Anatomy of the Masticatory Structures

Question 1

Temporomandibular Joint (TMJ)
 The TMJ is a …
 The — move synchronously

Answer 1

ginglymoarthrodial joint
with hinging or rotation movements in one plane
(ginglymoid joint) & gliding or translation movements
in another plane (arthrodial joint)
condyles/jaw

Question 2

Temporomandibular Joint
 Two of the most complex joints
in the body.
 Articulation between the (2)
 The mandibular condyle fits into
the —
 The — separates these
2 bones from direct contact

Answer 2

cranium
& mandible.
mandibular (glenoid) fossa
articular disc

Question 3

TMJ Capsule

Answer 3

 A fibrous capsule contains
the synovial fluid, limits its
motion and maintains the
relationship between the joint
components.

Question 4

Temporomandibular Joint (TMJ)
 Is a Synovial joint
 Synovial fluid(synovia) transports …
 Synovial fluid is secreted by the membrane lining the
synovial joint and there is approximately — in each
compartment of the joint spaces
 Articular Disc separates the condyle & mandibular
fossa from direct contact & divides joint into …

Answer 4

nutrients to & waste
products from the articular surfaces & lubricates joint
1cc
superior
and inferior joint spaces

Question 5

Functions of Disc
(3)

Answer 5

1. Distributes loading forces
2. Decreases wear
3. Stabilizes condylar movement

Question 6

Disc
1. Articular portion is composed of …
2. Has some ability to — itself
3. Is devoid of …
4. The posterior attachment of the disc is highly …

Answer 6

dense fibrous
connective tissue NOT cartilage
repair
nerves or blood vessels in the
intermediate zone which articulates with the
superior aspect of the condyle during translation
vascularized and innervated

Question 7

Histology of the TMJ
A. Disc
(3)

Answer 7

1. Dense, fibrous connective tissue
2. Non-vascular in center
3. Non-innervated in center

Question 8

Histology of the TMJ
B. Posterior attachment (Retrodiscal Tissue)
(2)

Answer 8

1. Loose, vascular, connective tissue (contains
   collagen fibers, adipose tissue, elastin, arteries & a
   venous plexus)
2. Richly innervated by auriculotemporal nerve

Question 9

Unique features of the TMJ
 The articulating surfaces are lined with

Answer 9

dense
fibrocartilage (instead of hyaline cartilage) which
allows for a greater ability to heal

Question 10

Articular Cartilage
 A thin layer of
 Plays an important role as a — during
function.
 Research suggests that compressive loading is highest
in the — region of the condyle (1).
 Composed of —

Answer 10

cartilage covers the articulating surface
of the bones.
stress absorber
anteromedial
cells and extracellular matrix (i.e.
collagens & proteoglycans).

Question 11

TMJ Anatomy: Discal ligaments
 Allow the disc to move in — direction
during condylar translation.
 Discal ligaments may become inflamed & painful
because they are —
Articular disc
Capsular ligament Medial discal ligament

Answer 11

anterior-posterior
vascularized and innervated.

Question 12

TMJ Anatomy: Capsular ligaments
 Attach the disc to the condyle on the —
surfaces
 Allow the disc to — on the condyle during condylar
translation

Answer 12

medial & lateral
rotate

Question 13

— passively limit joint movement

Answer 13

Ligaments

Question 14

Vascular Supply
(2)

Answer 14

1. Superficial temporal artery
2. Maxillary artery

Question 15

1. Superficial temporal artery
   (1)
2. Maxillary artery
   (3)

Answer 15

a) Transverse facial

a) Deep auricular
b) Masseteric
c) Posterior deep temporal

Question 16

Nerve Supply
(2)

Answer 16

 Auriculotemporal (V3) nerve
 Masseteric nerve

Question 17

Masticatory Muscles
(5)

Answer 17

1. Masseter
2. Medial pterygoid
3. Temporalis
4. Lateral pterygoid –
5. Digastric muscle –

Question 18

2. Medial pterygoid

Answer 18

Elevate (close) the mandible

Question 19

4. Lateral pterygoid –

Answer 19

assists in protrusion & lateral movements
(inferior head) & stabilizes the disc/condyle complex (superior head)

Question 20

5. Digastric muscle –

Answer 20

assists in depression (mouth opening) &
retrusion

Question 21

Masticatory Muscles
1. Skeletal muscles which provide movement of the
TMJ’s
2. Functional behaviors: (3)
3. Nonfunctional (parafunctional) behaviors: (3)
4. Innervation: (1)

Answer 21

talking, chewing, and
swallowing

bruxism,
clenching, or empty-mouth chewing movements (i.e.
tardive dyskinesia, orofacial dystonias)

V3 (Mandibular Nerve)

Question 22

SUPERFICIAL MASSETER:

Answer 22

Elevates the mandible (closes
the jaw)

Question 23

DEEP MASSETER:

Answer 23

Retrudes the mandible

Question 24

Temporalis Muscle
ACTIONS:
(3)

Answer 24

*Closes the jaw
*Retrudes the jaw
(with posterior and
middle fibers)
*Deviates the jaw
to the same side
(if unilaterally
contracting)

Question 25

Medial Pterygoid Muscle
ACTIONS:
(3)

Answer 25

*Deviates jaw to opposite side
(if contracting unilaterally)
*Helps to
elevate the mandible
(closes jaw) in concert with
masseter & temporalis muscles
(if contracting bilaterally)
*Assists the lateral pterygoid inprotrusion

Question 26

Lateral Pterygoid Muscle
Superior division:
(1)
Inferior division:
(2)

Answer 26

*Pulls disc forward and
check-reins its backward
movement & assists in
closing jaw

*Protrudes and depresses
the mandible (opens jaw)
*Deviates jaw to opposite
side

Question 27

Digastric Muscle Actions
(2)

Answer 27

 Depresses (opens) &
 Retrudes the mandible.

Question 28

Temporomandibular Disorders
(TMD)
A collective term that includes a number of clinical
problems involving the masticatory muscles, TMJ &
associated structures which are identified as the major
cause of non-dental pain in the orofacial region:
(3)

Answer 28

1. Musculoskeletal Disorders
2. Articular Disc Disorders
3. Inflammatory & non-inflammatory Disorders