The Trumorph® system: The new universal technique for the observation and analysis of the morphology of living sperm. [corrected].

Evaluation of sperm morphology is a fundamental component of semen analysis, but its real significance has been obscured by a plethora of techniques that involve fixation and staining procedures that induce artefacts. Here we describe Trumorph℗®, a new method for sperm morphology assessment that is based upon examination of wet preparations of living spermatozoa immobilized by a short 60°C shock using negative phase contrast microscopy. We have observed samples from five animals of the following species: bull, boar, goat and rabbit. In every case, all the components of the sperm head and tail were perfectly defined, including the acrosome and midpiece (in all its length, including cytoplasmic droplets). A range of morphological forms was observed, similar to those found by conventional fixed and stained preparations, but other forms were found, distinguishable only by the optics used. The ease of preparation makes it a robust method applicable for analysis of living unmodified spermatozoa in a range of situations. Subsequent studies on well-characterized samples are required to describe the morphology of potentially fertilizing spermatozoa.