What is the perivitelline space ?

The perivitelline space is the narrow region between the oocyte's plasma membrane (oolemma) and the surrounding zona pellucida.

This space is pivotal during fertilization and early embryogenesis, as it is where the sperm nucleus is deposited following membrane fusion or direct injection via ICSI.

The characteristics of the perivitelline space can influence oocyte activation and subsequent embryo quality.