articular-disc of temporomandibular joint

Tmj articular disc anatomy is described for bds students. Disc or meniscus is an important structure in tmj.

2. Articular Disk of TMJ
Presentation By:

Gulalai Bashir
Roll.34
1
st
Year BDS

3. Learning Objectives
Brief introduction of Temporomandibular Joint
Components of TMJ
Articular Disk
Anatomy of Articular Disk
Features of Articular Disk
Brief histology
Functions
Video

4. Recall,
Temporomandibular Joint (TMJ)
Definition:

“ The Temporomandibular joint (TMJ) is formed by the
articulation between the articular tubercle and the anterior
portion of the glenoid fossa of the squamous part of
temporal bone above and the condylar head of the mandible
below”

6. Components of TMJ
TMJ has 6 components:
Mandibular condyle
Joint capsule
Articular Surface of Temporal Bone
Ligaments
Muscular components
Articular disk

7. Articular Disk
Between the two articular surfaces, there is a thin oval plate
made of non-vascular fibrous connective tissue. This intra-
articular disc that is interposed between the articular surfaces
is called the Articular Disc

8. Anatomy of Articular Disc
The articular disc is an oval plate
It is attached circumferentially to
the capsule
The upper surface of the disc is
concavo-convex from anterior to
posterior to fit the shape of the
articular tubercle and mandibular
fossa
The lower surface is concave to fit
the head of the mandible

9. Attachments
Anterior Attachment, it is attached to the tendon of the lateral pterygoid
muscle
Posterior Attachment described as having two layers, one upper and one
lower.
Upper layer: It is connected posteriorly to the anterior face of the post-
glenoid tubercle, the tympanic wall of the temporal bone
Lower layer: attached to the posterior surface of the condyle
It is attached by fibrous bands to the head of the mandible. These bands
ensure that the disc moves forward and backward with the head of the
mandible during protraction and retraction of mandible

11. Features of Articular Disc
Articular Disc divides the joint cavity into
two compartments
The compartment between the condyle
and the disk is called Condylodiskal
The compartment between the temporal
bone and the disk is called Temporodiskal
In sagittal plane it has an Anterior band,
Posterior band and an Intermediate zone
Anterior band is avascular and innervated
Posterior band is highly vascular and
richly innervated

12. Brief histology
In young individuals, the articular disc is composed of dense
fibrous tissue.
The interlacing fibers are straight and tightly packed
The extracellular matrix of the disc is composed mainly of
collagen type I and elastin.
The collagen I type is the predominant component and it is
very important for resisting tensile forces
The elastin is associated with resistance and elasticity and is
responsible for maintaining the shape after deformation.

13. Functions
It functions as a shock absorber
Contributes to the stability of the joint.
Increases the type and range of movements
Reduces the frictional forces between the articular surfaces

14. Movement of TMJ and Articular Disk

15. Thank you!