In summary, the overall function of the TMJ is to allow
movement including; mouth opening, mouth closing, speech and mastication.
Having discussed the structures and components of the Temporomandibular joint,
it evaluates the importance of the TMJ and the impact TMJ dysfunction has on an
individual. Trauma, injury, inflammatory diseases, disorders relating to growth
and poor postures are all subjects of TMJ dysfunction. Although there are
preventive measurements and treatments to help with TMJ, some individuals TMJ
dysfunction may be more severe than others resulting in further treatment such
TMJ dysfunction can also occur if a poorly constructed
dental appliance has been fitted. An example here is where the crown has been
inappropriately made and sits proud above the tooth. This can affect the
individuals bite as the teeth won’t meet in their normal alignment. It’s
extremely important that all appliances are made correctly and when fitted that
they are checked beforehand.
Further treatment such as physiotherapy can be carried
out which include a number of exercises involving relaxing and strengthening
the head, neck and face muscles. Those
suffering from anxiety and have problems associated with the TMJ may be advised
to visit a psychologist to help with stress and provide information and
exercises to overcome stress situations to prevent further strain. The aim of
Physiotherapy is also to help recover stiffness and restore normal function.
Exercises will be given and advise of correct posture. Poor posture can affect
the TMJ. The muscles become over-stretched resulting in tissues of the neck and
jaw becoming strained and sore.
A few recommendations are advised to help with TMJ
dysfunction. Resting and relaxing of the muscles and joints is advised. This
can be carried out by eating soft foods, TMJ exercises and avoid clenching the
muscles (although some individuals are unaware they are clenching especially at
night time). Those that are unaware that they are doing this during the night may
experience a lot of pain the following day. It’s advised that patients attend
their GP or dentist where an appliance such as a bite guard can be provided. A
bite guard can be worn in the day but mostly at night for those patients who do
clench/grind their teeth. Moist heat or ice can be applied to the affected area;
the person is advised to relax while heat or ice is applied. Patients are also
advised to avoid biting nails, chew gum as this can again put unnecessary
pressure on the TMJ.
Trismus is another
symptom that can occur due to involuntary painful contractor of the muscles of
the joint. Enamel wear (attrition) can also impact on the TMJ due to the
grinding of occlusal and incisal surfaces.
There are a number of symptoms what an individual may
experience and may describe these symptoms to either their GP or dentist. These
include; clicking jaw, locked jaw, muscle pain, earache/pain, reoccurring
headaches, neck pain, swelling to the face, sore and tired feeling of the mouth
(including tongue and cheek) when opening and closing, pain when eating, patient
pointing to temple and cheek explaining where the pain is, soreness of jaw
muscles and overall facial pain.
A number of factors can lead to TMJ dysfunction leading
to pain and discomfort for the patient. A common problem is the patient who
tends to grind teeth puts pressure/stress on the TMJ. This is often habitual
(and often done during their sleep) and causes damage to the muscles of the
joint. Patients, who do grind/clench teeth, may be advised to wear a bite guard
if they receiving pain and discomfort of the TMJ. Other causes of TMJ
dysfunction include those who suffer from osteoarthritis or rheumatoid
arthritis in the TMJ. The person may need to have anti-inflammatories or
steroids to relieve their pain. Where this is present in the younger patient,
artificial prosthesis may be considered (artificial prosthesis replacing
damaged joint). If the tissues around the disc or the disc itself have suffered
dislocation, this can also impact on the TMJ. Dislocation may have occurred if
the patient has been in an accident resulting in concussion or facial blow.
Dislocation may impact on the patients bite resulting in TMJ problems as the
teeth are no longer in the normal position.
affect the internal structures and extra-articular disorders (referring to the
outside of the joint) may arise due to the over activity of the jaw
(mastication muscles) or cervical (neck) muscles.
TMJ dysfunction refers to a number of problems that
affect the joint and all its components. It can be intra-articular (referring
to the inside of the joint); caused by inflammation.
The TMJ is supplied with blood via the branches of the
external carotid artery, mainly the superficial temporal branch. There are other
smaller arterial branches that also contribute to the joint’s blood supply
including the deep auricular, ascending pharyngeal and maxillary arteries.
The muscles that are involved with mastication are also
involved in the action of swallowing. However, they are several other muscles
associated with swallowing and perform specific roles in this action. The masseter
and medial pterygoid elevate and close the mandible whilst the temporalis
assist in both of these actions but also retracts the mandible. The lateral
pterygoid enables the mandible to move laterally as well as depression, opening
and protruding of it. These muscles are innervated by the mandibular division
(motor branch) of the Trigeminal nerve (V cranial nerve).
pterygoid’s origin is located in the tuberosity of the maxilla and the medial
surface of the lateral pterygoid plate and palatine bone with its insertion
attached to the medial surface of the ramus and angle of the mandible. The
purpose of the medial pterygoid is to allow the mandible to move sideways and
elevation. The lateral pterygoid is located between the intra temporal fossa
and the condyle of the mandible. This muscle allows protrusion of the mandible
allowing sliding and grinding.
The muscles involved for mastication to take place
include the temporalis, masseter, medial pterygoid and lateral pterygoid, allow
the action of chewing of food. These muscles are located on either side of the face.
The temporalis is located superior to the ear situated on the lateral side of
the head allowing the mouth to open and close. Its’ origin is at the temporal
bone with its insertion point at the coronoid process of the mandible. The masseter
is located in the buccal area (cheek) with its origin in the zygomatic arch and
its point of insertion is on the outer surface of the mandibular ramus and
angle. It’s role is to close the jaw by elevating the mandible.
There are several muscles involved to articulate speech
which involve the following; the mylohyoid (allowing tongue to lift up), the styloglossus
(allows upwards and backwards movement) and the hyoglossus (allows the tongue
to move downwards and backwards). Not only are these muscles responsible for
speech, they are also involved in the ability to swallow and mastication.
Protrusion and retraction refers to movements of the jaw
anteriorly and posteriorly. The superior part of the joint allows protrusion
and retraction of the mandible to take place. The lateral pterygoid muscle and
medial pterygoid allows protrusion (forward movement) to take place. The
Geniohyoid and Digastric muscle allows retraction (drawing back) to take place.
Elevation and depression refers to the opening and closing of the mouth and is
permitted by the inferior part of the joint. Depression (opening of the mouth)
is a passive movement and is mainly caused by gravity compared to elevation
(closing of the mouth) is an active movement which requires the masseter,
temporalis and medial pterygoid muscles to contract.
In order for the TMJ to be stabilised, there are several
ligaments involved. Lateral movement and excessive retraction of the condyle
from the glenoid fossa is assisted by the temporomandibular ligament. It
surrounds the capsule surface running from the zygomatic process to the condyle
borders. The excessive downward and protrusive movement of the mandible is prevented
by the movement of the stylomandibular ligament. This ligament’s origin is the
styloid process and runs to the ramus joining the medial pterygoid muscle. The
Sphenomandibular ligament is a very strong ligament that prevents the excessive
movement of the mandible in the downward and protrusive motion. This ligament’s
origin is the sphenoid bone to the inner surface of the ramus.
Jones, O. (2017). Articulating
surfaces. Retrieved from https://teachmeanatomy.info/head/joints/temporomandibular/
Here is a diagram of the articulation surfaces discussed
The TMJ allows movement of the mandible and plays an
integral part in mastication, swallowing and speech. It is associated with
three types of mandibular movements- gliding, rotational and lateral movement. In
order for these to be performed, the TMJ contains a bi-arthroidal hinge joint
(both surfaces glind against each other) in order for movement to be made. The
structures of the joint include; capsule, articular disc and retrodiscal
tissue. The capsule covers the joint with a fibrous membrane. This attaches the
articular eminence, the articular disk and the mandibular condyle neck
together. The location of the TMJ is anterior to the inner ear and inferior to
the temple. The TMJ allows articulation of the three components; which include;
mandibular fossa, articular tubercle and the head of mandible. Although these
surfaces are all part of articulation, they are not in contact with each other.
The Articular disc separates these components splitting the joint resulting in
two synovial joint cavities. These two cavities are protected by synovial
membrane whereas fibrocartilage protects the articular surfaces.
This assignment will discuss the function and movements
of the Temporomandibular joint (TMJ) and include all its components. An explanation
of what happens during the actions of speech, mastication and swallowing,
including how these movements are limited and controlled. The causes of TMJ
dysfunction and their associated symptoms, causes and treatments will be
identified. The impact a poorly constructed appliance can have on TMJ as well
as the signs and symptoms that a person may present with will also be