TMJ

• What is the full name of TMJ?

  Temporomandibular Joint
• What are the types of joints?

  Fibrous, cartilaginous, and synovial
• What does the TMJ articulate with?

  The lower jaw and the cranium
• What is the primary jaw joint during prenatal growth?

  Incudomalleolar articulation
• What type of joint is the TMJ classified as?

  Diarthrosis synovial joint
• What movements can the mandible perform at the TMJ?

  Opening, closing, protrusive, retrusive, lateral
• What are the bony components of the TMJ?

  Glenoid fossa, condylar head, articular eminence
• What are the soft tissue components of the TMJ?

  Articular disk, joint capsule, ligaments
• What is the thickness of the condyle mediolaterally?

  20 mm
• What is the thickness of the condyle anterioposteriorly?

  8-10 mm
• What happens to the disk as we age?

  It can develop cartilage
• What is the role of the fibrous layer covering the condyle?

  It consists of fibroblasts and is avascular
• What is the proliferative zone associated with?

  Formation of condylar cartilage
• What occurs after the production of condylar cartilage?

  Endochondral ossification occurs
• What is the function of the capsule in the TMJ?

  It seals the joint space and provides stability
• What is the temporomandibular ligament's role?

  It restricts distal and inferior movements
• What are the two extrinsic ligaments of the TMJ?

  Stylomandibular and sphenomandibular ligaments
• What is the shape of the TMJ disk?

  Biconcave
• What type of collagen is found in the disk?

  Type I collagen
• How thick is the anterior portion of the disk?

  2 mm
• How thick is the central portion of the disk?

  1 mm
• How thick is the posterior portion of the disk?

  3 mm
• What is found between the two lamellae of the disk?

  A space filled with loose connective tissue
• What supplies the disk with vascular and neural elements?

  The periphery of the disk
• What are the key components of the TMJ anatomy?

  • Bony components:
  • Glenoid fossa
  • Condylar head
  • Articular eminence
  • Soft tissue components:
  • Articular disk
  • Joint capsule
  • Ligaments
• What are the functions of the ligaments associated with the TMJ?

  • Temporomandibular ligament:
  • Provides support
  • Restricts distal and inferior movements
  • Stylomandibular ligament:
  • Connects styloid process to mandible
  • Sphenomandibular ligament:
  • Connects sphenoid spine to mandible
• What are the stages of cartilage development in the TMJ?

  1. Proliferative zone forms condylar cartilage
  2. Chondroblasts create extracellular matrix
  3. Endochondral ossification occurs
  4. Fibrocartilage develops in the mandible
• What are the characteristics of the TMJ disk?

  • Biconcave shape
  • Composed of dense fibrous tissue
  • Thickness varies:
  • Anterior: 2 mm
  • Central: 1 mm
  • Posterior: 3 mm
• What is the significance of the glenoid fossa in TMJ anatomy?

  • Articulates with the condyle
  • Limited by squamotympanic and petrotympanic fissures
  • Anteriorly involved in articulation with articular eminence
• What are the implications of aging on TMJ components?

  • Disk may develop cartilage
  • Proliferative activity ceases by age 20
  • Fibrocartilage in the mandible mineralizes
• What is the role of the articular disk in the TMJ?

  • Divides joint into two compartments
  • Functions as an articular surface
  • Fuses with the capsule anteriorly
• What type of collagen is mentioned in the study material?

  Type I collagen
• What are the thickness measurements of the disk?

  • 2 mm
  • 1 mm
  • 3 mm
• What are the three regions of the disk?

  Anterior, Central, Posterior
• How does the disk appear in coronal sections?

  It is thicker medially
• What happens to the anterior portion of the disk?

  • Fuses with the anterior wall of the capsule
  • Capsule blends with periosteum of anterior slope
  • Merges with periosteum of condyle neck
• What does the posterior portion of the disk divide into?

  Two lamellae
• What are the characteristics of the upper and lower lamellae?

  • Upper lamella: fibrous and elastic tissue
  • Inserts in the squamotympanic fissure
  • Lower lamella: collagen only, blends with periosteum
• What fills the space between the two lamellae?

  Loose, highly vascular connective tissue
• How is the disk supplied with vascular and neural elements?

  Well supplied at periphery, avascular centrally