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  3. 3. GROSS ANATOMY This is a synovial joint of condylar variety. Articular surfacesA. upper part - a) Articular eminence, b) ant. part of mandibular fossa. B. inferior surface a) head of the mandible.
  4. 4. The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ. The TMJs are one of the only synovial joints in the human body with an articular disc. The name is derived from the two bones which form the joint : the upper temporal bone which is part of the cranium and the lower jaw bone called the mandible.
  5. 5. COMPONENTS There are six main components of the TMJ. Mandibular condyles Articular surface of the temporal bone Capsule Articular disc Ligaments Lateral pterygoid
  6. 6. CAPSULE and ARTICULAR DISC The capsule is a fibrous membrane that surrounds the joint and incorporates the articular eminence. It attaches to the articular eminence, the articular disc and the neck of the mandibular condyle. The articular disc is a fibrous extension of the capsule in between the two bones of the joint. The disc functions as articular surfaces against both the temporal bone and the condyles and divides the joint into two sections, as described in more detail below. It is biconcave in structure and attaches to the condyle medially and laterally.
  7. 7. The anterior portion of the disc splits in the vertical dimension, coincident with the insertion of the superior head of the lateral pterygoid. The posterior portion also splits in the vertical dimension, and the area between the split continues posteriorly and is referred to as the retrodiscal tissue.
  8. 8. LIGAMENTS The ligaments are-the fibrous capsule,the lateral ligament,the sphenomandibular ligament,stylomandibular ligament. The fibrous capsule- attached above to articular tubercle,below to mandible,circumference of mandibular fossa The lateral ligament- attached above to articular tubercle,below to posterolateral aspect of neck of mandible. The sphenomandibular ligament- attached superiorly to spine of sphenoid,inferiorly to is accessory ligament. The Stylomandibular ligament- attached above to lateral styloid process and below to angle of is also accessory.
  9. 9. ARTICULATION The TMJ is a ginglymoarthrodial joint, referring to its dual compartment structure and function (ginglymo-and arthrodial). The condyle articulates with the temporal bone in the mandibular fossa. The mandibular fossa is a concave depression in the squamous portion of the temporal bone.
  10. 10.  There are two TMJs, one on either side, working in unison.  The unique feature of the TMJs is the articular disc. The disc is composed of fibrocartilagenous tissue which is positioned between the two bones that form the joint. The disc divides each joint into two.  The lower joint compartment formed by the mandible and the articular disc is involved in rotational movement-this is the initial movement of the jaw when the mouth opens.  The upper joint compartment formed by the articular disc and the temporal bone is involved in translational movements-this is the secondary gliding motion of the jaw as it is opened widely.
  11. 11. MUSCLE PRODUCING MOVEMENTS Depression- lateral pterygoid mainly Elevation- masster,temporalis,medial petygoid of both sides. Protrusion- lateral and medial pterygoid. Retraction- posterior fibres of temporalis. Lateral or side to side movement eg.turning chin to left side- left lateral pterygoid and right medial pterygoid.
  12. 12. CLINICAL CONSIDERATIONS The most common disorder of the TMJ is disc displacement. The most common cause of TMJ pain is myofascial pain dysfunction syndrome, primarily involving the muscles of mastication. Internal derangements is defined as an abnormal relationship of the disc to any of the other components of the TMJ. Disc displacement is an example of internal derangement. Degenerative joint disease, otherwise known as osteoarthritis is the organic degeneration of the articular surfaces within the TMJ. TMJ pain remains one of the most reliable diagnostic criteria for temporal arthritis.
  13. 13. Diagnosis and Treatment of TMJ TMJ is usually determined by exams, such as xray, MRI and CT scan. If the condition is not serious, a physician will usually recommend several steps: • Resting the jaw joint • Utilizing conventional analgesic pain killers or nonsteroidal anti-inflammatory drugs to alleviate the swelling and tight muscles • Applying heated compresses to the areas • Avoiding strain of the jaw • Avoiding tough foods that require heavy chewing
  14. 14. THANK YOU