| Namespace | MPheno.ontology | Obsolete | false |
| description | any structural anomaly of the unique cytoskeletal component in the principal-piece segment of the sperm flagellum which surrounds the axoneme and outer dense fibers and contains two longitudinal columns that are connected by closely organized semicircular transverse ribs; the fibrous sheath is believed to regulate the degree of flexibility, flagellar motion and shape of the flagellar beat during the lifespan of a sperm cell |
