rectum
Enable an AI agent to identify a rectum, record its anatomical and functional state, and determine which observations or proposed actions require further evidence or clinical assessment.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an AI agent to identify a rectum, record its anatomical and functional state, and determine which observations or proposed actions require further evidence or clinical assessment.
The rectum is the terminal portion of the large intestine immediately proximal to the anal canal, serving as a distensible reservoir for feces and participating in defecation.
It can be Locate a reported finding within the rectum using an explicit landmark and boundary convention.; Combine examination, imaging, endoscopic, physiological, and tissue observations while preserving their distinct evidential limits.; Compare rectal structure or function over time when methods and anatomical context are sufficiently comparable.; Separate rectal findings from anal, colonic, pelvic floor, and systemic explanations that require neighboring models.; Record proposed examinations or interventions together with their clinical purpose, authorization, and unresolved prerequisites..
Distinguishing features
In the human default context, the segment must be located between the sigmoid colon and anal canal; the boundary convention must be recorded when precise localization matters.
An observation in the rectum must be distinguished from an observation at the anus or within the anal canal, even when a report informally calls both areas rectal.
The anatomical segment must be distinguished from its contents: stool within the lumen is not rectal tissue.
The rectum is an organ part belonging to an individual organism, not an organism or taxon in its own right.
A surgically constructed reservoir or retained rectal remnant must be identified explicitly rather than assumed to be an intact native rectum.
Scope
+ Rectal identity, species context, and boundaries with the sigmoid colon and anal canal
+ Rectal wall, lumen, surrounding tissue interfaces, and anatomical relationships
+ Temporary storage of fecal contents, filling sensation, and contribution to defecation
+ Observed structural changes, symptoms localized to the rectum, and functional impairment
+ Evidence supporting rectal observations and constraints on examinations or interventions
- The whole organism, its taxonomy, and population conservation status
- The colon as a whole and upstream digestion
- The anal canal and anal sphincters as separately modeled structures
- Pelvic floor and nervous system structures beyond their relationships to rectal function
- Disease classifications, cancer staging systems, and treatment protocols
- Feces as an independently characterized biological material
Characteristics
- Host and anatomical context
- Individual organism reference; species; relevant developmental and surgical context Human anatomical assumptions may not transfer to other species or altered anatomy.
- Segment boundaries
- Named proximal and distal landmarks, boundary convention, and identification method Determines whether an observation belongs to the rectum or an adjacent segment.
- Longitudinal location
- cm from a specified landmark, with method and uncertainty Allows findings to be located without treating measurements from different reference points as interchangeable.
- Wall and lumen appearance
- Observed mucosal appearance, wall changes, narrowing, distension, discontinuity, or not assessed Separates directly observed structural features from inferred diagnoses.
- Luminal contents
- Observed stool, gas, fluid, blood, mucus, foreign material, mixed contents, or unknown Contents influence examination quality, distension, and interpretation of symptoms.
- Reservoir mechanics
- Volume in mL, pressure in a stated pressure unit, and derived compliance with test protocol Characterizes filling behavior while preserving dependence on the measurement method.
- Filling sensation and evacuation
- Reported or measured filling sensation, urgency, evacuation difficulty, incomplete emptying, or not assessed Links rectal function to experience without assuming the rectum alone causes an evacuation problem.
- Anatomical continuity
- Native continuity, diverted, retained remnant, anastomosed, partially resected, absent, or uncertain Changes how rectal identity, contents, function, and access should be interpreted.
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.rectum
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 17 findings · 27 questions.
Rectal identity and boundaries Establish which anatomical segment is being modeled and how its extent is determined.
Rectal terminology can obscure differences between species, adjacent bowel segments, and surgically altered anatomy.
Host and segment identity
Bind the rectum to an individual organism and its anatomical context.
Native or altered rectum
Determine whether the referent is an intact native segment, a remnant, or a differently constructed structure.
- Which individual and species does this rectum belong to? definition
- What operative history or anatomical evidence establishes whether native rectal tissue remains? provenance
Proximal and distal limits
Make the boundaries with sigmoid colon and anal canal explicit.
Boundary convention
Record the landmarks and convention used to assign tissue or findings to the rectum.
- Which landmarks define the proximal and distal limits in this record? boundary
- Could a different anatomical, imaging, or procedural convention place this finding in an adjacent segment? boundary
Rectal wall and pelvic relations Represent the rectal wall, lumen, and interfaces with surrounding pelvic structures.
A luminal observation, a wall abnormality, and an adjacent pelvic process require different interpretations.
Wall and lumen
Localize visible or measured changes within the rectal segment.
Structural observation location
Describe an observation by longitudinal position, circumferential location when available, and tissue depth supported by the method.
- Where is the observation relative to a named landmark, and how was that position measured? measurement
- Does the evidence concern luminal contents, mucosa, deeper wall, or tissue outside the wall? boundary
Surrounding pelvic interfaces
Identify relevant relationships to surrounding tissues without incorporating those structures into the rectum.
Adjacency and extension
Distinguish contact, compression, and suspected extension across anatomical interfaces.
- Which surrounding structures are relevant at the observed rectal level in this individual's anatomy? boundary
- What evidence distinguishes simple adjacency or external compression from involvement across the rectal wall? provenance
Rectal storage and evacuation Represent filling, reservoir behavior, sensation, and rectal participation in evacuation.
Rectal function depends on both local properties and coordination with neighboring muscular and neural systems.
Filling and reservoir response
Characterize contents, distension, and responses to filling.
Contents, mechanics, and sensation
Keep observed contents, mechanical measurements, and reported sensations distinct but related.
- What contents or distension were observed, and under what preparation or testing conditions? measurement
- If filling pressure, volume, or sensory thresholds were measured, what protocol and units were used? measurement
Evacuation coordination
Relate rectal emptying to anal outlet, pelvic floor, and neural coordination.
Emptying and functional attribution
Record evidence of emptying difficulty without assigning all dysfunction to the rectum.
- What reported experience or observed test result supports incomplete or difficult rectal emptying? provenance
- Which aspects may arise from rectal properties, and which require anal outlet, pelvic floor, or neurological assessment? boundary
Rectal condition and change Track rectal abnormalities, associated symptoms, and changes over time.
Symptoms do not establish a rectal diagnosis, and apparent change may reflect different observation methods.
Observations and clinical interpretation
Separate symptoms and visible features from diagnostic conclusions.
Finding versus diagnosis
Represent bleeding, mucus, pain, urgency, lesions, or other abnormalities with explicit attribution and uncertainty.
- What was directly observed or reported, and what interpretation was added by a clinician or report? provenance
- What evidence localizes the symptom or abnormality to the rectum rather than another gastrointestinal or pelvic structure? boundary
Longitudinal comparison
Compare rectal observations across time and changes in anatomical context.
Comparable change
Determine whether recorded differences support actual structural or functional change.
- Were the same rectal location, measurement method, and preparation conditions used at each observation? measurement
- What intervening surgery, diversion, treatment, or other documented event changes the interpretation of the comparison? provenance
Rectal assessment and action Connect unresolved rectal questions to appropriate evidence and review of proposed actions.
Different assessment methods answer different rectal questions, and invasive actions require individual clinical context.
Assessment evidence
Record what each examination or test actually establishes.
Method coverage and limits
Preserve the coverage and limitations of examination, endoscopy, imaging, physiological testing, and tissue sampling.
- Which method produced this observation, and which rectal region or property did it assess? provenance
- Was any region inadequately visualized, unsampled, inaccessible, or outside the method's capabilities? boundary
Proposed procedures and review
Represent the purpose and prerequisites of actions involving the rectum.
Action context and prerequisites
Associate a proposed rectal examination, sampling procedure, or intervention with its intended question and responsible clinical review.
- What specific unresolved rectal question or clinical objective would the proposed action address? action
- What individual anatomical considerations, consent, and clinician assessment are required before proceeding? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This description assumes human anatomy; the term also occurs in comparative animal anatomy.
- Rectal boundary definitions differ between anatomical, endoscopic, imaging, and surgical contexts; verify the convention before comparing lengths or lesion locations.
- The length range is an approximate adult anatomical value recalled without source verification.
- Which of these check these first hold for the sense of rectum this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Terminologia Anatomica - Rectum - Latin anatomical term; the anal canal is separately named.
- Which of these identifiers and schemes hold for the sense of rectum this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- Terminologia Anatomica, maintained by the Federative International Programme for Anatomical Terminology (FIPAT), standardizes anatomical naming.
- Which of these standards and regulation hold for the sense of rectum this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Temporary storage of feces before defecation.
- Distension supplies sensory input involved in the urge to defecate and coordinated evacuation.
- Anatomical site for digital examination, endoscopy, and tissue sampling.
- Route for administration of suppositories and enemas.
- Which of these real-world use hold for the sense of rectum this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Adult human rectal length - Approximately 12-15 - cm
- Which of these typical measurements hold for the sense of rectum this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Rectal cancer.
- Proctitis, or inflammation of the rectal lining.
- Rectal prolapse.
- Fecal impaction.
- Traumatic or iatrogenic injury, including perforation.
- Which of these failure modes and hazards hold for the sense of rectum this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- sigmoid colon - The sigmoid colon lies immediately upstream; the rectum begins at the rectosigmoid junction.
- anal canal - The anal canal extends downstream from the anorectal junction to the anus and has distinct epithelial and sphincter relationships.
- anus - The anus is the external opening of the digestive tract, rather than the internal rectal reservoir.
- large intestine - The large intestine is the larger anatomical whole of which the rectum is a part.
- mesorectum - The mesorectum is the surrounding fatty connective tissue containing vessels, lymphatics, and nodes, rather than the rectal bowel wall or lumen.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of rectum this model covers, and on what evidence? provenance
What the second pass must settle
- Should this registry entry cover recta across animal species, and which comparative anatomical criteria establish the intended scope?
- Which authoritative boundary conventions should the model support, and how should conflicting anatomical, imaging, and procedural localizations be reconciled?
- Which reference ranges for rectal dimensions, mechanics, and sensation are defensible for particular populations and test protocols?
- How should retained rectal remnants, diverted recta, and surgically constructed reservoirs link to this entry without conflating distinct anatomical identities?
- Which existing Vercy models own the anal canal, sigmoid colon, pelvic floor, and rectal disease concepts, and does an existing world model already cover this anatomical segment?