Musculoskeletal: Temporomandibular

Your examination of the TMJ should include intra-oral palpation of what structures?

*inquire if your patient has a strong gag reflex* Lateral pterygoid: medial aspect of base of molars Medial pterygoid: medial mandibular angle Temporalis tendon: posterior lateral roof of mouth (buccal side)

Describe the arthrokinematic of jaw opening and closing.

1. Rotational movement of the condyles: disc begins to roll posterior while gliding anterior, condyle rolls anterior posterior and glide anterior? (inferior) relative to the disc 2. Translational movement of condyles: condyle and disk glide together, disc is seated on head of the mandible and both move anterior to complete opening.

Mandibular depression occurs at the A. _________________ TMJ. Motion then begins at the B. ________________ TMJ.

A. Lower: Condyles pivot on the intra articular disc (~11 mm of depression) B. Upper: causes anterior translation of the disc on the articular eminence, normal total mandibular depression is 40-50 mm

What is the purpose of the articular disk of the TMJ?

Biconcave, sepparates the joint into two distinct functional components. The disk is made of fibrocartilage. Why important?

How is joint loading of the TMJ performed?

Bite a stack of tongue depressors forcefull on one side to assess contralateral loading. Do this cautiously with patients with OA (very irritating)

What components of movement quality should be assessed with mandibular AROM?

C deviation (image): hypomobility occurs towards the side of deviation and is usually indivative of a capsular pattern S deviation: muscular imbalance or (when present with joint noise and opening restriction) disc involvement. *if present in opening, should see reversal with closing*

What is the close packed position, rest position and capsular pattern of the TMJ?

CPP: maximal closing of the jaw with teeth clenched, maximal retrusion RP: no contact between maxillary and mandibular teeth, tongue against palate just posterior to upper central incisors Capsular pattern: ipsilateral deviation, limited opening

How are structures in the mouth named in relationship to the teeth

Cheak side is buccal, tongue side is lingueal

How is TMJ recursion measured?

Compression of retrodiscal tissue (highly innervated).

What is the functional of the lateral pterygoid?

Contralateral deviation, jaw protrusion, opening, checking post. Disc. Translation in early opening and ant. Rotation of disc during closing.

Order the following in terms of the arthrokinematic of mouth opening: A. Transitional movement of condyles B. Disc begins to roll posteriorly while the condyle rolls anterior (inferior) relative to the disc (i.e. disk moves first?) C. Disc is seated on the head of the mandible and both move anteriorly D. Rotational movement of the condyles

D and B at the same time, A and C at the same time.

What are the muscles of mastication that depress the mandible?

Digastric (ant/post belly) - depress mandible stabilize the hyoid bone Stylohyoid - elevate and retract the hyoid bone - swallowing difficulties when these are impaired

Examination of the TMJ should include observation of what features?

Facial symmetry, forward head, hypertrophied facial muscles jaw position (lateral deviation), teeth symmetry, tooth wear (bruxism), bite allignment (image) and resting position:

What special questions should you ask during your assessment of the TMJ joint?

Has your dentist ever told you that some of your teeth are worn? Do you know if you grind your teeth at night? Does your bite feel off (especially post head/neck trauma), has your jaw ever locked, do you intentionally avoid eating certain foods because they cause jay pain?

What CT structures support the TMJ?

Joint capsule Temporomandibular: lateral support to the TMJ Sphenomandibular: fulcrum and stabilizes TMJ, mylohyoid artery and nerve Stylomandibular: provides weak auxillary support to the joint

What may cause an opening limitation in the TMJ?

Joint hypomobility (can come from any other joint), muscle tightness, trigger points, internal derangement (not maintainig congruancing with mandibular condyle), OA

How is TMJ lateral deviation assessed?

Mouth should be slightly open, deviated left and right, measured using a therabite between two points of reference. 10-15 mm is normal, should be symmetrcal. Should do active, passive and OP (gentle): ipsilateral pain potentially ligamentous or joint capsule - contralateral pain? Image: left sided OP

What MMT should you perform for the TMJ?

Opening, closing, deviation, and tongue strength (tongue trength via hypoglossal nerve, CN XII)

How should TMJ AROM be assessed?

Opening: mandibular depression, intra incisional distance normally 40-50mm, measured as distance between tips of front incisors. only 25-35 mm necessary for normal function. Can use finger width test (2-3 of patients finger widths of non-dominent hand is normal)

What is tongue thrusting?

Pressing tongue against the back of the teeth

What history findings suggest TMJ involvement?

Primary complaints: orofascial pain, HA, ear ache, neck pain, dizziness, difficulty swollowing, referral from trigeminocervical complex (trigeminal, facial, glossopharyngial, vagus and C1-C2 spinal nerves) Limited mouth opening, locking (physically unable to open/close, internal derangement of the disc) pain, deviation during opening. Joint noise (crepitus or clicking, common)

What might clicking and pain in the TMJ with closing indicate?

Retrodiscal tissue being compressed with closing motion, clicking as it reduces out od the way.

How should TMJ joint noises be assessed?

Sound of the articular disc reducing. Use stethoscope. Normal: On opening, reciprocal (clicking with both opening and again with closing in same range of motion, approaching occlusion). Abnormal: - late clicking upon opening after roll and slide have already begun. Condyle is going through motion without the protection of the disk. - clicking at maximal opening: hypermobility with deviation to controlateral side, this individual will probably have hypermobility elsewhere.

Passive motion of the TMJ should include what?

TMJ distraction

What are the muscles of mastication that elevate the mandible?

Temporalis: elevates the mandible Masseter: elevates the mandible and creates ipsilateral deviation Medial Pterygoid: elevates the mandible, contralateral deviation, jaw protrusion

What are the precipitating factors to TMJ dysfunction?

Trauma, struck on the jaw, nail biting, gum chewing, surgery requiring intubation, dental work, cumulative effect of microtraumas. Intrinsice trauma such as teeth clenching, stress/anxiety, bruxism. Contributing factors from cervical and subcranial spine pathology

What are the three commonly seen bite abnormalities?

Underbite (always considered abnormal): results in condyle being in protrusion position w/increased shear or Over bite (2-3 mm is normal): results in recursion position, closed packed position, increased compressive forces, measured with tongue depressor [Both referred to as malocclusion]

What are the two joints of the TMJ?

Upper joint - plane gliding joint Lower joint - hinge joint (mandibular depression occurs here) Both covered in articular cartilage with the CPP being full occlusion (mouth all the way closed?)

How is TMJ protrusion measured?

Usually use therabite. Needed to initiate opening. Protrusion is gliding without roll. Results in shearing of disk. Retrodiscal tissue under stretch. 3-6 mm normal

Your examination of the TMJ should include extra-oral palpation of what structures?

Zygomatic arch, temporalis, TMJ, Mandible: masseter, parotid gland, submandibular gland SCM, upper trap, suboccipital muscles