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