Engel & Cunningham's Trichrome
for Muscle Fibres, Types I & II


Harris alum hematoxylin
Solution A
Chromotrope 2R 0.6 g
Fast green FCF 0.3 g
Phosphotungstic acid 0.6 g
Acetic acid, glacial 1 mL
Distilled water 99 mL
Adjust to pH 3.4 with 1N NaOH.
Solution B
Acetic acid, glacial 0.2 mL
Distilled water 100 mL

Tissue sample
Unfixed frozen sections of liquid nitrogen quenched muscle. Sections should be 5-10µ in thickness. The fibres should be in cross section, as close to a right angle to their length as possible.


  1. Cut cryostat sections and dry at room temperature.
  2. Stain nuclei with Harris' hematoxylin for 5 minutes.
  3. Rinse well with distilled water.
  4. Place into solution A for 10 minute.
  5. Rinse with solution B for a few seconds to differentiate.
  6. Dehydrate with ethanol.
  7. Clear with xylene and mount with a resinous medium.

Expected results


  1. Both fibre types are green overall, but type I fibres contain more red staining granular material and have a red cast.
  2. This is a modification of Gomori's trichrome.


Culling, C.F.A., Allison, R.T. and Barr, W.T.
Cellular Pathology Technique, Ed.4.
Butterworth, London, UK.
    Engel & Cunningham, (1963)
    Rapid examination of muscle tissue.
    An improved trichrome method for fresh frozen biopsy specimens.
    Neurology, vol.13, pp.921




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