Tempro – mandibular Joint Flashcards
what is the origin and insertion of the lateral pterygoid
origin:Upper: greater wing of sphenoid.
Lower: lateral pterygoid plate (lateral surface).
insertion: Depression in the neck of mandible (pterygoid fovea), capsule & articular disc of tempero - mandibular joint (TMJ).
what is the nerve supply of lateral pterygoid
Nerve supply: nerve to lateral pterygoid which is a branch from anterior division of mandibular nerve.
what action does the lateral pterygoid perform
Protrusion of mandible (mouth opener).
Chewing movements with medial pterygoid.
what is the origin and insertion of the medial pterygoid
origin:Deep: Lateral pterygoid plate (medial surface).
Superficial: Tuberosity of maxilla.
insertion:Medial surface of ramus & angle of mandible.
what is the nerve supply of the medial pterygoid
Nerve to medial pterygoid ,branch from trunk of mandibular nerve.
what is the action of the medial pterygoid
Elevation of mandible
Chewing movements of mandible with lateral pterygoid muscle.
what is the origin and insertion of the temporalis
Origin: Floor of the temporal fossa.
Insertion: coronoid process of the mandible.
what is the action of the temporalis
Elevates (vertical fibers, closes mouth) and horizontal fibers retracts the mandible.
what is the nerve supply of the tempporalis
temporal nerves
what is the origin and insertion of the masseter muscle
Origin: Inferior border of the zygomatic arch.
Insertion: Lateral surface of the ramus of the mandible.
what is the action of the masseter muscle
Action: Elevates the mandible (closes the mouth).
what nerve supplies the masseter muscle
Nerve supply: Masseteric nerves.
what structures stabilize the joint
Fibrous capsule.
Lateral ligament.
Spheno - mandibular ligament.
Stylo - mandibular ligaments.
what are the insertion points of the fibrous capsule
Above: to the articular tubercle and the margins of the mandibular fossa.
Below: to the mandibular neck.
what are the insertion points of the lateral temporo- mandibular ligament
Site: lateral to the fibrous capsule.
what is the insertion point of the spheno mandibular ligament
Attachments: above to spine of sphenoid, below to the lingula of the mandible.
what is the insertion points of the stylo mandibular ligament
Attachments: above to the tip of the styloid process, below to the angle and posterior border of the mandible
what kind of cartilage is the articular disk made of
It is a fibrocartilage disc which divides the joint cavity into upper and lower parts.
what is the shape of the articular disc
Shape: its upper surface is concav-convex to fit the articular tubercle and mandibular fossa respectively. Its lower surface is concave for the head of the mandible.
which muscles are used when protrusion of the mandible occurs
Protrusion: Action of lateral pterygoid muscles of both sides simultaneously.
The articular disc glide forwards in upper compartment.
which muscles are used for retraction of the mandible
Retraction: Posterior fibers of the temporalis muscle.
The articular disc glide backwards in upper compartment
which muscles are used for elevation of the mandible
Elevation: Masseter, anterior fibers of temporalis and medial pterygoid muscles.
which muscles are used for depression of the mandible
Depression: Lateral
pterygoids assisted by
myelohyoid and digastric muscles.
what is the blood and nerve supply to this area
Blood Supply: Superficial temporal artery.
Nerve Supply: Auriculo - temporal nerve.
what are the most common ways dislocation of the mandibles occurs
Can occur via a blow to the side of the face, yawning, or taking a large bite.
how does dislocation of the mandible occur
It takes place in forward direction.
The head of the mandible slips into infra - temporal fossa during wide opening of mouth by lateral pterygoid muscle.
what is the process of relocating the mandible
The thumbs are placed upon the lower molars intra- orally, with the fingers wrapped externally around the mandibles.
With the patient positioned with the mandible below the level of the practitioner’s elbows, apply firm, slow, and steady pressure in a downward and posterior direction.
