A spermatozoon consists of four parts head, neck, middle piece and tail. Head is anterior, broad, flattened and oval part of human sperm. It consists of two parts, large posterior nucleus and a small anterior cap-like acrosome. The nucleus consists only of condensed DNA and basic proteins. Acrosome is narrow cap-like sac that covers about 2/3rd of head. It is derived from Golgi complex of the spermatid. Acrosome contains proteolytic and lysosomal enzymes popularly called sperm lysins, e.g.r hyalouronidase, corona penetrating enzyme, acrosin or zona lysin. Sperm lysins are essential in fusion of sperm and ovum during fertilization event.