Questions and Answers
What type of joint is the Temporo-mandibular joint (TMJ)?
Which of the following is NOT a synonym for the Temporo-mandibular joint?
How many TMJs are present in the human body?
What type of movement does the TMJ provide in one plane?
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What is the name of the bone that forms the articulating surface of the TMJ?
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What is the term for the joint that provides both hinging and sliding movements?
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What is the classification of the TMJ based on its structure?
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How many articular surfaces are present in the TMJ?
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What is the function of the articular disc in the temporomandibular joint?
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What is the purpose of the TMJ ligaments?
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What is the main function of the collateral ligament?
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What is the composition of the TMJ capsule?
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What is the function of the sphenomandibular ligament?
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What is the anatomical basis of the articular surface of the temporal bone?
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What is the shape of the TMJ capsule?
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What is the function of the articular tubercle or postglenoid tubercle?
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What is the shape of the glenoid fossa?
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What is the function of the lateral/TMJ ligament?
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What is the purpose of the stylomandibular ligament?
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What is the characteristic of the articular part of the condyle?
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What is the characteristic of the articular disc?
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What is the characteristic of the upper joint space?
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What is the posterior bilaminar zone characterized by?
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What are the three general regions of the articular disc as viewed from the lateral perspective?
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Study Notes
Temporo-mandibular Articulation
- The temporo-mandibular joint (TMJ) is a diarthrodial, freely movable articulation between the condyle of the mandible and squamous part of the temporal bone.
Classification of Joints
- Fibrous joints: two bones connected by fibrous tissue
- Cartilagenous joints: two bones connected by cartilagenous or bone tissue
- Synovial joints: two bones united and surrounded by a capsule that creates a joint cavity and permits significant movement
TMJ Characteristics
- Bilateral condylar variety of synovial joint
- Anatomically, it is a diarthrodial joint, which is a discontinuous articulation of two bones
- Provides a hinging or rotation movement in one plane, thus can be considered as ginglymoid joint
- Provides a sliding movement, thus called as arthrodial joint
- Therefore, it can be called as GINGLYMOARTHRODIAL joint
Anatomy of TMJ
- Gross Anatomy:
- Number: present on each side, 2 in number
- Type: synovial joint
- Bones involved:
- Glenoid fossa of temporal bone
- Condyle of the mandible
- Articulatory system:
- Upper articular surface: temporal bone
- Lower articular surface: mandibular condyle
- Roof: 2 parts of temporal bone
- Floor: superior surface of disc
- Articulating surface of mandibular condyle
Articular Surfaces
- Articular surface of temporal bone (Cranial component):
- Includes three components:
- Glenoid fossa
- Postglenoid tubercle
- Articular eminence
- Includes three components:
- Articular surface of mandibular condyle (Mandibular component):
- Ovoid condylar process (head) with narrow mandibular neck
- Condyle tends to be rounded mediolaterally and convex anteroposteriorly
- Broad laterally and narrow medially
- Covered by fibrocartilage
Articular Disc
- Morphology:
- Derived from mesoderm of 1st pharyngeal arch
- Biconcave sagitally, thicker anteriorly and thinner posteriorly, oval, avascular, and non-innervated in the middle
- Can be divided into 3 general regions:
- Anterior band (2mm)
- Central intermediate zone (1mm)
- Posterior band (3 mm)
- Upper joint space is larger (1.2ml)
- Lower joint space is smaller (0.9 ml)
Posterior Disc Attachment/Bilaminar Zone
- Posteriorly: posterior bilaminar zone with rich neurovascular supply
- Disc divides into:
- Inferior lamella
- Superior lamella
Function of Articular Disc
- Condyle and the temporal bone do not fit together in the absence of the disk
- Stabilization of the temporomandibular joint
- The articular disc may reduce wear
TMJ Ligaments
- Functional ligaments (True Ligaments):
- Collateral ligament
- Capsular ligament
- Lateral ligament
- Accessory ligaments:
- Sphenomandibular ligament (remnants of Meckel’s cartilage)
- Stylomandibular ligament (thick band of deep cervical fascia that limits excessive protrusion of the mandible)
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Description
Explore the definition, classification, and features of the temporomandibular articulation, also known as the jaw joint. Learn about the condyle of the mandible and squamous part of the temporal bone.
