Sliding spermatozoa: a dyskinesia responsible for human infertility?

Microcinematographic analysis at 50 frames/second of motile spermatozoa from four sterile men, which were permanently unable to penetrate the cervical mucus or migrate through it was performed at ambient temperature. In all cases, we found the same abnormal pattern of movement, characterized by a very small amplitude of the periodic lateral displacement of the head and abnormal displacement of the wave along the flagellum. The results assessed the importance of normal sperm flagellar dynamics for fertility.