Diagnostic aids part 3, {photograph and radiograph, BMR, EMG}

1. 1 Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs} } {BMR and EMG {BMR and EMG} } Prepared by Prepared by Dr. Mohammed Alruby Dr. Mohammed Alruby Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Radiographs Means: A procedure that uses a type of high-energy radiation called x-rays to take pictures of areas inside the body. X-rays pass through the body onto film or a computer, where the pictures are made Types: Intra-oral radiographs: Periapical radiographs: It is necessary for any orthodontic diagnosis for the following reasons: The pattern and amount of root resorption of deciduous teeth Presence or absence of permanent teeth, their size, shape, position and relative state of development Congenital absence of teeth or presence of supernumerary teeth Character of alveolar bone, lamina dura, and periodontal membrane Morphology and inclination of permanent teeth roots Pathological oral condition such as thickened periodontal membrane, periapical infection, root fractures, cysts, retained deciduous teeth Abnormal path of eruption of permanent teeth Malposition of individual as: rotation, which requires a larger space on the arch Very useful in mixed dentition analysis Recognition of exact position of impacted tooth by using method of parallax: that determine whether the unerupted tooth is located labially or palatally. Two periapical radiograph is taken with the film in the same position in each exposure, but the tube is moved in second exposure about 10cm. if the impacted tooth is moved in the same direction as the tube so the tooth is impacted palatally and the reverse is versa. Bit-wing radiographs: Is used mainly for detection of proximal cries, but it is of little value in orthodontic diagnosis Occlusal film: Occlusal projection is useful to locate the supernumerary teeth at the midline (mesiodens) and to determine accurately the position of impacted maxillary cuspids Extra-oral radiographs: Cephalometric radiographs: Lateral cephalometric radiographs PA cephalometric radiographs Lateral oblique cephalogram: The patient is directed by 45 degree and take the shot Since dentofacial structure will be superimposed in the true lateral cephalometric projection, the lateral oblique direction is designed to gives a more accurate recording of the actual tooth position in either the left or right buccal segments depending on which side is approximately perpendicular to the central rays The lateral oblique cephalogram combines most of advantages of the lateral views, intra-oral periapical survey and panoramic radiograph plus a standard cephalometric registration that makes possible measurements of bone size and eruptive movements so it is of particular size in analysis of developing dentition Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

3. 3 Submental vertex cephalometric: Is used to assess mandibular asymmetry in the transverse and anterior-posterior plane. It is an important aid in detecting asymmetry in the symphysis, body, ramus, and condyle of the mandible. In many cases of asymmetry, this view is important for evaluation of mandibular displacement or rotation of the entire mandible Panoramic radiograph: Types: Panorex: Developed by Hudson et al 1957, the film and x-ray tube rotate around the mobile head, switching in the mid-course between the left and right sides. The result in double exposures of the structure located at the midline, so that, the film is cut at the midline and the central blurred area is removed and the two halves are taped together Rotograph: Developed by Paatero and modified by Blackman 1960 The patient and the apparatus are rotated in opposite directions The resulting film is a continuous image from condyle to condyle Orthopantomograph: Developed by Paatero 1961, 3 axis of rotations are used, the x-ray tube and the cassette rotates around the head. The film is mobile while the patient is mobile Panograh: Developed by Walter and modified by Blackman 1960—1961, This method is not based on laminograph as most panorama but brings the x-ray source into the mouth. A flexible cassette is surround the mandible and other surround the maxilla, so that, two separate panoramic view are obtained for both maxilla and mandible because of the short x-ray tube – film distance, the magnification is about double to the natural size of the teeth Sectograph: Developed by Ricketts 1962, the patient is seated according to the cephalometric requirements, the x-ray tube and the film travels in recti linear motion instead of curve This result in panoramic unilateral view of each side of the face, in addition, frontal view can be obtained at any desired level Importance of panoramic radiograph: Panoramic view records the teeth and their supporting structures from condyle to condyle without superimposition, so it important to: Visualize in one film, the relationship of both dentition, both jaws and both TMJ Study the relative developmental status of the teeth, it is important in mixed dentition analysis, it gives an idea about: Sequence of calcification: compared to the normal standard as Nolla stages of calcification Prediction of eruption from sequence of calcification To know the sequence of eruption of the teeth To study the pattern of primary teeth root resorption To detect abnormal path of eruption To ascertain any pathological lesion To detect any abnormalities in the teeth number (congenital absence and supernumerary teeth), tooth size and morphology Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

4. 4 The panoramic radiograph shows a differential enlargement so it cannot use cephalometric measurements Hand wrist radiograph: Radiographs of TMJ: Clinical Photographs Facial photographs are of great importance when the extra oral radiographs are not available, are of great importance as pre-treatment and post-treatment permanent records by which the facial changes achieved by treatment and / or growth can be easily detected Importance of facial photographs: To determine facial type of the patient: dolichocephalic, brachycephalic, Mesocephalic To determine the facial profile: convex, concave, straight profile To study the soft tissue relationship especially the lips during the rest and during smiling To study the facial harmony and balance and to detect any facial a symmetry Used as pre-treatment and post-treatment records for detection of changes due to growth and / or treatment and for discussion the case with the parents Teaching needs: slides are probably the most important teaching aids in orthodontics if cases are to be used in lecturer, posts, and papers and presentation In all position, the head of the patient should be oriented according to the cephalometric orientation so that: = the FH plane should be parallel to the floor = it is best to take the photographs when the patient in the cephalostate. The camera is attached to the x-ray cone = to avoid distortion, it is usually necessary to utilize a telephoto lens, two 100 watt light source should be placed on each side of the face, or by using an electronic ring flash 1st position: = the patient is sitting in an upright position with the teeth in centric occlusion and lips in repose position = take frontal and profile views 2nd position: = The patient is sitting in an upright posture with the mandible in physiologic rest position = Take frontal and profile views 3rd position: = The patient is sitting in an upright posture while smiling = Take frontal and profile views = This position is helpful in detection of short upper lip and gummy smile Physioprint photographs: Sassoni photographs: = reproduce the contour of the face at different levels of depth = it provides a contour map of the face, as well as an accurate facial dimensions = when the contour and dimension of the face are considered, no two faces are similar = physioprint can be used to produce synthetically the 3 dimensional architecture of the face The set up: A slide representing a millimeter grid is projected onto the face using a standard slide projector (2x2 or 3x4 inches) which placed 100 inches away from the patient Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

5. 5 The millimeter grid has two heavy lines one vertical representing the midline of the face and the other is horizontal and represent the FH of the patient so, the grid should be adjusted on the face, so that, the vertical line is coinciding with the patient face midline and pass through nasion, and the horizontal line should coincide with FH and pass through the orbital and tragus of the ear The subject is seated in upright position (in cephalostate) facing to the projector and photograph is taken at a right angle to the side of the face The camera and film: The accuracy of this method depends on the following condition: The camera and projector should be oriented at right angle to each other The camera, projector and FH should be at the same horizontal level Distortion and magnification can be completely avoided if the camera is 60 inches from the subjects and the projector is 100 inches from the subjects This method has two major applications: Serial growth study of the facial soft tissue structure by taken a serial physioprint of the same patient at a regular interval (physioprint is a standardized photo) Comparison of changes occurred by growth and /or treatment with original pre-treatment physioprint Furthermore, it can be used for anthropometric studies of racial variation in the face 3 dimensional form of physioprint can be used in study of facial balance in 3 dimension of the face Standardized orthodontic views: For complete photographic record, the recommended views are: Initial: Four extra-oral: left profile (right profile in only cases with facial asymmetry), Three quarter profile, full face, Five intra-oral: occlusion right and left buccal segment, anterior view, upper and lower occlusal surface Close up of any areas of concern, fractured cracked, or non-vital teeth or area of hypoplasia Progress: during the treatment or between phases of treatment: same as the initial stage of treatment close up: of any of unusual or noteworthy mechanics or problem area, removable appliances used during treatment are often photographed in case to be presented. End of treatment: Same as initial: photographs of the retainer can be useful, and also for functional occlusion Right and left lateral excursion and anterior protrusion will be demonstrated Clinical procedure: Photographs should definitely proceed impressions, since alginate invariably remains on lips and cheeks and between the teeth. take extra-oral before intra-oral photographs because the patient lips will be pulled and stretched during the intra-oral photograph Extra-oral photographs Full-face extra-oral view: = A symmetrical shot from the top of the patient’s head to an inch or two below the chin = Take one full face view with the lips at rest and one with as broad smile as possible, fully exposing the teeth and gingivae Frontal at rest: Mandible in rest position ad lips should be in repose position. Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

6. 6 Frontal with teeth in intercuspation: Lips is closed even with strain position for the patient, this photo serves as clear documentation of lip strain and its esthetic effect The lip together picture is recommended in patient who have lip incompetence Frontal with smile: The smile picture demonstrate the amount of incisors show on smile and an excessive gingival display Close up image with posed smile: This view is now recommended as a standard photograph for careful analysis of smile relationships Profile extra-oral view: A photograph from the top of patient’s head to an inch or two below the chin The patient’s nose should be a short distance from the edges of the frame, the back of the head is not essential Profile at rest: The lips should be relaxed. Lip strain is illustrated better in frontal Profile with smile: Allows one to see the angulation of the maxillary incisors Three quarter extra-oral view: A shot from the top of the head to one or two inches below the chin The patient’s body should be at a right angle to the camera as in the profile Focus on the cheekbone and the side of the nose to ensure adequate depth of filed The patient in natural head position looking 45 degree to the camera Oblique at rest: useful for examination of the midface and is particularly informative of midface deformities including nasal deformity. For patient with facial asymmetry, oblique views for both sides are recommended Oblique on smile: reveals characteristic of smile that cannot obtained from the frontal view and certainly not obtained from cephalometric analysis Oblique close up smile: allows more precise evaluation of the lip relationships to the teeth and jaws than is possible using the full oblique view Optional submental view: This view may be taken to document mandibular asymmetry, in patients with asymmetries the submental views can be particularly revealing Silhouette photograph: In photography, a silhouette is defined as an outline that appears dark against a light background. More specifically, it is where your subject is seen as a black shape without detail against a brighter background. This is an artistic outcome that many photographers like to perfect. This effect can be achieved with any kind of bright light source, but of course the most commonly used is the sun around sunrise or sunset. The backlighting from the sun shadows everything towards you and produces this effect. Intra-oral photographs: 5 different views are necessary, 3 of which (frontal, right and left view) should be taken with teeth in occlusion. Other 2 views for maxillary and mandibular arch Check retractor is used to allows proper exposure of teeth, gingiva and alveolar mucosa Importance of intra-oral photographs: 1-The most valuable intra-oral photographs are buccal and frontal views with the teeth in occlusion since they enable the dentist to check the occlusion and to classify the malocclusion more accurately Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

7. 7 2-Useful in discussion with parents 3-Used as permanent records to which the changes due to treatment and / or growth can be compared 4-It is very useful in detection of some condition which cannot be seen on the dental cast as, gingival condition, enamel hypoplasia, and discoloration, mottled enamel, amylogenesis imperfecta, Intra-oral anterior view: Objectives: to show the teeth in intercuspation with viewfinder completely filled with teeth, the buccal surface of molar may be visible Subject: the patient seated on dental chair and the assistant retracting the lips and cheeks, ask the patient to keep the tongue back to allows good contrast for the teeth Procedure: because anterior shots require maximum retraction, larger retractors must be used on all patients Ask the patient to swallow before placing the retractors and aspirate excess saliva from the field of view. For adequate depth of field, focus on the lateral incisors area or the mesial of the canine by rocking gently backward and forward Intra-oral buccal view: Objectives: to show the teeth in maximum intercuspation from the labial surface of the central incisors to the distal of the first molar or the second molar the occlusal plane parallel to the upper and lower edges of the frame the frame should be filled with dental tissue not with lips, skin, fingers, or retractors Subject: the patient seated upright in dental chair with the head turned as far as possible to the left or right to make the job of the photographer more easier Ask the patient to keep the tongue away from the teeth to help clear the photographing field from saliva, keep an aspirator ready to clear excess saliva if necessary Procedure: use a large retractor to pull the cheeks as far as distally away from the teeth to make sure that distal surface of the molars can be recorded Try to move perpendicular to a tangent to molar premolar area so that the sagittal discrepancy will be fully represented on film Upper occlusal view: Objectives: the entire view finder should be filled with teeth showing the maxillary arch from 1-2 mm anterior to the labial surface of the central incisors to the distal of at least the 1st molars, if the 2nd molars erupted try to include them. The middle of the arch should be parallel to the dimension of the frame Subject: the patient should be seated upright on dental chair with the head and body tilted back slightly. The mouth is wide open and the chin is tilted slightly toward the floor The tongue should be held below the mirror to keep it out of view The palatal surface of most of incisors should be visible Procedure: the mirror shots are the hardest to take, at least one pair of hands and preferably two are needed to help. Use retractor to pull the upper lip upward, laterally and forward. Ensure that the lips are away from the labial surface of incisors Keep the fingers and the retractors out of the shot and avoid a direct view to the tips of opposing teeth Warm the occlusal mirror in water for a few seconds then dry it by paper towel, before inserting the mirror ask the patient to swallow to keep saliva away from the field of view Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

8. 8 Place the mirror in the mouth with the large end against the distal margin of the terminal molars, press the mirror down onto the lower incisors and at this point the patient will tend to close so usually reminded to open as much as possible Ask the patient to breathe through the nose for a moment to reduce the fogging, the assistant should ready to gently blow the air syringe on the mirror if it start to fog particularly at the maxillary molar area Angle the camera at 45 degree to the mirror which in turn is angled at 45 degree to the arch then ask the patient to more open to allow taking the shot Lower occlusal view: Objectives: fill the view from anterior to labial surface of lower incisors to the distal of the 2nd molars, the midline should be entered in the view Subject: the patient seated with the body slightly tilted backward and the head tilted as far back as possible. Ask the patient to place the tongue above and behind the mirror is possible Procedure: this shot require an assistant. The lips are pulled downward, laterally and slightly forward by retractor to show the mucosa as a background to the incisors Try to avoid getting, fingers, retractors, or opposing incisors tip in the field of view Use the same magnification in both upper and lower occlusal shots to allow comparison, have a patient to open wide as possible and at the last moment move the distal end of the mirror slightly away from the terminal molars Common error in clinical photography: Extra-oral shots: 1-Misrepresentation of skeletal pattern: this can occur if the patient tilts the head too far backward or forward. Try to get every patient into FH plane or natural head position 2-Inconsistent magnification between stages of treatment, marks on the barrel of lens indicate the proper positions for both intra-oral and extra-oral shots, the lens can be blocked at the required magnification with a screw turned to finger tightness Intra-oral shots: 1-Lack of symmetry: the occlusal plane should be horizontal and bisecting the frame, and the clinically corrected midline should be right at the center of the slide. The viewfinder should be filled with the teeth 2-Some of teeth out of focus: in intra-oral anterior shots, the focus should be in the lateral incisors In intra-oral buccal shots, the focus should be on the premolars, depth of field is not an issue in mirror shots, since all the teeth are on the same plane 3-Backdrop of oral mucosa not provided: if the correct retractors are selected and the lips are pulled not only laterally but forward, the oral mucosa rather than skin will be form a background for all teeth in all views 4-Foreshortening: if the patient does not open wide enough for mirror shots, foreshortening and arch distortion will occur. The occlusal mirror should be rested against the most distal tooth in the arch being photographed, then placed on the opposing incisor tips When ready to take a photograph, ask the patient to open twice as wide because the variation in the size of dental arches Always photograph the larger of the two arches first, filling the frame with teeth and keep the same magnification for the smaller arch 5-Misrepresentation of sagittal discrepancy: when first taking orthodontic photographs, many clinicians believe that sufficient retraction for buccal views will inflict undue pain on Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

9. 9 patients. The photographer must hold the retractor on the side being photographed, since only he or she can pull that extra 5mm distally immediately before the shutter is occur Photographic analysis: For the analysis of the relationship between the craniofacial skeleton and the soft tissue facial contours, profile and frontal photographs are taken under standard conditions Depending on the location of subnasal point relative to the skin nasion perpendicular there are typical profile variation: Average face: subnasal lying on the skin nasion perpendicular Anteface: subnasal lying in front of the skin nasion perpendicular Retroface: subnasal lying behind the skin nasion perpendicular The clinical value of the photographic picture is that it is more realistic and gives a better record of any changes in the soft tissue profile during the course of treatment which is a great advantage Another analysis based on the divergence of the face, the inclination between the two reference lines is her analyzed a-The line joining the forehead and the border of upper lip b-The line joining the border of the upper lip and the soft tissue pogonion The following profiles types are differentiated according to the relationship between these two lines Straight profile: the two lines form nearly a straight line Convex profile: the two reference lines form an angle indicating a relative backward displacement of the chin (posterior divergent) Concave profile: the two reference lines form an angle indicating a relative forward displacement of the chin (anterior divergent) Frontal view: analysis of the frontal picture is important in assessing major disproportion and asymmetries of the face in the transverse and vertical planes For clinical analysis, it has proven practical to mark the two orbital points and to construct the skin nasion perpendicular. Basal metabolic rate (BMR) Definition: minimum amount of energy required by the body to maintain life at complete physical and mental rest in post absorptive state Definition: amount of energy produced in unit time (one hour) under basal condition which are: 1-Complete physical and mental rest: Patient must be comfortably in bed for ½ hour before the experiment, he should not sleep (this lowers metabolism). Emotional stress should be avoided because: - It produces sympathetic over-activity - Increase metabolism Basal arterial blood pressure and heart rate should be obtained, mental rest is important as physical rest 2-Post-operative state: This occurs 12-14 hours after the last meal, the digestive system is at rest. Last meal is at 7 pm and measurements of BMR at 9 am next morning. This prevents the stimulating effect of food on metabolic rate (MR) 3-Comfortable external temperature: Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

10. 10 The person should not feel cold or heat neither shivering nor sweeting, comfortable temperature is 20 -25 degree for dressed persons and 28 -31 degree when naked Basal metabolic rate expressed: As the amount of heat (in calories) given by the body per square surface area /hour under basal conditions This BMR standard which differs with age and sex Clinically BMR is expressed as % deviation from the normal standard. Normally BMR is -+15% of standard value for the age and sex of the person Basal metabolic rate represents: Activity of heart, respiration, muscle, liver and skeletal muscle tone. It is the unavoidable cost of life. It is not the minimal energy expenditure possible because it is reduced by many factors as sleep Measurements of BMR: 1-Direct calorimetry: In which the heat produced by the person during a specified time is actually measured by use apparatus called (body calorimeter) It is an air tight and heat insulated room containing a bed for a person, the heat produced by the person is absorbed by cold H2O running in metal tubes inside the apparatus BMR = total amount of heat produced from the body in one hour / body surface area 2-Indirect calorimetry: BMR: = O2 consumption / hour (liters) X 4.8 / body surface area Normal value of BMR: 1600 cal /day in man and 1400 cal/day in women N: B: BMR is more related to body surface area because it is through the body surface that heat is lost to the atmosphere Factors affecting BMR: -Physiological factors -Pathological factors -Chemical factors A-Physiological factors: 1-Age: Newly born infants: 25 c / H / m 2 –5 years : 60 c / H / m Puberty: 55 c / H / m 20 years: 40 c / H / m After 20 years: 1.0 cal decrease for every 10 years 2-Sex: BMR is lower in females than males by 7%, this differences are not due to endocrine differences because it is present in children, it may be due to greater stores of fat in females. Fat has little metabolic activity 3-Physical habits: Athletes have higher 10% BMR than ordinary persons, this due to their muscle bulk and small store of fat Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

11. 11 4-Dietetic habits: The habits of eating protein- rich diet for a long period increases BMR by 10% more than eating carbohydrate 5-Climate: BMR higher 10% in cold and temperature zones as Eskimo than in hot zones living in hot countries decreases BMR 10% 6-Race: Pure races as Chinese and Indian have lower BMR than mixed races as American and Egyptian. Also dark races have lower BMR than white races 7-Sleep: BMR is decreased by 10% during sleep due to decrease in muscle tone and sympathetic activity 8-Pregnancy: BMR gradually increases during pregnancy till it is doubled by its end. This is due to increase in activity of thyroid gland and the added metabolism of fetus after delivery BMR become normal 9-Starvation: during starvation; decrease in BMR up to 50% has been reported B-Pathological factors: Factors that increase BMR: 1-Hyperthyroidism: Thyroxine is the most powerful stimulants for cell metabolism, so excess thyroxine secretion is accompanied by a marked rise in the BMR up to 100% or even more 2-Hyperpitutarism: Increase BMR by increasing the production of growth hormone which stimulate body metabolism and of thyroid stimulation hormone which stimulate thyroxine production by thyroid gland 3-Hyperadrenalism: Tumors of supra-adrenal medulla are associated with attacks of marked increase in BMR due to excessive formation of adrenaline by the tumor 4-Fever: A raise of body temperature by 1 degree elevates BMR by 13% 5-Blood disease: Over-activity of bone marrow or lymphatic tissues as in polycythemia, leukemia or anemia cause marked increase in BMR 6-Heart failure: The increase in BMR may be due to the increase in activity of respiratory muscles due to dyspnea as difficulty in respiration, usually present 7-Diabetes insipidus: (Marked increase in urine volume), the increase in BMR is to maintain body temperature constant by raising the temperature of the large amounts of water taken orally since they are usually at temperature lower than temperature of the lost volume of urine Factors that decrease BMR: 1-Hypothyroidism: due to decrease in secretion of thyroxine 2-Hypopituitarism: due to atrophy of endocrine glans controlled by anterior pituitary gland 3-Hypo-function of adrenal cortex: due to decrease in secretion of corticoids which normally stimulate metabolism Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

12. 12 4-Under-nutrition: lowered BMR is due to decreased production of endocrine secretions (thyroxine, adrenaline and corticoids) 5-Hypothermia: drop of body temperature by 1 degree cause decrease in BMR by 13% C-Chemical factors: 1-Thyroxine: is the most powerful physiological metabolic stimulants, 1m gm of it produce 100 degree 2-Adrenaline: increase BMR rapidly and for short period 3-Adenosine triphosphate: ATP: decrease BMR in severe hyperthyroidism Electromyography EMG Motor unit potential Electromyography: A technique of recording of total electrical activity of motor nerve and the muscle under study. Electromyograph: Machine used to record graph Electromyogram: record obtained Benefits of EMG: 1-Allows to directly look into the muscle 2-Allows measurements of muscular performance 3-Helps in decision making both before and after surgery 4-Helps patient to find and train their muscles 5-Allows analysis to improve sports activities During normal twitch of muscles fiber, a minute electrical potential is generated which dissipated into surrounding tissue and hence can be detected on the skin above the muscle, the duration of the action potential associated with this twitch is about 1-4 ms Since all muscle Fibers of a motor unit do not contract at exactly the same time. Some being delayed for several milliseconds, the electrical potential developed by single twitch of all the fibers in the motor unit is prolonged. The electrical result of the motor unit twitch, there is an electrical discharge on motor unit potential lasting about 5 -8 ms (and often as long as 12ms) the majority of these motor unit potentials have an amplitude of around 0,5 mv Motor unit potential may be detected by an electromyography which is a high g is a high gain amplifier to which electrodes are connected. The electrodes The electrodes are placed either on the skin above the muscle (skin electrode) or into the muscle needle. When motor unit potentials obtained by electromyography are displayed on cathode ray oscilloscope *** Factors affect the final size and pattern of individual motor unit potential that record: 1-Distance of unit frame 2-Electrodes 3-Types of electrodes 4-Equipment used Clinical application of EMG: 1-Kinesiology: to assess degree and sequence of contraction of muscles in movements 2-Grading the force of muscular contraction Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby

13. 13 3-At rest when normally there is no spontaneous muscle activity 4-Clinical diagnosis and follow up of neurogenic and myopathy disease -Neurogenic disease: problem in nerve fibers -Myopathy disease: problems in muscle fibers EMG in different disease: Neurogenic disease During rest Spontaneous activity (due to loss of inhibitor) Increase force of contraction surviving ones are bigger ( bigger amplitude) Maximum contraction Myopathies No activity Decrease number of motor unit but Decrease size of motor units (amplitude and duration) Decrease interference pattern Decrease amplitude duration and interference According to Henneman principles (Henneman et al 1974) under normal condition, the smaller potential appear first with slight contraction, as the force is increased larger and larger potential are recruited, this being the normal pattern of recruitment. This normal pattern is absent in case of partial paralysis due to injuries or lesions of lower motor neurons as: the small potential nerve appears because only the larger motor unit have survived Two common abnormalities that may be detected at rest when normal muscle is quiescent are fibrillation and fasciculation: 1-Fibrillation: -Contraction of single muscle cells which have become completely dissociated from nervous control due to destruction of motor nerve and subsequent degeneration of the distal part of the axon by disease or wilting of the nerve -Fibrillation occurs for several weeks and then ceases as the muscle cell atrophy -Not visible by naked eye -Seen in neurogenic and myogenic disease so to find out fibrillation we perform EMG 2-Fasciculation: -Contraction of group of muscle cells integrated by a single axon into a motor unit -Occurs when an anterior motor neuron is destroyed, as in motor neuron disease or the axon is severed -Visible by naked eye -Only seen in neurogenic disease Diagnostic Aids Diagnostic Aids Part 3 Part 3 {Radiographs and Photographs {Radiographs and Photographs,, BMR and EMG BMR and EMG} } Dr. Mohammed Alruby Dr. Mohammed Alruby