external anal sphincter in dogs
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 dog.
Where the external anal sphincter is
It sits in the pelvis and trunk, within the muscular system. Only the region is known. The position shown is somewhere plausible inside it and nothing more.
What the external anal sphincter connects to
The atlas records 15 typed relationships for it, across 4 kinds of connection. part of anal region, anatomical structure and musculature, and 5 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 region, anatomical structure, musculature, musculature of trunk, organ and organism subdivision, and 2 more.
- A kind of: anal region skeletal muscle, anatomical structure, muscle organ, perineal muscle and skeletal muscle tissue.
- surrounds: anus.
- Continuous with: bulbospongiosus muscle.
Questions
Where is the external anal sphincter?
It sits in the pelvis and trunk, within the muscular system. Only the region is known. The position shown is somewhere plausible inside it and nothing more.
What does the external anal sphincter connect to?
Part of: anal region, anatomical structure, musculature, musculature of trunk, organ and organism subdivision, and 2 more.
Is the external anal sphincter the same in other species?
This page describes the dog. The human record of the same structure sits beside it on /compare, over one shared model rather than two atlases built separately.