Temporomandibular Joint. Dr Noman ullah wazir

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2 Temporomandibular Joint Dr Noman ullah wazir

3 Type of Joint TMJ is a Synovial joint between : The condylar head of the mandible. The mandibular fossa of squamous part of temporal bone. The joint cavity is filled with Synovial fluid. It is further classified as ginglymus ( sliding Hinge) joint.

4 TMJ SYNONYMS Craniomandibular articulation Ginglymus joint ( By function) allows Gliding movement Diarthrodial joint (By function) allows rotational movements Mandibular joint Synovial joint ( By structure) contains Synovial cavity

5 TMJ It functions bilaterally in union. The articular disc is movable during joint movements. The articular surfaces are covered by fibro cartilage not hyaline cartilage. The fibro cartilage is considered as a growth center, which contributes to the over all growth of the mandible.

6 STRUCTURES INVOLVED IN TMJ The Articular Eminence Articular fossa Condyle Capsule Ligaments Synovial linings Articular Disc Muscles

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8 ARTICULAR EMINENCE Is a bony eminence present at the inferior aspect of the zygomatic process of the temporal bone The lateral aspect of articular eminence is often referred as articular tubercle Two terms can be used synonymously

9 ARTICULAR FOSSA It is a depression anterior to external acustic meatus. It is limited anteriorly by articular eminence and posteriorly by posterior glenoid tubercle or process.

10 ATTACHMENTS OF ARTICULAR DISC 1.Anterior: a. Anterio-Superior: Indirectly to articular eminence through capsule. b. Anterio-Inferior : To condyl's neck of mandible. 2.Posterior: a. Posterio-superior : To post-glenoid process b. Posterio-inferior : To condyl's neck of mandible.

11 CONDYLE Condyle comprises of head and neck. It is covered by a thick fibrous connective tissue containing fibroblasts. The fibrocartilage is found in condyles and articular eminence. The presence of fibrocartilage helps in adapting stress.

12 CAPSULE The fibrous capsule is a loose envelope which defines the anatomical and functional boundaries of the joint The joint (capsule) is attached : Anteriorly- almost 4mm anterior to the apex of the articular eminence. Posteriorly- to the anterior lip of the petrotympanic fissure. Superiorly- to the margins of the articular fossa Inferiorly - to the neck of condyle medially and laterally.

13 TMJ ligaments External Lateral ligament Short ligament, positioned on the external lateral side of TMJ Attachments: Superior : lateral surface of articular eminence Inferior : latero-posterior part of condyle's neck

14 External lateral ligament

15 SAPHENOMANDIBULAR LIGAMENT Attachments: Superior: Spinous process of sphenoid bone Inferior: Mandibular lingula (medial surface of ramus of mandible) Note: Inferior alveolar nerve is located in the space between mandibular ramus and sphenomandibular ligament (it descends towards mandibular foramen).this is an important landmark for administration of inferor alveolar anesthetic block.

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17 STYLOMANDIBULAR LIGAMENT Stylomandibular ligament (Ligamentum Stylomandibulare) Attachments: Superior: Styloid process of temporal bone Inferior: Angle of the Mandible

18 Stylomandibular ligament

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20 SYNOVIAL LINING The capsule is consist of two layers: 1. Outer fibrous layer. 2. Inner Synovial lining. The synovial lining produces synovial fluid. Increased amount of fluid indicates pathology.

21 ARTICULAR DISC Articular disc is thin in front and thick behind. It is quite flexible. It consists of dense avascular connective tissue. It is divided into anterior, posterior and intermediate zones. It fits over the condyles like a cap.

22 When the mandible is at rest the ideal articular disc position in the articular fossa is with the posterior band at about 12 o clock position Increases the stability of the joint and protects articular surfaces Absorbs the shock and helps in joint movement

23 MUSCLES ACTING ON THE TMJ Movements of the TMJ are chiefly from the action of the muscles of mastication. The temporalis, masseter, and medial pterygoid produce biting movements. The lateral pterygoid muscles protrude the mandible with the help from the medial pterygoid muscles and retruded largely by the posterior fibres of the temporalis muscle.

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26 INNERVATION OF THE JOINT The nerves that innervate the joint are: 1. Auriculotemporal nerve 2. Masseteric nerve 3. Posterior deep temporal nerve All are derived from mandibular nerve

27 Post deep temporal nerve Massetric nerve Auriculotemporal nerve

28 Blood Supply of TMJ Blood supply is from the: Maxillary and Superficial temporal branches of the external carotid artery

29 MOVEMENTS OF TMJ The 2 type of movements which can occur in TMJ are; 1. Hinging movement ( takes place between condyle and the disc) 2. Gliding movement ( forward and backward movement mainly takes place between the disc and temporal surface)

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31 TMJ SYNDROME When this joint is injured or damaged, it can lead to a localized pain disorder called temporomandibular joint (TMJ) syndrome.

32 Causes of temporomandibular joint (TMJ) syndrome include injury to the teeth or jaw, misalignment of the teeth or jaw, teeth grinding, poor posture, stress, arthritis, and gum chewing.

33 Signs and symptoms of temporomandibular joint (TMJ) syndrome include pain in the jaw joint, jaw clicking and popping, ear pain/earache, popping sounds in ears, headaches, stiff or sore jaw muscles, pain in the temple area, or locking of the jaw joint.

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