[The phenomenon of coiled spermatozoan tail]

The phenomenon of tail coiling in human spermatozoa is demonstrated by means of some clinical cases. The coiling of the free tail below the head is differentiated from the coiling of the axonema around the head and within a cytoplasmic droplet. The first phenomenon is caused probably by exogenous factors outside the testes such as pH-value and chemical constitution of the fluids in the seminiferous pathway; the latter may be caused genetically. The morphological alterations concern mainly the axonema in the tail and the organization of the middle piece and the head. Possible causes for the symptom of the coiled tail in spermatozoa are discussed.