms
- Opening, closing and lateral movements are most notable types of movement (not protrusion)
- 4 main muscles of mastication
- Muscles are the main driver of the craniomandibular apparatus
- Normal function vs parafunctional
What are the Normal vs Parafunctional actions of the Temporalis?
Normal:
- Elevate the mandible
- Retract or retrude the mandible (helps seat condyles)
- Positions mandible to obtain centric relation
Parafunctional:
- Clenching
- Not normally invovled in lateral movements
What are the normal vs parafunctional actions of the Medial Pterygoid?
Normal:
- Elevate the mandible
- Aids in protrusive movement
- Produces mediotrusive movement (PRIMARY muscle to do so)
Parafunctional:
- Minor player in clenching
What are the normal vs parafunctional actions of the Lateral Pterygoid - Inferior Head?
Normal:
- Active during opening movement
- Primary muscle of mastication for protrusive movement
- Primary muscle of mastication for lateral movement
Parafunctional
- Most frequent muscle to exhibit a spasm - from occlusal dysfunction
- Deep in placement - not easily palpated
Describe the actions of BOTH heads of the Lateral Pterygoid muscles.
- Equally significant roles, but different roles in mandibular movement
- When one is active, the other is minimally contracting
- The coordination of normal activity of both heads is very critical - lack of coordination causes breakdown of normal functioning of the craniomandibular apparatus
What are the actions or functions of the Suprahyoid Accessory Muscles?
- Elevate hyoid bone
- Elevate base of tongue
- Depress mandible (when hyoid fixed)
- Assist in stabilizing the cranium and mandbile during normal movements
- Important for control over the pharynx and esophagus during swallowing and speaking