The document provides a comprehensive overview of the temporomandibular joint (TMJ), detailing its anatomy, structure, and functions. It describes the articular surfaces, ligaments, capsule, and the mechanics of jaw movements, as well as common dysfunctions such as capsulitis and articular disk displacement. The TMJ is essential for functions like talking, chewing, and swallowing and is subject to various inflammatory conditions and mobility issues.

1. BIOMECHANICS:
TMJ
DR.QUAZI HUMA
MPT(NEUROSCIENCES)
ASST PROFESSOR

2. Objectives
Introduction
Structures: Articular Surfaces
Articular Disk Capsule and Ligaments
Upper and Lower Temporomandibular Joints
Function
Dysfunction

3. Introduction
Complex joint and
unique
Condylar hinge-type
of joint
Moves in all direction
Synovial type with no
articular cartilage

4. Structure:
Articular Surfaces
• Proximal segment: Temporal bone
• Distal segment; Condyles of
Mandible
• Trabecular bone with no articular
cartilage
• Fibrocartilage: dense, avascular
collagenous tissue that contains
some cartilaginous cells.

5. • Fibrocartilage - present in
areas, intended to withstand
repeated and high-level stress.
• For example – biting, chewing
• In closed mouth position, the
coronoid process sits under the
zygomatic arch, but it can be
palpated below the arch when
the mouth is open.

6. Articular Disc
• Biconcave
• Thickness- 2 mm anteriorly -3
mm posteriorly-1 mm
• Anterior & posterior portions-
vascular and innervated
• Middle part- Fibrocartilaginous,
force-accepting segment
• Attachment - medial and lateral
poles of the condyle of the
mandible

7.  Bilaminar retrodiskal pad-
1. Superior lamina – elastic in
nature
2. Inferior lamina – inelastic
 The superior lamina allows the
disk to translate anteriorly along
the articular eminence during
mouth opening ,its elastic
properties assist in repositioning
the disk posteriorly during mouth
closing.
 The inferior lamina simply serves
as a tether on the disk, limiting
forward translation

8. Capsule
• TM joint capsule is not as
well defined
• Anterior, medial, and
posterior capsule - quite
thin and loose
• Lateral aspect - stronger
and is reinforced with long
fibers

9. Ligaments
 Primary ligament:
a. TEMPOROMANDIBULAR
LIGAMENT: (suspensory
ligament)
• Outer portion: limits downward
and posterior motion of the
mandible,
• limits rotation of the condyle
during mouth opening.
• Inner portion: Limitation of
posterior translation of the
condyle pro

10. b. STYLOMANDIBULAR LIGAMENT:
• band of deep cervical fascia
• limitation to protrusion of the
the jaw
c.SPHENOMANDIBULAR
LIGAMENT:
• that it serves to suspend the
mandible
• to check the mandible from
excessive forward
translation.

11. Functions of Temporomandibular
Joint.
Most frequently used joints
Talking, chewing, and swallowing
Cartilage covering the articular surfaces is designed to tolerate repeated and high-
level stress.
Musculature is designed to provide both power and intricate control.
Speech requires fine control of the jaw, and the ability to chew requires great
strength.

12. Mandibular
Movements
i. Depression (mouth
opening)
ii. Elevation (mouth closing)
iii. Protrusion (jutting the chin
forward)
iv. Retrusion (sliding the teeth
backward)
v. Lateral deviation (sliding
the teeth to either side)

13. Muscles
• Mandibular depression –
Digastric muscle
• Mandibular elevation –
Temporalis, Masseter
• Protrusion -- bilateral action of
the masseter, medial pterygoid
and lateral pterygoid muscles
• Retrusion -- bilateral action of
the posterior fibers of the
temporalis muscles with
assistance of digastric muscle

14. Dysfunction of TMJ
Inflammatory
conditions
Capsulitis
Synovitis
Rheumatoid Arthrtis
Ank Spond
Capsular
Fibrosis
Overproduction of fibrous
connective tissue
Resulting in fibrosis
Articular disk
displacement
Osseous
Mobility
conditions
Hypermobility
Reciprocal click

16. Thank you!!!!!