head cap


ac·ro·some

(ak'rō-sōm), A caplike organelle or saccule derived from Golgi elements that surround the anterior two thirds of the nucleus of a sperm. Enzymes contained within this structure probably facilitate the sperm's penetration of the zona pellucida of the oocyte. Synonym(s): acrosomal cap, head cap [acro- + G. soma, body]

head cap

(hed kap) A device fitted closely to the skull; used for fixed anchorage in external traction.