More than a quarter of a century after the publication of Dubowitz and Brooke's classic Muscle Biopsy; A Modern Approach in 1973, there seems to be a lingering confusion regarding the proper technique for freezing muscle biopsies, and whether or not enzyme activity will be preserved. I have worked with muscle from humans, dogs, and rodents in my quarter of a century in histology, and would like to address the proper technical procedure to follow to insure high quality sections.

The first step is to acquire tissue immediately after excision, as any delay may alter the morphologic and enzymatic characteristics. If there is a slight delay between excision and freezing, keep the tissue covered with a gauze moistened (not soaked) in normal saline.