The temporomandibular joint (TMJ) connects the temporal bone of the skull to the mandible. It contains an articular disc that separates the joint into upper and lower compartments. The condyle of the mandible articulates with the mandibular fossa in the lower compartment and glides forward in the upper compartment. The articular disc allows for this movement and is innervated by the auriculotemporal and masseteric nerves. Disorders of the TMJ can cause sounds, locking, or pain and are sometimes caused by bruxism or arthritis.
2. Anatomy
Joint is the joining together of two bones
Temporomandibular joint (TMJ) is articulating
joint between temporal bone (skull) and mandible
(lower jaw)
Bilateral movement of right and left sides
interrelated and function as single unit
The articular disc separates the joint into upper and
lower compartments
3. Anatomy
The condoyle of the mandible articulates with the
mandibular (glenoid) fossa
Location is the posterior slope of the articular
eminence and anterior portion of the mandibular
fossa
Does not fit into the center of the mandibular fossa
but rests near the articular (eminence) tubercle
Articular disc (meniscus) rests between them
5. Anatomy
The articular disc is a pad of dense fibrous connective
tissue that is thickest at the posterior ends, thinnest in
the middle, and thicker again at the anterior end.
It separates the TMJ into upper and lower joint
compartments.
Laterally and medially, the disc is attached to the condyle
itself, so that whenever the condyle glides forward and
backward the disc moves with it.
6. Anatomy
The condyle and articular eminence are covered
by dense connective tissue
Contains no blood vessels or nerves
Nourished and lubricated by synovial fluid
Joint is covered by a thick fibrous capsule
The articular disc and capsule are connected by a
retrodiscal pad
A pad of loose connective tissue that allows for
anterior movement of the joint
8. Nerve and Blood Supply
Innervation supplied by two nerves
Auriculotemporal and Masseteric
Branches of mandibular nerve (V3)
Blood supply provided by branches of
superficial temporal and maxillary arteries
9. Movement
Two types of movement in TMJ
Hinge motion occurs in lower joint compartment
between the disc and the condoyle
Anterior gliding takes place in the upper joint
compartment between the disc and the temporal
bone
The lateral pterygoid muscle causes the forward
movement
10. Movement
Closing of the mouth is
accomplished by the lateral
pterygoid muscle, which
controls posterior movement
of disc
11. Clinical Considerations
An Internal Derangement occurs when the disc
becomes stuck or displaced.
As the condyle rotates and translates forward down
the slope of the articular eminence, the disc should
stay interposed between these bones.
If it becomes displaced or stuck, sounds of clicking,
popping or crepitus (crunching) may result.
12. Clinical Concerns
Catching or locking of the jaw, subluxation
The condoyle is displaced anteriorly and cannot be
returned voluntarily to normal position
Temporomandibular disorder (TMD), characterized
by muscle soreness
Bruxism (teeth grinding) from stress or tension are
usual causes
13. Clinical Concerns
Inflammation - arthritis may result from
wear or tear within the joint
Can also be a result of systemic disease
like rheumatoid arthritis
Cortisone is used to alleviate the pain of
arthritis