| Namespace | MPheno.ontology | Obsolete | false |
| description | any structural morphology of the ring-like portion of the manchette that surrounds the base of the elongating spermatid nucleus below the acroplaxome marginal ring and plays a key role in shaping the nucleus and the sperm head; microtubules extend from the perinuclear ring into the cytoplasm and/or basal body of the spermatid |