0. S. WAR DEPT. TECHNICAL MANUAL 8-350 
TECHNIQUE OF MEDICAL DIATHESMI TPIY1 ffl 
WAR DEPARTMENT TECHNICAL MANUAL 
TECHNIQUE OF 
MEDICAL 
DIATHERMY 
7AR DEPARTMENT • NOVEMBER 1044 WA R DEPARTMENT TECHNICAL MANUAL 
TM 8-350 
TECHNIQUE OF 
MEDICAL 
DIATHERMY 
O O 5 ° 0 ’ 
WAR DEPARTMENT • 15 NOVEMBER 1944 
For sale by Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. 
United States Government Printing Office 
Washington : 1944 WAR DEPARTMENT, 
Washington 25, D. C., 15 November 1944. 
TM 8—350, Technique of Medical Diathermy, is published for the infor- 
mation and guidance of all concerned. 
[A.G. 300.7 (12 Jul 44).] 
By order of the Secretary of War: 
G. C. MARSHALL, 
Chief of Staff. 
Official: 
J. A. ULIO, 
Major General, 
• The Adjutant General. 
Distribution : 
Named Gen Hosp (12); Sta Hosp, Z. I. (6); Numbered Gen 
Hosp, T/O 8-550 (12) ; Numbered Sta Hosp, T/O 8-560 (6). 
For explanation of symbols, see EM 21-6. CONTENTS 
Paragraphs Page 
SECTION I. GENERAL 1 1 
II. PRINCIPLES IN THE USE OF HEAT 2-5 2 
III. DIATHERMY SERVICE 6-9 3 
IV. PRACTICAL APPLICATION Fig. 6®-32(D 10 SECTION I 
GENERAL 
1. PURPOSE AND SCOPE. The purpose of this manual is to provide a 
handy text illustrating the more frequent uses of medical diathermy as 
applied by coil and disc technique. Pathological indications relating to 
medical diathermy are not presented in this manual. For such information 
the reader is referred to standard texts on physical therapy. 
1 SECTION II 
PRINCIPLES IN THE USE OF HEAT 
2. GENERAL. Heat, administered by various methods, is accepted as a 
valuable therapeutic agent in many conditions. Medical diathermy applies 
heat usually by means of the coil or disc technique. Generally mild heat, 
or heat of moderate intensity over a longer period is as effective and is 
better tolerated than Intense heat for shorter periods. 
3. PHYSIOLOGIC EFFECTS, a. Heat will accomplish two physiological 
effects: 
(1) An increase in blood supply to the part. 
(2) Relaxation of muscle spasm, which will frequently relieve pain, 
b. Caution. Heat should never be used where an increase in blood would 
be detrimental as in acute trauma during the first 48 hours when there may 
be a chance of further local hemorrhage, or where there is bleeding into 
the tissues. Diathermy can generally be safely started after 48 hours in 
traumatic cases, thus hastening resolution of hemorrhage and giving an 
earlier and more complete recovery with less fibrous organization of the 
exudate. It should not be used in any case where there is organic or func- 
tional inability on the part of the circulation to increase in response to heat. 
Great caution should also be exercised in treating anesthetic regions, or 
injuries which may be complicated by vascular or neurovascular changes. 
The occurrence of increased pain, or the appearance of pain in non-painful 
areas is to be regarded as an absolute indication for the immediate reduction 
in intensity of the application. If pain persists after the reduction of intensity 
it is well to consider the discontinuance of treatment with diathermy. 
4. SPHERE OF APPLICATION. Medical diathermy may be used with 
benefit wherever there is deep seated inflammation or tissue repair in progress 
so long as caution, particularly those noted in paragraph 3b, is exercised. 
It is well to bear in mind that inflamed tissues, due to the presence of 
edema, are more readily overheated than normal tissues. It is essential, 
therefore, that only moderate heat be induced in inflamed tissues. A prac- 
tical way of accomplishing this is to start the treatment with an intensity 
sufficiently great that the patient states that he feels considerable heat, then 
IMMEDIATELY turn down the intensity to two-thirds or even to one- 
half the original setting. 
5. FREQUENCY AND LENGTH OF TREATMENT. The frequency and the 
length of the treatments must be determined in each case with due regard 
to the pathologic process involved. It may be stated in general that where 
there is acute inflammation the treatments should be mild and frequently 
repeated, whereas, in the treatment of simple muscle sprains they may be 
of greater intensity and at less frequent intervals. 
2 SECTION II! 
DIATHERMY SERVICE 
6. GENERAL, a. Modern diathermy machines have treatment cables (coil) 
and treatment drums (disc) which make use of the principle of inducing 
heat in tissue due to the presence of an electromagnetic field. It may be 
stated that in the average machine a current of about 7000 to 8000 volts 
changing direction of flow at the rate of 12 to 24 million times a second 
is generated. It is this current running through the treatment coil or disc 
which sets up the electromagnetic field (figs. 1, 2, 3, 4, and 5). 
b. Electromagnetic field. Eddy currents, set up in the tissue by the 
presence of the electromagnetic field, heat the tissues in direct proportions 
to the conductivity of the tissues, providing there is adequate spacing of the 
coil or disc from the skin. 
7. FUNDAMENTALS OF DIATHERMY APPLICATION, a. General. It is 
not the purpose of this manual to set forth the specific technique of setting 
the intensity controls for any given piece of apparatus. Specific instructions 
on the operation of the machine are furnished by the manufacturer. How- 
ever, when moderate heat is called for, this is approximately one-half the 
maximum intensity. Mild heat is approximately one-third the maximum 
intensity setting. 
b. Metallic objects will heat up quickly in the electromagnetic field, 
therefore, metal bracelets or wrist watches should be removed. Fillings in 
the teeth and other buried metals may not cause difficulties, if low intensity 
treatments or “indirect exposures” are administered in such cases. However, 
in the presence of metal bone-plates, this practice is not approved because 
of possible tissue damage which may result. FIGURE 1. COIL, 3 SPACERS, RUBBER CUFF. 
4 a. Rubber insulation. 
b. Woven copper conductor. 
c. Sash-cord center. 
FIGURE 2. CROSS-SECTION OF COIL 
SHOWING FROM WITHOUT IN. FIGURE 3. SCHEMATIC REPRESENTATION OF ELECTRO- 
MAGNETIC FIELD IN VICINITY OF COIL (3 turns). 
(Heavy black circles represent coil). FIGURE 4. TREATMENT DISC (DRUM). FIGURE 5. TREATMENT DISC (DRUM) WITH COVER 
REMOVED TO SHOW INTERIOR CONSTRUCTION. c. Adequate spacing from the skin is necessary to avoid too great a degree 
of skin heating. To obtain the desired spacing it is advisable to use air- 
spaced applicators (disc type) when possible so that spacing by towels or 
other absorbent materials may be unnecessary; evaporation of perspiration 
occurring in the open atmosphere. When using the coil it is necessary to 
utilize some absorbent material such as heavy dry towels to obtain the desired 
spacing. 
8. METHODS OF DIATHERMY APPLICATION. The following pages 
present an approved technique of diathermy application by means of coil 
and disc. For the sake of clarity it has often been necessary to show one 
or more preparatory stages for the treatment. It should be remembered that 
the last illustration in each case presents the final technique with all insula- 
tion in place. 
9. CAUTIONS, a. When using the coil it is necessary to make certain that 
the various turns of the coil do not come in contact with each other. For 
this purpose the manufacturers provide wooden or composition spacers to 
be placed between the turns to keep them at an even distance. The final 
turn of the coil, which leads to the machine, is spaced from the rest of the 
coil by a rubber cuff or by one or more felt spacers. 
b. In the application of diathermy to the head for whatever reason, it 
is advisable to insure adequate nasal drainage to avoid serious or annoying 
symptoms. The use of a vasoconstrictor, such as benzedrine inhalor, or a 
5 percent solution of some standard vasoconstrictor, and the prone position 
with the head over the edge of a table for a period of five minutes is recom- 
mended. SECTION IV 
PRACTICAL APPLICATION 
HEAD AND PARANASAL SINUSES 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses and metal 
neck chains). Insure adequate nasal drainage. 
FIGURE 6. RELATION OF DISC TO PART. HEAD AND PARANASAL SINUSES 
FIGURE 6. RELATION OF DISC TO PART- 
LATERAL VIEW—continued. 
Insulation: None. 
Intensity: Mild. 
Danger: Dizziness or headache, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Sitting when possible. 
11 HEAD AND PARANASAL SINUSES 
FIGURE 7. RELATION OF COIL TO PART. 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses and metal 
neck chains). Insure adequate nasal drainage. 
12 HEAD AND PARANASAL SINUSES 
FIGURE 7. RELATION OF COIL TO PART—continued. 
Insulation: One pillow or six thicknesses dry toweling. 
Intensity: Mild. 
Danger: Dizziness or pain, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Sitting, or side lying. HEAD AND PARANASAL SINUSES 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses and metal 
neck chains). Insure adequate nasal drainage. 
Insulation: None. 
Intensity: None. 
Danger: Dizziness or pain, treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Sitting if possible. 
FIGURE 8. RELATION OF DISC TO PART. 
14 NECK—POSTERIOR 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses, metal 
neck chains). 
Insulation: None. 
Intensity: Moderate to mild. 
Danger; Dizziness or pain, stop treatment. 
Duration : 30 to 60 minutes. 
Patient’s position: Sitting if possible. 
FIGURE 9. RELATION OF DISC TO PART. 
15 NECK—POSTERIOR 
i 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses, metal 
neck chains). Folded heavy towels in each axilla, or arms well separated 
from body. 
FIGURE 10. RELATION OF COIL TO PART. 
16 NECK—POSTERIOR 
FIGURE 10. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate to mild. 
Danger: Dizziness or pain, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Prone. Support head. NECK 
X 
FIGURE 11. RELATION OF COIL TO PART. 
Caution. Remove metallic objects (hair-pins, metal clasps, glasses, metal 
neck chains). Folded heavy towels in each axilla, or arms well separated 
from body. NECK 
FIGURE 11. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of dry heavy toweling. 
Intensity: Moderate to mild. 
Danger: Dizziness or pain, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Sitting if possible, or supine. SHOULDER AREA-ANTERIOR 
Caution. Remove metal neck chains. Folded heavy towels in each axilla, 
or arms well separated from body. 
FIGURE 12. RELATION OF COIL TO PART. 
20 SHOULDER AREA-ANTERIOR 
2 
FIGURE 12. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate to mild. 
Danger: Pain or deep muscle aching, reduce intensity, 
or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine. 
21 SHOULDER AREA—ANTERIOR 
FIGURE 13. RELATION OF DISC TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, 
or arms well separated from body. 
Insulation: None. 
Intensity: Moderate to mild. 
Danger: Pain or deep muscle aching, reduce intensity, 
or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine, or sitting. 
22 CHEST—ANTERIOR 
FIGURE 14. RELATION OF DISC TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, 
or arms well separated from body. 
Insulation: None. 
Intensity: Moderate. 
Danger: Palpitation or dyspnea, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine, 
23 CHEST—ANTERIOR 
1 
FIGURE 15. RELATION OF COIL TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, 
or arms well separated from body. CHEST—ANTERIOR 
FIGURE 15. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: Palpitation or dyspnea, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine. 
25 SHOULDER AREA—POSTERIOR 
FIGURE 16. RELATION OF COIL TO PART. 
Caution. Remove metal neck chain or hair-pins and metal clasps. Folded 
heavy towel in each axilla, or arms well separated from body. SHOULDER AREA—POSTERIOR 
2 
FIGURE 16. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate to mild. 
Danger: Pain or deep muscle aching, reduce intensity, 
or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Prone with pillow under chest. 
27 ARM AND SHOULDER AREA 
FIGURE 17. RELATION OF COIL TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, 
or arms well separated from body. Arm elevated on one or more pillows. ARM AND SHOULDER AREA 
FIGURE 17. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate to mild. 
Danger: Pain or deep muscle aching, reduce intensity, 
or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine with arm elevated on one or 
more pillows. 
29 CHEST—POSTERIOR 
FIGURE 18. RELATION OF COIL TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, 
or arms well separated from body. 
30 CHEST—POSTERIOR 
FIGURE 18. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: Palpitation or dyspnea, stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Prone. 
31 CHEST—POSTERIOR 
FIGURE 19. RELATION OF DISC TO PART. 
Caution. Remove metal neck chain. Folded heavy towel in each axilla, or 
arms well separated from body. A pillow under chest may add to the com- 
fort of patient. 
32 ABDOMEN—PELVIC AREA 
Caution. Folded heavy towel in each axilla, or arms well separated from 
body. Folded heavy towel in crotch or legs well separated. Folded towel 
over arm where cable crosses it. 
Insulation: None. 
Intensity: Moderate. 
Danger: Pain or cramps, reduce intensity or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine. 
FIGURE 20. RELATION OF DISC TO PART. 
33 ABDOMEN AND PELVIC AREA 
FIGURE 21. RELATION OF COIL TO PART. 
Caution. Remove metal belt buckle. Folded heavy towel in each axilla, or 
arms well separated from body. Folded towel over arm where coil crosses it. 
34 ABDOMEN AND PELVIC AREA 
FIGURE 21. RELATION OF COIL TO PART—continued 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: Pain or cramps, reduce intensity or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine. 
35 SPINE—LUMBOSACRAL AREA 
FIGURE 22. RELATION OF COIL TO PART. 
Caution. Remove metal buckle. Folded heavy towel in each axilla, or arms 
well separated from body. Folded heavy towel between legs. Pillow beneath 
chest and pelvis. SPINE—LUMBOSACRAL AREA 
2 
FIGURE 22. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. 
Duration: 45 to 60 minutes. 
Patient’s position: Prone. 
37 HIP—LUMBOSACRAL AREA—POSTERIOR 
i 
FIGURE 23. RELATION OF COIL TO PART. 
Caution. Remove metal buckle. Folded heavy towel in each axilla, or arms 
well separated from body. Folded heavy towel between thighs. Hip abdomen 
area on pillow. HIP—LUMBOSACRAL AREA—POSTERIOR 
FIGURE 23. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. 
Duration: 30 to 60 minutes. 
Patient’s position: Prone. 
39 BOTH HIPS AND LOWER SPINE AREA 
T 
FIGURE 24. RELATION OF COIL TO PART. 
Caution. Remove metal buckle. Folded heavy towel in each axilla, or arms 
well separated from body. Folded heavy towel between thighs. Hips and 
abdomen on pillow. BOTH HIPS AND LOWER SPINE AREA 
FIGURE 24. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. 
Duration: 30 to 60 minutes. 
Position: Prone. 
41 HIP AREA—LATERAL POSITION 
Caution. Remove metal buckle. Folded heavy towel in each axilla, or anus 
well separated from body. Folded heavy towel or pillow between thighs. 
Hip elevated on pillow. 
FIGURE 25. RELATION OF COIL TO PART. 
42 HIP AREA-LATERAL POSITION 
FIGURE 25—RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate, 
Danger: None. 
Duration: 45 to 60 minutes. 
Patient’s position: Semi-lateral, or lying on side. HIP—SCIATIC AREA-POSTERIOR 
Caution. Remove metal belt buckle. Folded heavy towel between thighs. 
Hips on pillow. 
FIGURE 26. RELATION OF COIL TO PART. HIP—SCIATIC AREA—POSTERIOR 
FIGURE 26. RELATION OF COIL TO PART—continued 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. 
Duration: 30 to 60 minutes. 
Patient’s position: Prone. 
45 KNEE AREA 
FIGURE 27. RELATION OF COIL TO PART. 
Caution. Remove metal sock holder. Folded heavy towel between thighs, 
or legs well separated. Knee elevated on pillow. KNEE AREA 
FIGURE 27. RELATION OF COIL TO PART—continued. 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. 
Duration: 30 to 60 minutes. 
Patient’s position : Supine or sitting. THIG H—KN E E—FOOT 
FIGURE 28. RELATION OF COIL TO PART. 
Caution. Remove metal sock holder. Folded heavy towel between thighs, 
or legs well separated. Leg on pillow. THIGH—KNEE—FOOT 
FIGURE 28. RELATION OF COIL TO PART—continued 
Insulation: Six thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: None. Pain or deep muscle aching, reduce 
intensity or stop treatment. 
Duration: 30 to 60 minutes. 
Patient’s position: Supine, Leg on pillow. PROSTATE-PERINEUM AREA 
FIGURE 29. RELATION OF COIL TO CHAIR. 
Caution. Twelve thicknesses of heavy dry toweling between chair and 
coil. Remove any metal connections to chair. PROSTATE—PERINEUM AREA 
FIGURE 30. RELATION OF COIL TO TOWELS AND CHAIR. 
Insulation: Six thicknesses of heavy dry toweling over coil. Use 
more if there is wasting of buttock muscles. PROSTATE—PERINEUM AREA 
FIGURE 31. RELATION OF COIL AND INSULATION 
TO PART. 
Insulation: Six or more thicknesses of heavy dry toweling. 
Intensity: Moderate. 
Danger: Abdominal cramps or desire to urinate, stop treatment. 
Duration: 60 minutes. 
Patient’s position: Sitting. VASODILITATION OF LOWER EXTREMITIES 
FIGURE 32. RELATION OF DISC TO PART FOR REFLEX 
VASODILITATION. 
Caution. Remove all metal parts. Wrap both lower extremities with single 
towels. Comforter beneath legs as shown. Folded towel between thighs. 
Folded towel on arm where cable crosses it. 
53 VASODILITATION OF LOWER EXTREMITIES 
FIGURE 32. RELATION OF DISC TO PART—continued 
Insulation: None under disc. 
Intensity: Moderate. 
Danger; Abdominal cramps, reduce intensity or stop treatment. 
Duration: 60 minutes. 
Patient’s position: Supine. 
54 
U. S. GOVERNMENT PRINTING OFFICE: 1944—616003