Chapter 14- Temporomandibular Joint

the ? ligament located anteriorly, it attaches on the mandibular condyle and disk, and then runs superiorly to the articular tubercle of the temporal bone. It limits downward, posterior, and lateral motions of the mandible

lateral ligament also known as the temporomandibular ligament

the ? is shaped somewhat like a horseshoe and articulates with the temporal bone on each side of the cranium. It consists of a body and two upwardly projecting rami.

mandible or mandibular bone

Forming the letter O with your lips requires what motion of the TMJ and contraction of what muscle that flattens the cheek?

mandibular depression, buccinator

Clenching your teeth requires what TMJ motion and involves what muscles?

mandibular elevation temporalis, masseter, medial pterygoid

also called the articular fossa, it lies anterior to the external auditory meatus and articulates with the condyle of the mandible

mandibular fossa

name the two bones and their articular surfaces that make up the temporomandibular joint.

mandibular fossa of the temporal bone, condyle of the mandible

what muscle makes up the fullness of the posterior position of the cheek?

masseter

bony prominence posterior and inferior to the ear, to which the digastric muscle attaches

mastoid process

The ? is commonly called the upper jaw. It is located in the middle part of the face and houses the upper teeth. It connects the nasal bone superiorly and with the zygomatic bone laterally and has one main landmark.

maxilla or maxillary bone

what are the prime movers of contralateral lateral deviation?

medial pterygoid, lateral pterygoid

located on the interior side (inside) of the mandible near the midline. It serves as an attachment for the geniohyoid muscle.

mental spine

located just inferior to the condyle

neck

located between the condyle and coronoid process on the ramus

notch

makes up the posterior wall of the fossa and is located just anterior to the external auditory meatus

postglenoid tubercle

the verticle portion of the mandible from the angle to the condyle

ramus

the ? component of the trigeminal nerve involves the facial area, whereas the ? component involves the chewing muscles

sensor, motor

grinding your teeth could involve motions in the sagittal plane and frontal plane. what are these motions?

side to side motion- lateral deviation anterior-posterior motion- protraction/retraction

the ? ligament attaches to the spine of the sphenoid bone and runs to the middle of the ramus on the internal surface of the mandible. It suspends the mandible and limits excessive anterior motion.

sphenomandibular ligament

the ? ligament attaches from the styloid process of the temporal bone to the hyoid bone. its function is to hold the hyoid bone in place

stylohyoid ligament

the ? runs from the styloid process of the temporal bone to the posterior inferior border of the mandible's ramus. It lies between the masseter and medial pterygoid muscles and plays a role in limiting excessive anterior motion

stylomandibular ligament

There are two groups of assistive muscles of TMJ they are?

surprahyoid and infrahyoid muscle groups

the ? is located on the side of the skull posterior to the zygomatic bone, inferior to the parietal bone, posterior to the greater wing of the sphenoid, and anterior to the occipital bone

temporal bone

bony floor formed by the zygomatic, frontal, parietal, sphenoid and temporal bones. It contains the attachment of the temporalis muscle.

temporal fossa

Lies posterior and inferior and joins with the zygomatic process of the temporal bone to form the zygomatic arch.

temporal process

what muscle can be palpated superior and anterior to the ear?

temporalis

What are the prime movers of Mandibular Retrusion?

temporalis (posterior)

What are the prime moves of ipsilateral lateral deviation?

temporalis, masseter

what portion of the temporalis is the most effective line of pull when biting down hard, and why?

the anterior fibers becase they are oriented more vertically

Lateral deviation of the mandible to the left involves both spinning and gliding motions. Describe how that happens.

the left condyle spins in the mandibular socket while the right condyle slides forward

important landmark of the maxilla is

the tuberosity

The TMJ is designed as a ? lever system

third-class lever

What is another term for "adam's apple"?

thyroid cartilage

is the largest of the nine cartilages of the larynx. it is commonly called the "Adam's apple" and tends to be more prominent in males. It lies just inferior to the hyoid bone at about the level of C3 to C4. It provides attachment for the infrahyoid muscles

thyroid cartilage

the sensory component of the facial nerve involves the ?, whereas the motor component involves the ?

tongue area, muscles of the face

the ? nerve is the fifth cranial nerve, which has both sensory and motor components.

trigeminal nerve

The zygomatic arch is made up of which two bones?

zygomatic and temporal bones

formed by two bones: the zygomatic process of the temporal bone posteriorly and the temporal process of the zygomatic bone anteriorly

zygomatic arch

makes up the posterior portion of the zygomatic arch. It serves as the attachment for the masseter

zygomatic process

Mandibular elevation and depression occur in the ? plane.

Sagittal Plane

lies deep to the mandibular fossa of the temporal bone and provides attachment for the sphenomandibular ligament

Spine

Two motions occur during mandibular depression: 1. the disk and condyle glide forward and inferiorly and 2. the mandible rotates anteriorly on the disk. Which occurs first?

anterior rotation of the mandibular condyle on the disk

clicking in the jaw can occur when the ? is not positioned correctly.

articular disk

it is connected circumferentially to the capsule and tendon of the lateral pterygoid

articular disk

makes up the anterior portion of the articulating surface of the temporal bone. when the mandible is depressed, the condyle of the mandible rests under this landmark.

articular tubercle

important landmarks of the temporal bone

articular tubercle mandibular fossa postglenoid tubercle styloid process mastoid process external auditory meatus zygomatic process

the articular portion of the temporal bone consists of the ? articular (mandibular) fossa in the middle, with the ? articular tubercle located anteriorly and the ? postglenoid tubercle located posteriorly

concave, convex, convex

also called the condylar process. it is the posterior projection on the ramus, and it articulates with the temporal bone

condyle

The first movement in depression of the mandible is a ? articulation where the mandibular condyle rotates on the disk creating an anterior glide of the condyle while the distal end moves posteriorly

convex on concave

located anterior to the condyle on the ramus. it serves as an attachment for the masseter muscle

coronoid process

What muscles work like a pulley?

digastric and omohyoid

TMJ muscles that have fibers running more vertically will tend to create ?, whereas muscles that have fibers running more horizontally will be better aligned to produce ? when they contact.

elevation or depression protraction and retraction

the ? nerve is the seventh cranial nerve, which also has sensory and motor components

facial nerve

Which would impair function of the TMJ more: Damage to the mandibular division of CN V or damage to the CN VII?

fifth cranial- trigeminal nerve

Important landmarks of the sphenoid bone

greater wing lateral pterygoid plate spine

is a horseshoe-shaped bone lying just superior to the thyroid cartilage at about the level of C3. It has no bony articulation but is suspeneded from the styloid processes of the temporal bones by the stylohyoid ligaments.

hyoid bone

its main function is to provide attachment for the tongue muscles. However, it also provides attachment for the suprahyoid and infrayoid muscles that assist in mandibular depression

hyoid bone

the ? envelops the TMJ by attaching superiorly to the articular tubercle and borders of the fossa of the temporal bone. Inferiorly, it attaches to the neck of the condyle of the mandible

joint capsule

What are the prime movers of Mandibular Protrusion?

lateral and medial pterygoid

Depression of the mandible (opening of the jaw) involves two motions.

-mvmt within the lower joint space where the mandibular condyle rotates on the disk creating an anterior glide of the condyle while the distal end (ramus/angle) moves posteriorly -motion occurs in the upper joint space and involves gliding the disk forward and downward under the articular tubrecle.

is located at the lateral base of the skull anterior to the temporal bone. It resembles a bat with extended wings. Because of its location, the sphenoid bone connects with six other cranial bones and two facial bones.

.Sphenoid Bone

Sit in a good posture position with your hands on each side of your jaw. Move your jaw from side to side against slight resistance. a. What is the joint motion? b. what type of contraction (isometric, concentric, or eccentric) is occurring? c. Name the muscles responsible for moving the jaw to the right.

1a. mandibular lateral deviation b. concentric c. right temporalis and masseter, left medial and lateral pterygoid

located between the body and the ramus, it is the joining point of the two landmarks. it is often referred to as the angle of the ramus

angle

important landmarks of the mandible are

angle, body, condyle, coronoid process, mental spine

The ? muscle is not considered a muscle of the TMJ because it dos not cross the joint. however it does play an assistive role in chewing by pressing the cheeks agains the teeth.

Buccinator

the Sternohyoid, Sternothyroid, and Omohyoid is innervated by?

C1 to C3 via hypoglossal- CN XII

The Geniohyoid and Thyrohyoid is innervated by ?

C1 via hypoglossal- CN XII

the external opening for the ear, located posterior to the TMJ

External Auditory Meatus

they Stylohyoid is innervated by?

Facial Nerve- CN VII

a large bony process located deep to the zygomatic arch, posterior to the zygomatic bone, and anterior to the temporal bone. As part of the termporal fossa, it provides attachment for the temporalis and lateral pterygoid muscles

Greater Wing

What are the prime movers of Mandibular Depression?

Lateral Pterygoid

Lies deep to and extends inferiorly under the zygomatic arch. It serves as an attachment for the lateral and medial pterygoid muscles

Lateral Pterygoid Plate

Digastric Muscle

O: Anterior-internal inferior mandible Posterior- mastoid process I: Via pulleylike tendon to hyoid A: Assists in depressing mandible N: Mandibular branch of trigeminal nerve (CN-V) and branch of facial nerve (CN-VII)

Mylohyoid Muscle

O: Interior medial mandible I: Hyoid A: Assists in depressing mandible N: Branch of trigeminal nerve (CN-V)

Medial Pterygoid Muscle

O: Lateral pterygoid plate of the sphenoid bone and tuberosity of the maxilla I:d Ramus and angle of the mandible A: Bilaterally: elevation, protrusion N: Mandibular branch of trigeminal nerve (CN-V)

Sternothyroid Muscle

O: Manubrium of sternum and cartilage of the first rib I: Thyroid cartilage A: Stabilize hyoid bone N: C1 to C3 via hypoglossal nerve (CN-XII)

Sternohyoid Muscle

O: Medial end of clavicle, sternoclavicular ligament, and manubrium of sternum. I: Inferior border of hyoid bone A: Stabilize hyoid bone N: C1 to C3 via hypoglossal nerve (CN XII)

Geniohyoid Muscle

O: Mental spine of mandible I: hyoid A: assists in depressing mandible N: C1 via hypoglossal nerve (CN-XII)

Stylohyoid Muscle

O: Styloid process of temporal bone I: Hyoid A: Assists in depressing mandible N: Branch of facial nerve (CN-VII)

Omohyoid muscle OIAN:

O: Superior border of the scapula I: Inferior border of the hyoid bone A: Stabilize hyoid bone N: C1 to C3 via hypoglossal nerve (CN-XII)

Temporalis Muscle

O: Temporal Fossa I: Coronoid process and ramus of mabdible A: Bilaterally: elevation, retrusion (posterior fibers) Unilaterally: ipsilateral lateral deviation N: Mandibular branch of trigeminal nerve (CN-V)

Masseter Muscle

O: Zygomatic arch of temporal bone and zygomatic process of maxilla I: Angle of the ramus and coronoid process of mandible A:Bilaterally: elevation N: Mandibular branch of trigeminal nerve (CN-V)

Lateral Pterygoid Muscle

O: lateral pterygoid plate and greater wing of sphenoid I: mandibular condyle and articular disk A: Bilaterally- depression, protrusion Unilaterally- contralateral lateral deviation N: Mandibular branch of trigeminal nerve (CN-V)

Thyrohyoid Muscle OIAN

O:Thyroid cartilage I: inferior border of hyoid bone A: Stabilize hyoid bone N: C1 to C3 via hypoglossal nerve (CN-XII)

a slender projection positioned down and forward from the temporal bone on the inferior, slightly interior surface. It serves as the attachment for various muscles and ligaments

Styloid process

when an individual has pain or dysfunction in the tmj joint, it is not uncommon to hear ti described by a layperson as "having ?". This of course is inaccurate.

TMJ

The important landmark of the zygomatic bone is ?

Temporal Process Temporal Fossa Zygomatic Arch

What are the prime movers of Mandibular Elevation?

Temporalis, masseter, medial pterygoid

What nerve innervates the Temporalis, Masseter, Lateral pterygoid, and Medial pterygoid and mylohyoid?

Trigeminal Nerve (mandibular branch)- CN V

innervation of the TMJ muscles comes from the cranial nerve ?

Trigeminal Nerve- CN V

the digastric muscle is innervated by?

Trigeminal and facial nerve- CN V, VII

a rounded projection located on the inferior posterior angle. It serves as attachment for the medial pterygoid.

Tuberosity

forms the prominence of the cheek and contributes the lateral wall and floor of the eye orbit. The frontal, maxillary, sphenoid, and temporal bones border it. the ? along with the zygomatic process of the temporal bone from zygomatic arch, to which the masseter attaches.

Zygomatic bone

What are the synonymous terms for the following TMJ motions? a. Opening the Jaw b. Closing the jaw c. moving the jaw posteriorly d. moving the jaw anteriorly e. moving the jaw toward the side

a. depression b. elevation c. retraction/retrusion d. protraction/protrusion e. lateral deviation

Sit in a good posture position with your thumb beneath your chin. Open your mouth against slight pressure. a. what is the joint motion? b. what type of muscle contraction (isometric, concentric, or eccentric) is occurring? c. Name the primary muscle responsible for moving the mouth. d. Name the muscle group that assists with this action. e. The TMJ muscles in what group are acting as stabilizers during this activity? Describe what structure they are stabilizing and what motion they are preventing.

a. mandibular depression b. concentric c. lateral pterygoid d. lateral pterygoid, suprahyoid group e. the infrahyoid group contracts to stabilize the hyoid and prevent it from elevating when teh suprahyoid group contracts

Biting off a tough piece of bread is usually done by placing it in one side of the mouth. a. the biting action requires what motion of the TMJ? b. which side of the jaw experiences some distraction? c. which side of the jaw experiences some compression? d. Identify the force (F) and resistance (R) in this example. e. What class lever system is the TMJ functioning as with respect to this motion? f. What would happen to the force and resistance arms if the bread was moved to the front teeth instead? g. How does this change the amount of force the muscles need to generate in order to bite through the bread?

a. mandibular elevation b. side opposite the bread c. same side as the bread d. F=muscles, R= bread e. third-class lever f. the force arm would stay teh same as the muscle attachments, and joint axis has not moved. the resitance arm would increase as the distance between the joint axis and resistance (pt where teeth contact bread) has gotten longer. g. When biting with the front teeth (long resistance arm), more force must be generated to overcome the larger resistance

Sit in a good posture position with your index and middle fingers on the anterior surface of your lower jaw in the midline. without allowing your fingers to move, push against them with your lower jaw. a. what is the joint motion? b. What typel of muscle contraction (isometric, concentric, or eccentric) is occurring. c. name the muscles responsible for moving the jaw to the forward.

a. mandibular protraction b. isometric c. medial and lateral pterygoid

As you stand in anatomical position, what TMJ muscles are working to resist the force of gravity? How are the contracting?

all muscles of mandibular elevation (temporalis, masseter, and medial pterygoid) are contracting isometrically

the horizontal portion of the mandible; the superior surface of the body holds the lower teeth

body

TMJ problems are frequently associated with ?

cervical dysfunction

? or ? of the teeth is a common nighttime problem that can lead to TMD.

clenching and grinding