OBO ID: GO:0097227

Term Name:	sperm annulus		Search Ontology:
Synonyms:
Definition:	The ring-like, filamentous structure located at the distal end of the midpiece of the sperm flagellum; the annulus is thought to form a diffusion barrier between the midpiece and the principal piece and serve as a stabilizing structure for tail rigidity.
References:
Ontology:	GO: Cellular Component    QuickGO    AmiGO