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DENT 5315/DH 2215 March 4, 2008. Here comes the Quiz!. Yes!. KEY. Temporomandibular Joint. Dr. Sandra Myers Director, NIDCR’s TIRR TMJ Implant Repository. N ational I nstitute of D ental and C raniofacial R esearch's T MJ I mplant R egistry and R epository. Splints.
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DENT 5315/DH 2215 March 4, 2008 Here comes the Quiz! Yes!
Temporomandibular Joint Dr. Sandra Myers Director, NIDCR’s TIRR TMJ Implant Repository National Institute of Dental and Craniofacial Research's TMJ Implant Registry and Repository
Splints Patient slides deleted to protect patient identity.
Temporomandibular Joint (TMJ) Classification of Joints Temporomandibular Joint
I. Classification of Joints 3 Types of Joints: • Fibrous • Cartilaginous • Synovial
II. Temporomandibular Joint (TMJ) Type of Joint Development Anatomy & Histology D. Biomechanics E. Innervation F. Blood Supply
II. Temporomandibular Joint (TMJ) Type of Joint “synovial sliding-ginglymoid joint” Ginglymoid means: Pertaining to, or resembling, a ginglymus, or hinge joint; ginglyform.
II. Temporomandibular Joint (TMJ) B. Development Association of Meckel’s cartilage with mandible Condylar cartilage appears 12th week
II. Temporomandibular Joint (TMJ) Anatomy & Histology
Condylar Head Bovine Condyle
Condylar Head A - Fibrous layer B - Reserve zone C - Proliferative zone D - Hypertrophic zone E - Calcifying zone F - Bone
Capsule • Functions: • Seals joint space • Passive stability • Synovial lining • Proprioceptive nerve endings Note synovial membrane over villi (arrow):
Articular Disk “Acres of Collagen” Aneural & Avascular
Synovial Membrane • Synovial Fluid: • Liquid environment • Lubrication • Nutrition?
Muscles Muscles of Mastication Difference between unipennate, bipennate & multipennate: Muscles with central tendon Muscle fiber bundles attached to one side, two sides or around multiple central tendons
D. Biomechanics Complex combinations of muscle activity Disk enables complex movements
D. Innervation Movements of synovial joint initiated & effected by muscle coordination. Achieved in part through sensory innervation. Hilton’s Law: The muscles acting on a joint have the samenerve supply as the joint. Therefore: Branches of the mandibular division of the fifth cranial nerve supply the TMJ (auriculotemporal, deep temporal, and masseteric)
D. Innervation 4 Types of nerve endings: 1. Ruffini’s corpuscles (limited to capsule) 2. Pacini’s corpuscles (limited to capsule) 3. Golgi tendon organs (confined to ligament) 4. Free nerve endings (most abundant)
Pacinian Corpuscle “Onion-like encapusulated pressure receptors Surrounding concentric lamellae respond to distortion, generate action potential in unmyelinated fiber in core Bar = 100 microns http://www.kumc.edu/instruction/medicine/anatomy/histoweb/nervous/nervous.htm
Ruffini’s & Golgi Corpuscle Function: Ruffini’s = Posture (proprioception), dynamic and static balance Golgi tendon organ = Static mechanoreception, protection (ligament) Free nerve endings = Pain (nociception) protection (joint) Ruffini’s Corpuscle www.anatomyatlases.org/ MicroscopicAnatomy/Section06/Section06.shtml