Examination of tmj &muscles of mastication (2)


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Examination of TMJ and muscles of mastication

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Examination of tmj &muscles of mastication (2)

  1. 1. •CONTENTS •Introduction •Anatomy of the joint •Ligaments of the joint •Articular disc •Retro discal tissue •Examination of the joint •History taking •Inspection • palpation •Examination of the muscles •Conclusion •References
  2. 2. DEFINITION The temporomandibular joint (TMJ) is the articulation of the mandibular condyle with the glenoid fossa of the temporal bone. Normal movement of the mandible depends on proper function of the TMJ. Externally, the preauricular area lies directly over the joint.
  3. 3. The TMJ is a ginglymoarthrodial joint, a term that is derived from “ginglymus” meaning a hinge joint, allowing motion only backward and forward in one plane, and “arthrodia” meaning a joint of which permits a gliding motion of the surfaces . The right and left TMJ form a bicondylar articulation and ellipsoid variety of the synovial joints similar to knee articulation.
  5. 5. BONY COMPONENTS OF THE JOINT MANDIBLE •It is a “U” shaped bone that supports the lower teeth and makes up the lower facial skelton. •It has no bony attachment to the skull. •The condyle is the part of mandible that articulates with the cranium , around which movements occur. •From the anterior view , it has two projections medial pole : more prominent lateral pole : comparatively less prominent •Mediolateral length : 15-20 mm •Anteroposterior width : 8 -10 mm
  6. 6. TEMPORAL BONE •The condyle articulates at the base of the cranium with the squamous portion of the temporal bone. •This portion of the bone is made up of , a concave mandibular fossa , in which condyle is situated and is called articular or glenoid fossa. •There is a convex bony prominence called the articular eminence. •The degree of convexity of the articular eminence is highly variable and is important because the steepness of the steepness of this surface dictates the pathway of the condyle when the mandible is positioned anteriorly.
  7. 7. THE ARTICULAR DISK (DISCUS ARTICULARIS; INTERARTICULAR FIBROCARTILAGE; ARTICULAR MENISCUS) The articular disk is a thin, oval plate, placed between the condyle of the mandible and the mandibular fossa. Made up of dense collagen,cartilage-like proteoglycans , elastic fibers. Arrangement of collagen fibers: at centre: perpendicular to transverse axis periphery: interlaced and many fibers orient parallel to mediolateral aspect of disc.
  8. 8. Cartilage – like proteoglycans contribute to compressive stiffness of the articular cartilage. Disc is attached by ligaments to medial and lateral poles of the condyle.these ligaments permits rotational movement of the disc on the condyle during mouth opening and closing. Disc is thinnest at the centre and thickens to form anterior and posterior band ,this arrangement stablizes condyle in the glenoid fossa. In between the anterior and posterior band is the intermediate zone which is the thinnest. In the normal joint the articulating surface is located on intermediate zone of the disc.
  9. 9. The disc and its attachment divides the joint into upper and lower compartments that normally donot communicate. Passive volume of upper compartment : 1.2 ml lower compartment : 0.9 ml MEDIAL VIEW OF MANDIBLE: 1.Articular eminence and upper joint space 2.Anterior end of lower joint space 3.Lateral pterygoid muscle 4.Articular disc 5.Posterior end of upper joint space 6.Posterior end of lower joint space
  10. 10. SUPERIOR COMPARTMENT : roof : mandibular fossa floor : superior surface of the disc INFERIOR COMPARTMENT : roof : inferior surface of the disc floor : articulating surface of the mandibular condyle At its margin the disc blends with the fibrous capsule Fibers of posterior one third of temporalis muscle and deep masseter muscle attaches on anterolateral aspect The Synovial Membranes.—The synovial membranes, two in number, are placed one above, and the other below, the articular disk. The upper one, the larger and looser of the two, is continued from the margin of the cartilage covering the mandibular fossa and articular tubercle on to the upper surface of the disk. The lower one passes from the under surface of the disk to the neck of the condyle, being prolonged a little farther downward behind than in front. The articular disk is sometimes perforated in its center, and the two cavities then communicate with each other.
  11. 11. RETRODISCAL TISSUE: A mass of soft tissue occupies the space behind the disc and condyle , also reffered to as posterior attachment. It is loosely organised system of collagen fibres,branching elastic fibres , fat , blood and lymph vessels and nerves. Unlike the disc itself, the retrodiscal tissue is vascular and highly innervated. As a result, the retrodiscal tissue is often a major contributor to the pain o f Temporomandibular Disorder (TMD), particularly when there is inflammation or compression within the joint. POSTERIOR ATTACHMENT
  12. 12. LIGAMENTS OF TMJ: 1.TRUE LIGAMENT:: Fibrous capsule of the joint Temperomandibular ligament 2.ACCESSORY LIGAMENT:: Sphenomandibular ligament Stylomandibular ligament
  13. 13. LIGAMENTS OF THE JOINT A ligament is a structure that connects two bones . As with any joint system , ligaments play an important role in protecting the structures. Ligaments of the joint are made up of collagenous connective tissue that have particular length and they do not stretch . However , if extensive forces are applied to the ligament, whether suddenly or over a prolonged period of time , the ligament can be elongated. When this happens , it compromises the function of the ligament , thereby altering joint function. Ligaments do not enter the joint function actively , rather , they act as passive restraining devices to limit and restrain border movements.
  14. 14. 1.TRUE LIGAMENT:: Collateral ligament Fibrous capsule of the joint Temperomandibular ligament 2.ACCESSORY LIGAMENT:: Sphenomandibular ligament Stylomandibular ligament
  15. 15. COLLATERAL (DISCAL LIGAMENT) •the collateral ligament attach the medial and lateral border of the articular disc to the poles of the condyle. •They are commanly called discal ligament and are two: • medial discal ligament • lateral discal ligament •Medial discal ligament attaches to the medial edge of the disc to the medial pole of the condyle •Lateral discal ligament attaches lateral edge of the disc to lateral pole of the condyle •There function is to restrict movement of the disc away from the condyle. In other words , they allow disc to move passively with the condyle as it glides anteriorly and posteriorly. The attachment of the discal ligament permits the disc to Be rotated anteriorly and posteriorly on the articulating surface of the condyle. Thus the ligament are responsible for the hinging movement of TMJ which occurs between condyle and articular disc
  16. 16. THE TEMPEROMANDIBULAR LIGAMENT (LIGAMENTUMTEMPOROMANDIBULARE , EXTERNAL LATERAL LIGAMENT) The temperomandibular ligament consists of two short, narrow fasciculi, one in front of the other, attached above to: the lateral surface of the zygomatic arch and to the tubercle on its lower border. below : to the lateral surface and posterior border of the neck of the mandible. It is broader above than below, and its fibers are directed obliquely downward and backward.
  17. 17. •The oblique portion of the TM ligament resists excessive dropping of the condyle therefore limiting the extent of mouth opening. •This portion of the ligament also influences the normal opening movement of the mandible •During the normal phse of opening , condyle can rotate around a fix point until the TM ligament becomes tight as its point of insertion on the neck of the condyle is rotated posteriorly. •When the ligament is taut the neck of condyle cannot move further •If the mouth were to open wider , the condyle would need to move downward and forward across the articular eminence.
  18. 18. As the mouth opens,the teeth can be seperated about 20-25 mm , (A to B) without the condyles moving from the fossae As the mouth opens wide (B to C) the condyle moves downward and forward out of the fossae.
  19. 19. •This effect can be demonstrated clinically by closing the patient’s mouth and applying mild posterior force to the chin. •With this force applied the patient shoukd be asked to open the mouth. •The jaw will easily rotate open until the teeth are 20-25mm apart. •At this point , resistance will be felt when the jaw is opened wider. •If the jaw is opened still wider, a distinct change in the opening movement will be felt , which represents change from rotation of the condyle around a fixed point to forward and down the articular eminence. •This change in movement is brought about by tightening of TM ligament.in the erect postural position and with vertically placed vertebral column , continued rotational movement of the mandible would cause impingement of vital sub mandibular and retromandibular structures of neck
  20. 20. •The inner horizontal portion of the TM ligament limits the posterior movement of the condyle and the disc. •When force is a[pplied to the mandible it displases the condyle posteriorly , this portion of the ligament becomes tight and prevents the movement of the condyle into posterior region of the mandibular fossa. •Therefore it prevents retrodiscal tissue from getting traumatized. •The inner horizontal portion also protects lateral pterygoid muscle over-lenghtening or extension •The effectiveness of this ligament is demonstrated during case of extreme trauma to the mandible. •In such cases neck of the condyle will fracture before retrodiscal tissue are injured or before the condyle enters the midcranial fossa.
  21. 21. FIBROUS CAPSULE OF THE JOINT: •It is a thin inelastic fibrous connective tissue envelope that attaches to the margins of the articular surfaces. •It is attached superiorly to whole circumference of mandibular fossa inferiorly to neck of mandible •It stablizes the joint. •It acts to resist any medial , lateral or inferior forces that tend to dislocate the articular surfaces. •The capsular ligament is well innervated and provide proprioceptive feedback regarding position and movement of the joint.
  22. 22. •The capsule is lined by synovium and joint cavity is filled with synovial fluid. •The synovial membrane consists of macrophage type A cells and fibroblast like type B cells , like any other joint. •Synovial fluid is a filtrate of plasma with added mucins and proteins. •Main constituent is hyaluronic acid. •It lubricates the joint and decreses friction during joint compression and motion. •Joint lubrication occurs in two ways: Weeping lubrication Boundary lubrication
  23. 23. WEEPING LUBRICATION : it occurs as fluid is forced laterally during compression and expressed through the unloaded fibrocartilage. As the adjacent areas become loaded , weeping lubrication aids in reducing friction. BOUNDARY LUBRICATION : It is a function of water that is physically bound to the cartiliginious surface by a glycoprotein. DISTINGUISHING FEATURE OF THE JOINT Covered by fibrocartilage rather than a hyaline cartilage. Fibrocartilage is less distensible than hyaline cartilage due to a greater number of collagen fibres. The temporomandibular articulation is unique in the body in that the two joints must always move simultaneously
  24. 24. ACCESSORY LIGAMENTS: The Sphenomandibular Ligament (ligamentum sphenomandibulare; internal lateral ligament The sphenomandibular ligament is attached superiorly to : spine of sphenoid bone inferiorly to : lingula of mandibular foramen It is pierced by : mylohoid nerves and vessels Morphologically , it is remnant of cephalic end of Meckel’s Cartilage (from which mandible develops). It does not have any significant limiting effects on mandibular movement.
  25. 25. STYLOMANDIBULAR LIGAMENT: It is situated on posterior surface of TMJ. Runs from the styloid process to the angle of the mandible. It seperates parotid gland from submandibular salivary gland Morphologically , it is thicken part of investing layer of deep cervical fascia. It is thought to become tense during protrusive movement of the mandible and may contribute to limiting protrusive movement.
  26. 26. THE OTO-MANDIBULAR LIGAMENTS are the discomalleolar ligament (DML), which arises from the malleus and runs to the medial retrodiscal tissue of the TMJ, and the anterior malleolar ligament (AML), which arises from the malleus and connects with the lingula of the mandible via the sphenomandibular ligament The oto-mandibular ligaments may be implicated in tinnitus associated with TMD. A positive correlation has been found between tinnitus and ipsilateral TMJ disorder. It has been proposed that a TMJ disorder may stretch the DML and AML, thereby affecting middle ear structure equilibrium “It thus seems that otic symptoms (tinnitus, otalgia (ear pain), dizziness and hypoacusis) corresponding to altered ossicular spatial relationships can also be produced from masticatory system pathologies.”
  27. 27. BLOOD SUPPLY OF TMJ TMJ is richly supplied by variety of vessels that surrounds it. Predominant is superficial temporal artery branch of maxillary artery Condyle recieves its vascular supply through its marrow spaces by way of inferior alveolar artery and by way of “feeder vessels” that enter directly into the condyle head both anteriorly and posteriorly
  28. 28. NERVE SUPPLY OF TMJ: Sensory innervation of the temporomandibular joint is derived from the auriculotemporal and masseteric branches of V3 or mandibular branch of the trigeminal nerve).
  29. 29. CLINICAL EXAMINATION OF TMJ 1. History taking 2. Measuring maximum interincisal opening 3. Palpation of pretragus area ; the lateral aspect of TMJ 4. Intra – auricular palpation ; the posterior aspect of TMJ 5. palpation of masseter muscle 6. Palpation of lateral pterygoid muscle 7. Palpation of medial pterygoid 8. Palpation of temporalis 9. Palpation of sternocliedomastoid 10.Palpation of digastric
  30. 30. SCREENING HISTORY AND EXAMINATION Because the prevlance of TMD is very high , every patient who comes to dental office should be screened for these problems The purpose of screening history is to identify patients with subclinical signs and symptoms that the patients may not relate but are commonly associated with functional disturbances of masticatory system (headache , ear symptoms) The screening history consists of several questions that will help orient the clinician to any TMD.
  31. 31. QUESTIONS TO BE ASKED: Do you have pain in the face,front of ear and the temple area? Do you get headaches , earaches , neckache , or cheek pain? When is the pain at its worst ? Do you experience pain when using the jaw? Do you experience pain in the teeth? Do you experience joint noises when moving your jaw or chewing? Does your jaw ever lock or get stuck? Does your jaw motion feel restricted? Have you had any jaw injury? Have you had treatment for jaw symptoms?if so , what was the effect? Do you have any other muscle , bone , or joint problem such as arthritis?
  32. 32. FEATURES TO BE INCLUDED IN A THOROUGH OROFACIAL PAIN HISTORY: 1.CHIEF COMPLAINT: A.LOCATION OF PAIN B.ONSET OF PAIN CHIEF COMPLAINT: This should be first taken in patient’s own language and then restated in technical language. If the patient has more than one pain complaints , each complaint should be noted ans when possible , placed in a list according to significance to the patient.
  33. 33. LOCATION OF THE PAIN: •Patient’s ability to locate the pain with accuracy has diagnostic value •The patient’s description of location of pain identifiesonly the site of the pain.it is the examiner’s responsibility to determine whether it is true source of the pain. •If the pain is primary pain , source and site are in same location. •If the pain is heterotropic , the patient will be directing attention to the site of the pain. •One key in locating the source of pain is local provocation that accentuate it. •When pain symptoms become complex , it is sometimes necessary to use selective local anesthetic blockade of tissue to help differentiateb the site from the source •LA blockade of the source of pain will temporarily eliminate the symptoms. •Primary innervation of the joint is by auricular temporal nerve , with secondary innervation from massetric and deep temporal nerves.
  34. 34. Auriculotemporal nerve can be blocked by inserting 27 gauge needle through the skin , just anterior and slightly above the junction of tragus and earlobe. Needle is then advanced until it touches the posterior neck of the condyle. Once the neck of the condyle is felt , tip of the needle is carefully moved slightly behind the posterior aspect of the condyle in anteromedial direction to a depth of 1cm The syringe is then aspired and if no blood is seen , the solution is deposited. If the true source of the pain is the joint , the pain should be eliminated or decreased in approx 5min
  35. 35. ONSET OF THE PAIN: It is important to assess any circumstances that were associated with the initial onset of the pain complaint . These circumstances may give an insight as to cause. For example , in some instances the pain complaint began immediately after a motor vehicle accident. Trauma is frequent cause of pain condition and not only gives insight as to cause but also enlightens the examiner to the other considerations , such as other injury , related emotional trauma. The onset of some pain are associated with systemic illness , jaw function , or may be spontaneous.
  37. 37. INSPECTION Facial asymmetry, swelling , masseter or temporalis muscle hypertrophy muscle Assesment of range of mandibular movements:maximum mouth opening , lateral movement , deviation white opening , protrusive movement
  38. 38. •The maximum opening distance between the incisal edges of upper and lower incisor is measured using scale , Boley gauge or ruler •Normal opening – 40 to 55 mm •Normal opening can also be estimated by patient’s own finger •Normal : three finger end on end •Two finger opening reveals reduction in opening but not necessarily reduction in function •One finger opening indicates reduced function
  39. 39. Maximum mouth opening should be measured without pain as wide as possible , with pain after opening with clinical assistance Mouth opening with assistance is accomplished by applying mild to moderate pressure against the upper and lower incisors with thumb and index finger . passive stretching is a technique for assessing limitation due to muscle or joint problem Assisted opening can be compared with active opening (≥40 mm) This procedure provides the examiner with the quality of resistance at the end of the movement.
  40. 40. •Restricted mouth opening is considered to be any distance less than 40mm. •This distance is measured by observing the incisal edge of the mandibular central incisor travelling away from its position at maximum intercuspation. •If a person has 5mm vertical overlap of anterior teeth and maximum interincisal distance is 57mm , the mandible has actually moved 62mm in opening. •If mouth opening is restricted , it is helpful to test the “end feel” •End feel describes the characteristics of restriction. •End feel can be evaluated by placing the fingers between patient’s upper and lower teeth and applying gentle-but-steady force in an attempt to passively increase the interincisal distance.
  41. 41. muscle restriction are associated with soft end feel and results in increase of >5mm above the active opening (wide opening with pain) joint disorders such as acute non reducing disc displacement have hard end feel and characteristically limit assisted opening to <5mm
  42. 42. LATERAL RANGE OF MOVEMENT Normal lateral range of movement is >7mm Measurements are made with teeth slightly seperated,measuring the displacement of lower midline from maxillary midline. Any condition (tumor, muscle spasm, fracture, ankylosis, displaced meniscus) that prevents the normal translation of one condyle will not prevent the contralateral condyle from sliding forward normally . The result is deviation of the chin toward the affected side .
  43. 43. Examine the hands for signs of systemic disease (e .g., Heberden's nodes of osteoarthrosis, ulnar deviation of rheumatoid arthritis), which may also involve the TMJ . Laboratory tests (e .g., complete blood count, erythrocyte sedimentation rate, rheumatoid factor, antinuclear antibody,serum uric acid) are helpful when a systemic cause for TMJ disease is suspected.
  44. 44. In patients with an intracapsular restriction (disc displacement without restriction) a contralateral eccentric movement will be limited , but an ipsilateral movement will be normal. However with muscle disorders , the elevators (temporalis , masseter , medial pterygoid) are responsible for limited mouth opening , because eccentric movements donot generally lenghten these muscles , nor a normal range of eccentric movement exists.
  45. 45. Observe the opening pattern for deviation . The mandible often deviates towards the affected side during opening because of muscle spasm or mechanical locking by a displaced meniscus
  46. 46. •When the mouth is opened the pathway of mandible is observed for any deviations or deflections. •If deviation occurs during opening and the jaw returns to the midline before 30-35mm of total opening , it is likely to be associated with a disc derrangement disorder. •If the speed of opening alters the location of the deviation , it is likely to be a discal movement (ex disc displacement with reduction) •If the speed of opening does not alter the interincisal distance of deviation , and if the location of deviation is the same for opening and closing , then a structural incompatibility is likely the diagnosis. •Muscle disorders that cause deviation of mandibular opening pathways are commonly large , inconsistent , sweeping movements are not associated with joint sounds. •Deviation can also occur due to subluxation at wide open position.
  47. 47. This is an intracapsular disorder , but not necessarily a pathologic condition. Deflection of the mandibular opening pathway results when one condye doesnot translate.this may be caused by an intra capsular proberm ( disc dislocation without reduction ) With these problems , mandible will deflect to the ipsilateral side during late stages of opening. Deflection can also result if a unilateral elevator muscle , such as masseter becomes shortened (myospasm). This condition can be seprated from intracapsular disorders by observing the protrusive and lateral eccentric movements. If the problem is intracapsular , mandible will move to the side of involved joint during protrusion and be restricted during contralateral movement (ie. Normal movement to the ipsilateral side) If the problem is extracapsular , there will be no deflection during the protrusive movement and no restriction in lateral movements.
  48. 48. When deflection is due to intracapsular source , mandible will always move towards involved joint. If deflection is due to shortened muscle the direction in which mandible moves will depend on the position of the involved muscle with respect to the joint. If the muscle is lateral to the joint , (ie masseter or temporalis) , deflection will be towards the involved muscle. If medial to the joint , (ie medial pterygoid) deflection will be away from the involved muscle (in contralateral direction).
  49. 49. •MALOCCLUSION: •Sometime acute malocclusion occurs. •An acute malocclusion caused by a muscle disorder will vary according to the muscle involved. •If inferior lateral pterygoid is in spasm and shortens , condyle will be brought slightly forward in the fossa on the involved side.this will result in disocclusion of ipsilateral posterior teeth and heavy contact on contralateral canines. •If the spasms are in elevator muscles , the patient is likely to report a feeling that “teeth suddenly don’t fit right” •An acute malocclusion resulting from an antracapsular disorder is usually very closely related to the event that changed the joint function. •If the disc is suddenly displaced , the thicker posterior band may be superimposed between condyle and fossa and cause a sudden increase in discal space.This appears clinically as loss of ipsilateral posterior teeth contact.
  50. 50. If the disc becomes suddenly dislocated , collapse of discal space can occur as the condyle compresses the retrodiscal tissue. The patient notes it as sudden change in occlusion characterized as heavy posterior teeth contact on ipsilateral side. If this condition continues , retrodiscitis may result and cause tissue inflammation with swelling of retrodiscal tissue. The resulting malocclusion may now change to one characterized by loss of posterior tooth contact on the ipsilateral side.
  51. 51. Palpation of pretragus area ; the lateral aspect of TMJ Palpate directly over the joint while the patient opens and the mandible, and the extent of mandibular condylar movement can be assessed . Normally, condylar movement is easily felt . Have the patient close slowly, and you will feel the condyle move posteriorly against your finger.
  52. 52. •opening :involves two motions. First, the mandibular condyle rotates anteriorly on the disk. Second, the condyle and the disk both glide anteriorly and inferiorly over the articular tubercle of the temporal bone
  53. 53. Tenderness elicited by this maneuver is invariably associated with articular inflammation Also , there may be palpable differences in the form of the condyle comparing right and left. A condyle that do not translate may not be palpable during mouth opening and closing. This may be finding associated with an anterior disc displacement without reduction A click that occurs on opening and closing is eleminated by bringing the mandible into a protrusive position before opening is most often associated with anterior disc displacement with reduction. PROVOCATION TEST: it is designed to elicit the described pain. Since pain is often aggravated by jaw use , a positive response adds support for diagnosing TMD. THE STATIC PAIN TEST involves having the mandible slightly open and remainig in one position while the patient resists the slowly
  54. 54. Increasing manual force applied by the examiner in a lateral , upward , and downward direction. If the mandible remains in static position , muscles will be subjected to activation However ability of this test to discriminate between muscle and joint pain is not known
  55. 55. JOINT SOUNDS There are 2 types of joint sound to look out for: Clicks - single explosive noise of short duration. Crepitus - continious 'grating' noise CLICKS •A joint click probably represents the sudden distraction of 2 wet surfaces, symptomatic of some kind of disc displacement. The diagnosis of a joint click, and therefore treatment, varies on whether the click is : left, right or bilateral, painful or painless, consistent or intermittent. •The timing of a click is also significant: a click heard later in the opening cycle may represent a greater degree of disc displacement. •Clicks may frequently be felt as well as heard, though they are not normally painful. •Condylar hypermobility , enlargement of lateral pole of condyle,structural irregularity of eminence. •If the click is relatively loud , it is referred to as a “pop”
  56. 56. CREPITUS : •Crepitus is the continuous noise during movement of the joint, caused by the articulatory surfaces of the joint being worn. This occurs most commonly in patients with degenerative joint disease. •The joint sounds should be listened to with a stethoscope.
  57. 57. Auscultate TMJ noises (not routinely done)
  58. 58. TMJ can also be palpated through anterior wall of external auditory meatus
  59. 59. EXAMINATION OF THE MUSCLES Functional disorders of the masticatory muscles are probably the most common TMD complaint of the patients seeking treatment in the dental office. With regard to pain , they are second to odontalgia in terms of frequency. They are generally grouped in large category known as “masticatory muscle disorder” As with any pathologic state two major symptoms can be observed: 1.Pain 2.dysfunction
  60. 60. PAIN Certainly the most common complaint in patients with masticatory muscle disorder is pain , which may range from slight tenderness to extreme discomfort. Pain felt in muscle tissue is called myalgia. It may arise from increased level of muscle use. Symptoms are usually associated with a feeling of muscle fatigue and tightness. Some authors suggest it is related to vasoconstriction of relevant nutrient arteries and accumulation of metabolic w3aste products in the muscle tissue. Within the ischemic area of the muscle , certain algogenic substances (eg bradykinin , prostaglandins) are released ,causing muscle pain.
  61. 61. Severity of muscle pain is directly related to the extent of the functional activity. Therefore patients always report that pain affects their functional activity. The clinician must also remember that , myogenous pain is a type of deep pain , and if it becomes constant, can produce central excitatory effects. Therefore it can reinitiate more muscle pain (ie cyclic effect) This clinical phenomenon was first described in 1942 as “cyclic muscle spasm” . More recently , with the findings that the painful muscles are not truly in spasm,the term “cyclic muscle pain” was coined. Another very common symptom associated with masticatory muscle pain is headache.
  62. 62. DYSFUNCTION Usually it is seen as decrease in range of mandibular movement. When muscle tissues have been compromised by overuse , any contraction or stretching increases the pain. Therefore to maintain comfort , patient restricts movement within a range that doesnot increase the pain level. Clinically this is seen as inability to open mouth widely.
  63. 63. TEMPORALIS MUSCLE It is a large fan shaped muscle that originates from temporal fossa and lateral surface of skull. Its fibers comes downward zygomatic arch and lateral surface of the skull to form a tendon that inserts into coronoid process and anterior border of ascending ramus.
  64. 64. It can be divided into three distinct areas: Anterior portion : consists of fibers that are direcrted vertically Middle portion : contains fibers that run obliquely across lateral aspect of the skull Posterior portion : that are aligned almost horizontally When temporal muscle contracts , it elevates mandible.
  65. 65. Anterior, Middle and Posterior portions of the temporalis muscle should be palpated
  66. 66. Temporalis muscle can be seen and readily palpated throughout entire length and breadth when the patient’s teeth are firmly clenched.
  67. 67. MASSETER MUSCLE ORIGIN: Superficial portion – anterior 2/3 of lower border of zygomatic arch Deep portion – medial surface of Zygomatic arch INSERTION: Lateral surface of ramus, Coronoid process, and angle of mandible FUNCTION: Elevates mandible, clenches teeth
  68. 68. Palpate multiple areas of the masseter muscle As with temporalis muscle,it can be located when patient’s jaw are forcibly closed.the body of masseter can be palpated with thumb and index finger.index finger can palpate the entire body of masseter.
  69. 69. MEDIAL PTERYGOID / INTERNAL PTERYGOID ORIGIN: Medial surface of lateral pterygoid plate and tuberosity of maxilla and can not be palpated INSERTION: lower medial surface of ramus of mandible FUNCTION: Elevation and protraction
  70. 70. Anterior part of insertion can be palpated by placing the finger at 45 degrees in the floor if the patients mouth near base of the relaxed tongue. The opposite hand can be used to extraorally to palpate posterior and inferior portions of insertion. Body of the muscle can be palpated by rotating the index finger upwards against the muscle to near its origin on the tuberosity.
  71. 71. LATERAL / EXTERNAL PTERYGOID ORIGIN: It originates in two parts: Superior head from the greater wing of sphenoid Inferior head the lateral surface of the pterygoid plate INSERTION: Neck of condyle and articular disc of TMJ. FUNCTION: protraction
  72. 72. PALPATION OF LATERAL PTERYGOID MUSCLE The muscle is palpated by using the little or index finger and placing it lateral to maxillary tuberosity and medial to coronoid process.The finger presses upwards and inwards and a painful response can be determined .
  73. 73. Demonstration of the lateral pterygoid’s attachme anterior articular disc has led to the theory that some anterior disc displacements may be related to its dysfunction. Hyperactivity of the muscle is capable of pullind the disc forward from its normal position.
  74. 74. STERNOCLIEDOMASTOID MUSCLE The sternocleidomastoid passes obliquely across the side of the neck. It is thick and narrow at its central part, but broader and thinner at either end. medial or sternal head , which arises from the upper part of the anterior surface of the manubrium sterni , and is directed superiorly, laterally, and posteriorly. lateral or clavicular head arises from the superior border and anterior surface of the medial third of the clavicle ; it is directed almost vertically upward.
  75. 75. DIGASTRIC ORIGIN anterior belly - digastric fossa (mandible) posterior belly - mastoid process of temporal bone INSERTION: Intermediate tendon (hyoid bone) ACTION: When the digastric muscle contracts, it acts to elevate the hyoid bone. If the hyoid is being held in place), it will tend to depress the mandible (open the mouth).
  76. 76. PALPATION OF THE MUSCLES The SCM is effectively palpated on each side of the neck when the patient moves the head to the contralateral side
  77. 77. REFERENCES
  78. 78. ReferencesB D Chaurasia.Human anatomy:Regional and applied dissection amd clinical,5th edition Drake L R, Vogl W, Mitchell A W M. Gray’s anatomy for student.InternationalEdition. Sinnatamby C S. Last’s anatomy regional and applied. 11th edition. Lippert, L.S. (2011). Clinical Kinesiology and Anatomy, 5th ed. Philadelphia, PA: F.A. Davis. Blaschke DD, Solberg WK, Sanders B . Arthrography of the temporomandibular joint : review of current status . J Am Dent Assoc 1980 ; 100:388 . Kahan LB . Temporomandibular joint dysfunction : an occasional manifestation of serious psychopathology . J Oral Surg 1981 ; 39:742 . Meyer RA. Osteochondroma of coronoid process of mandible . J Oral Surg 1972 ;30 :297 Meyer RA . Clicking sounds owing to temporomandibular joint injury.JAMA 1982 ;248