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Temporomandibular joint [ TMJ ] - Coggle Diagram
Temporomandibular joint [ TMJ ]
Definition
Is a joint on each side of head that allows movement of MANDIBLE for speech and mastication.
Tow bones
Temporal bone المنطقه التي فيها الاذن
Mandible bone التي هي عظمة الفك
Made up
Glenoid fossa ( MANDIBULAR FOSSA )
Area of the TEMPORAL BONE where CONDYLES of mandible articulate with skull.
Articular eminence
Raised portion of the TEMPORAL BONE just ( anterior to glenoid fossa )
Condyloid process
of MANDIBLE lies in the GLENOID FOSSA.
Types of movement
Hinge action
First phase in mouth opening
Glinding movement
allows the lower jaw to move forward or backwards.
Disorders
Clenching
is holding the teeth tightly together for prolonged periods.
Bruxism
is habitual grinding of the teeth especially at night.
TMD is a complex disorder that involves many factors, such as stress, clenching and bruxism
can caused by trauma to jow, system diseases such as OSTEOARTHRITIS or wear as result of aging
Categories of Temporomandibular Disorders TMDs
Acute masticatory muscle complaints
Characterisation by muscle inflammation, muscle spasms, and protective muscle splinting.
Articular disc derangement
allows smooth movement of joint. It may displaces or damaged.
or clicking sound, limited ability to open mouth and other symptoms associated with TMDs.
Extrinsic trauma
May involve dislocation of the joint, fracture of the bone and internal derangement of joint.
it form external causes
Joint diseases
Degenerative and inflammatory form of arthritis my severely damage joint.
Chronic mandibular hypo-mobility
Hypo-mobility -> limited ability to move. In mandible, this may be influenced by damage to joint ( nosy portions or articular capsules), contracture( shortening) of muscles of mastication or damage to articular disc.
Capsular ligament
Fibrous joint capsule completely encloses the TMJ.
The capsule wraps around the MARGIN of TEMPORAL BONES articular eminence and articular fossa superiorly. Inferiorly, the capsule wraps around the circumference of the MANDIBULAR CONDYLE , including the CONDYLAR NECK.
Articular Space
area between the capsular ligament and the surfaces of glenoid fossa and condyle
Articular disc
also known as the meniscus. Is cushion of dense, specialized connective tissue that divides articular space into upper and lower compartment
These compartments are filled with synovial fluid, which helps lubricate the joint fills the synovial cavities
Symptoms
one reason TMD is difficult tho diagnose is that symptom are so varied .
pain , joint sounds and limitations in movement occur most often.