The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus
with highly compact CHROMATIN material.
http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=FR&Expert=171709 2011 France scientific and technical information sperm head
--- http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=FR&Expert=137893 2011 France scientific and technical information polyploidy sperm head infertility, male