Follicular antrum

{{Short description|Portion of an ovarian follicle filled with follicular fluid in mammals}}

{{Infobox anatomy

| Name = Follicular antrum

| Latin = antrum folliculare

| Image =

| Caption = Mature late-stage tertiary (Graffian) follicle.

| Image2 =

| Caption2 = Early folliculogenesis from primordial to early tertiary.

| Precursor =

| System =

| Artery =

| Vein =

| Nerve =

| Lymph =

}}

The follicular antrum is the portion of an ovarian follicle filled with follicular fluid. Appearance of the follicular antrum during follicular maturation is the first sign that a follicle has reached the next stage of maturation.