TMJ and MoM

ginglymoarthrodial joint
synovial joint

Joints of the TMJ (x2)

ginglymoid joint - hinging movement
arthrodial joint - gliding movement

TOPIC: TMJ

what are joints under the ginglymoarthrodial joint and what are their movements? (x2)

temporomandibular joint

what is formed by condylar process of the mandible and mandibular fossa and articular tubercle of temporal bone and it is the only movable joint between skull bones (one of the most complex joint in the body)

synovial fluid

TOPIC: TMJ

what fluid serves as a lubricant between auricular surface during function

Condylar process of the mandible
Mandibular fossa of temporal bone 
Articular tubercle of temporal bone

parts of the TMJ

Articular Disc
Articular Capsule
Lateral Ligament
Spenomandibular Ligament
Stylomandibular Ligament

what are the anatomical components of the TMJ

nonvascular
metabolic
tissues

Synovial Joint:

Articular surfaces are ______, hence it acts as a medium for providing ______ requirements of the ______

Articular disc

TOPIC: TMJ

Composed of FIBROCARTILAGE which separates the synovial cavity

depression/elevation
protraction/retraction
rotation

TOPIC: Anatomical components of the TMJ
Auricular Disc:

INFERIOR: Helps with ______ / ______
SUPERIOR: _______ / _______, lateral displacement, slight ______

articular capsule

TOPIC: Anatomical components of the TMJ

what is thin, fairly loose enveloped around the circumference of the joint

lateral ligament

TOPIC: Anatomical components of the TMJ

what is found in front of the articular capsule and are two short bands on the lateral surface of the articular capsule?

sphenomandibular ligament

TOPIC: Anatomical components of the TMJ

what band extends inferiorly and anteriorly from the spine of the sphenoid bone to the ramus of the mandible?

strengthen

TOPIC: Anatomical components of the TMJ

Sphenomandibular joint does NOT contribute significantly to the _______ of the joint

stylomandibular ligament

TOPIC: Anatomical components of the TMJ

what separates the parotid gland from the submandibular gland

mandible

TOPIC: Anatomical components of the TMJ

Stylomandibular ligament limits the movement of the _____ at the temporomandibular joint

styloid process
ramus

Stylomandibular ligament is located from the _______ ________ of the temporal bone to the inferior and posterior border of the _____ of the mandible

elevation and depression
protrusion and retrusion
side to side chewing

what are the movement of the muscle of mastication?

• hinge =

• condyloid =

• sliding/arthrodial =

masseter
temporalis
medial pterygoid (internal)
lateral pterygoid (external)

what are the 4 muscle of mastication?

Elevation (bilateral)
Ipsilateral Excursion (unilateral)
Protrusion (bilateral superficial head)

TOPIC: MOM
what are the actions of masseter?

• superficial head: ??

Retrusion (bilateral)

TOPIC: MOM
what are the actions of masseter?

• Deep head: ??

Elevation (Bilateral)
Ipislateral excursion (Unilateral)
Retrusion (Bilateral)

TOPIC: MOM
what are the actions of temporalis?

Elevation (Bilateral)
Protrusion (Bilateral)
Contralateral excursion (Unilateral)

TOPIC: MOM
what are the actions of medial pterygoid?

Depression (Bilateral)
Protrusion (Bilateral)
Contralateral excursion (Unilateral)

TOPIC: MOM
what are the actions of lateral pterygoid?

• Inferior head: ??

Elevation (particularly during power stroke)

TOPIC: MOM
what are the actions of lateral pterygoid?

• Superior head: ??

suprahyoid and infrahyoid of the neck

what are the accessory muscles of the mastication?

masseter

Topic: 4 muscle of mastication

what muscle covers most of the lateral aspects of the ramus of the mandible and is a small quadrilateral muscle

temporalis

Topic: 4 muscle of mastication

what muscle covers strong membranous sheet of fascia and is FAN-SHAPED

medial pterygoid (internal)

Topic: 4 muscle of mastication

→ The medial and the lateral pterygoids are the OCCUPANTS OF THE INFRATEMPORAL FOSSA

→ Almost a MIRROR-LIKE IMAGE of the masseter muscle and rhomboidal that runs practically in the same direction on the inner surface of the mandible.

lateral pterygoid (external)

Topic: 4 muscle of mastication

→ Almost triangular in shape
→ has two distinct heads which are inferior and superior head, each with contrasting functions
→ only muscle of the MoM to occupy primarily a horizontal position

move the mandible
secure then stabilize the mandibular position
determine the direction of mandibular movements

what are the generalized function of MoM

depression
protrusion
retrusion
right lateral excursion
left lateral excursion

Topic: MoM

what are the actions of muscle (x5)

helps depress the mandible

what is the functions of the accessory muscle