Articulatio Temporomandibularis - Temporomandibular joint - TMJ
   

Temporomandibular Joint - TMJ -
(Articulatio Temporomandibularis) is synovial joint (has synovial cavity) by structure, diarthrodial joint (allows movements) by function. It is known as ginglymo-arthrodial joint (ginglymo and arthrodial are types of synovial joints).

Ginglymo means- it slides (glides)
Arthrodial meand- it allows rotation

TMJ is a joint between Mandibular Fossa in Temporal Bone and Condylar Process of Mandible;

I. Mandibular Fossa ( Articular Fossa, Fossa Mandibularis) that is an anterior part of the Glenoid Fossa (Fossa Glenoidalis)

Glenoidal Fossa (Fossa Glenoidalis) is composed of:
1.Anterior part: Fossa Mandibularis
2.Middle part: Glaserian Fissure
(Petrotympanic Fissure, Fissura Petrotympanica)
3.Posterior part: which lodges a portion of the parotid gland (Glandula Parotis)

 
Formation of Mandibular fossa:
Superior and Anterior side:
  Articular Eminence (Eminentia Articularis) of the Zygomatic Bone (Os Zygomaticus)- most heavily travelled by mandibular condyle.
Articular Tubercle (Tuberculum Articulare) is an outer end of articular eminence and serves as attachment for TMJ ligament
(external-lateral ligament)
Anterior side (as part of Articular Eminence):
  Pre-Glenoid plane; almost horisontal articular surface( also known as Facies Articularis or Path of Condyles). Together with Occlusal planeare making an Articulation Angle of the TMJ
Posterior side:
  Post-Glenoid Process (Processus Postglenoideus) a sharp ridge positioned between Mandibular fossa and External Acoustic Meatus (Meatus Acusticus Externus)
II. Condylar Process of the Mandible
(Processus Condylaris Mandibulae)
   
     
   
Other parts of Temporomandibular Joint:    
Articular Capsule
(Joint Capsule, Capsula articularis)
  Articular Capsule is a sac that encloses TMJ. Borders:
Superior: Capsule is positioned underneath inferior side of Articular Eminence.
Inferior: Capsule wraps around condyle's neck (Collum Mandibulae)

Articular Disc (Discus articularis)

  It is a fibro-cartilageus disc. It divides synovial cavity of TMJ into:
1. Superior synovial cavity
2. Inferior synovial cavity
Both cavities are filled with synovial fluid, secreted by inner side of articular capsule (clear, viscous fluid).
Attachments of articular disc:

1.Anterior:

a. Anterio-Superior:

indirectly to articular
eminence through
capsule

  b.Anterio-inferior:

to condyl's neck

2.Posterior: a.Posterio-superior: to post-glenoid process
  b. Posterio-inferior: to condyl's neck
Ligaments:
   
   
1. TMJ ligament - External Lateral ligament (Ligamentum lateralis temporomandibulare)
  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
2. Sphenomandibular ligament
(Ligamentum Sphenomandibulare)
  Attachments:
Superior: Spinous process of sphenoid bone
(Processus spinosus os sphenoidale)
Inferior: Mandibular lingula (Lingula mandibulae)
Note: Inferior alveolar nerve (Nervus alveolaris inferor) 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.
3. Stylomandibular ligament
(Ligamentum Stylomandibulare)
 

Attachments:
Superior: Styloid process of temporal bone (Processus styloideus ossis temporalis)
Inferior: Angle of the Mandible (Angulus mandibulae)

 


Addition to the text: Copy of the pages about TMJ from the book "Stomatoloska Protetika"
by Prof.Dr.D.Zelezarov (the first book of Dental Prosthetics written in Macedonian language)
pages 86 and 87
pages 88 and 89
pages 90 and 91

Author of the text: Dr. Boban Fidanoski, DMD - November,2006 Copyright
Bibliography: Gray's Anatomy - Classic Collector's Edition
Sobotta Atlas of Human Anatomy
Stomatoloshka Protetika - Prof.Dr.D.Zelezarov
Images:

Gray's Anatomy - Classic Collector's Edition
Stomatoloshka Protetika - Prof.Dr.D.Zelezarov

Note from the author: This text is a summary of my studies of the TMJ. I published this page on line for education purposes only, primarily of myself and of any other good intentioned visitor of my web site who is involved in Medicine or Dentistry. This is a strictly non-commercial site. Please do contact me if You have any concerns and I will do the nessessary adjustments. Thank You.