Introduction Spermatogenesis Maturation of Spermatozoa in Epididymis Staining Techniques and Evaluation of Morphology Section I - Head abnormalities 1. Pyriform and tapered head 2. Nuclear vacuolation, including the diadem defect 3. Macrocephalic and microcephalic sperm 4. Rolled Head - Nuclear Crest - Giant Head Syndrome 5. Abnormal DNA condensation 6. Acrosome abnormalities 7. Normal detached heads and free abnormal heads 8. Decapitated sperm defect Section II -- Midpiece abnormalities 9. Proximal cytoplasmic droplet 10. Pseudodroplet 11. Mitochondrial sheath defect 12. Corkscrew sperm defect 13. Dag defect 14. Distal midpiece reflex 15. Bowed midpieces 16. Distal droplets 17. Abaxial midpieces Section III -- Tail (Principal piece) abnormalities 18. Tail stump defect 19. Coiled principal pieces 20. Double forms and accessory tails 21. Bent principal pieces 22. Short tail defect Section IV - aberrations of stains and other cells in the ejaculate 23. Aberrations due to staining 24. Aberrations due to cold shock 25. Round cells in the ejaculate 26. Teratoids 27. Medusa cells 28. Aberrations of semen quality