external anal sphincter
The Sphincter ani externus (external anal sphincter) is a flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus. [WP,unvetted]. Every claim on this page comes from the Leumas anatomy graph and carries its source.
What the external anal sphincter is
The Sphincter ani externus (external anal sphincter) is a flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus. [WP,unvetted]. The atlas records it as a muscle at the organ scale in the human body.
Where the external anal sphincter is
It sits in the pelvis and trunk, within the muscular system. Not positioned individually. Drawn inside the structure this dataset says contains it — the containment is asserted, the exact spot within it is not.
What the external anal sphincter connects to
The atlas records 10 typed relationships for it, across 4 kinds of connection. part of anal part of perineum, musculature and musculature of trunk, and 2 more.
Supply and innervation
This dataset asserts no arterial supply, venous drainage or innervation for the external anal sphincter. Only a minority of structures carry those edges here, so an empty answer means nothing has been recorded — not that there is nothing to record.
Also called
Also recorded as external sphincter ani, musculus sphincter ani externus and sphincter ani externus. Searching any of those names reaches this page.
Source
Uberon multi-species anatomy ontology (Mungall et al.), CC BY 4.0. Term UBERON:0001367, version 2026-06-19, retrieved 2026-08-24. Licence: CC-BY-4.0.
- Part of: anal part of perineum, musculature, musculature of trunk, organism subdivision and trunk.
- A kind of: muscle of anal triangle, skeletal muscle tissue and sphincter muscle.
- surrounds: anus.
- Continuous with: bulbospongiosus muscle.
Questions
Where is the external anal sphincter?
It sits in the pelvis and trunk, within the muscular system. Not positioned individually. Drawn inside the structure this dataset says contains it — the containment is asserted, the exact spot within it is not.
What does the external anal sphincter connect to?
Part of: anal part of perineum, musculature, musculature of trunk, organism subdivision and trunk.
Is the external anal sphincter the same in other species?
Leumas holds the same relationship vocabulary for every species it carries, so where another dataset records this structure you can put the two side by side on /compare.