forearm
Enable an AI agent to recognise a forearm, record its structure and functional state, and determine which observations or actions are appropriate given the evidence and constraints.
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.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise a forearm, record its structure and functional state, and determine which observations or actions are appropriate given the evidence and constraints.
The forearm (antebrachium) is the tetrapod upper-limb segment between the elbow and the wrist, organised around the paired radius and ulna, the interosseous membrane, and the flexor and extensor compartments that produce pronation, supination, and the distal actions of wrist and hand.
It can be Locate, label and compare corresponding forearm regions using explicit landmarks.; Record dimensions, surface observations and reported symptoms with their methods and times.; Observe permitted pronation, supination and task performance under documented conditions.; Assess geometric compatibility with sleeves, braces or equipment without inferring clinical suitability.; Identify whether contact, movement or loading is supported by documented restrictions and authorisation.; Route uncertain or concerning observations for qualified assessment without assigning an unsupported diagnosis..
Distinguishing features
Locate the region between the elbow and wrist; a region between shoulder and elbow is the upper arm.
Check whether the referent denotes the complete bodily region rather than only the radius, ulna or an individual muscle.
Distinguish the forearm from the hand by identifying the wrist boundary under the chosen anatomical convention.
Resolve whether the referent is living anatomy, a detached specimen, a representation or an artificial replacement before applying biological state characteristics.
Scope
+ Identification, laterality and attachment to a particular body
+ Regional boundaries and the arrangement of bones, muscles, tendons and other tissues
+ Forearm rotation and contributions to wrist, finger and load-bearing tasks
+ Regional appearance, symptoms, tissue integrity and functional limitations
+ Local supports, exposures and constraints on examination, movement or contact
- Whole-person identity, general health and systemic diagnoses
- Upper-arm anatomy and shoulder mechanics
- Complete elbow and wrist joint models beyond their forearm interfaces
- Hand and finger anatomy beyond their functional connections to forearm tissues
- Detailed models of individual bones, nerves, vessels or muscles
- Prosthetic-device engineering and independent treatment protocols
Characteristics
- Body association and laterality
- Associated body identifier; left, right, indeterminate or not applicable Prevents observations or actions from being assigned to the wrong limb or individual.
- Biological and referent context
- Species; living attached anatomy, detached specimen, representation or artificial replacement Determines which structural expectations and permitted actions apply.
- Boundary convention
- Named convention with proximal and distal landmarks and included interface tissues Makes regional observations and measurements comparable.
- Regional dimensions
- Length and circumference in mm or cm, with landmarks, posture and measurement method Supports fit assessment and comparison of size or swelling over time.
- Structural configuration
- Documented continuity, alignment, tissue differences and surgical alterations; unknown where unassessed Prevents typical anatomy from being assumed when the actual configuration differs.
- Rotational position and movement
- Pronation and supination in degrees relative to a stated reference, with active or passive method Records forearm orientation and movement limitations without confusing them with shoulder or wrist motion.
- Task-specific load tolerance
- Force in N or supported mass in kg, duration in s, task, posture and observed response Connects functional capacity to the conditions under which it was observed.
- Regional symptoms and signs
- Located pain, swelling, skin changes, altered sensation or other observations; onset, severity, evidence source and assessment status Supports change detection while keeping reports and observations distinct from diagnoses.
- Supports and access constraints
- Linked cast, splint, brace, dressing or access device; location, coverage and documented restrictions Explains limits on inspection, movement, contact and loading.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 29 questions.
Forearm identity and boundaries Establishes which forearm is represented and where its regional ownership begins and ends.
Laterality errors and inconsistent elbow or wrist boundaries can invalidate otherwise accurate records.
Body and side
Connects the forearm to its biological context and referent.
Identified forearm
Records the associated body, side, species and whether the referent is actual anatomy or a substitute.
- Which body and side does this forearm belong to, and how was that association established? provenance
- Does the referent denote living anatomy, a specimen, a representation or an artificial replacement? definition
Regional limits
Defines the elbow and wrist interfaces used by this record.
Landmark-based extent
Makes proximal, distal and surface boundaries explicit without absorbing neighbouring joint models.
- Which landmarks delimit this forearm proximally at the elbow and distally at the wrist? boundary
- Which tissues at those interfaces are owned here, and which are represented through linked elbow, wrist or hand models? boundary
Regional anatomy and geometry Records the actual structural configuration and measurable shape of the forearm.
Forearm recognition, equipment fit and interpretation of movement depend on both internal configuration and external geometry.
Tissue arrangement
Locates regional structures and records known departures from expected anatomy.
Documented structural configuration
Links evidence about bones and soft tissues while keeping unobserved anatomy explicitly unassessed.
- What evidence establishes the presence, continuity and alignment of the radius, ulna and relevant regional soft tissues? provenance
- Which anatomical variations, injuries or surgical alterations change the expected arrangement in this forearm? definition
External geometry
Captures dimensions and surface locations in a reproducible frame.
Reproducible forearm measurements
Associates length, circumference and local shape with landmarks, orientation and method.
- What are the measured length and circumferences, and at which landmarks and limb posture were they obtained? measurement
- How are local observations positioned along the forearm and on its radial, ulnar, anterior or posterior aspects? measurement
Rotation and functional contribution Records forearm rotation and its contribution to tasks involving the wrist, hand and external loads.
Forearm function cannot be judged from appearance or a single strength value, and neighbouring movements can obscure limitations.
Pronation and supination
Describes rotational position, available movement and conditions of observation.
Observed rotation
Records rotation with reference position, method and any accompanying symptoms or compensatory movement.
- What pronation and supination were observed, using which reference position and active or passive method? measurement
- What elbow position, shoulder movement, pain or external support affected the observation? measurement
Task and load response
Connects forearm performance to specific hand, wrist and support tasks.
Contextual functional capacity
Records task performance without treating a whole-limb result as an isolated forearm measurement.
- During which permitted gripping, wrist-motion or support task was performance observed, and with what load, posture and duration? measurement
- What evidence attributes a limitation to the forearm rather than the hand, wrist, elbow, shoulder or overall effort? boundary
Regional condition and change Tracks local tissue condition, symptoms and changes that affect interpretation or action.
Similar forearm appearances can have different explanations, so condition records must preserve location, timing and evidence quality.
Surface and symptom map
Locates visible changes and reported experiences within the forearm.
Located condition observations
Separates observed skin or contour changes from reported pain and other symptoms.
- Where are wounds, bruising, swelling, contour changes or reported pain located relative to the forearm landmarks? measurement
- Which details were directly observed, reported by the person or copied from an assessment, and when? provenance
Sensory, circulatory and temporal context
Links relevant assessments and trends without deriving diagnoses from isolated signs.
Assessment and change record
Records available sensation and circulation assessments, including linked distal observations and changes from baseline.
- What documented assessments address sensation or circulation relevant to this forearm, and which observations belong to the linked hand model? provenance
- What has changed from a dated baseline, and were the comparison methods and conditions equivalent? measurement
- Does a documented care plan or applicable assessment protocol require these changes to be escalated? action
Forearm contact, support and restrictions Records how coverings, devices and explicit restrictions govern interaction with the forearm.
A cast, dressing, access site or movement restriction can change which forearm observations and actions are appropriate.
Attached and covering items
Maps supports and devices to the forearm regions they cover or affect.
Support and access map
Identifies casts, splints, braces, dressings and access devices together with their effects on visibility and movement.
- Which items cover, contact or enter the forearm, and where are their boundaries relative to the elbow and wrist? boundary
- What documented purpose and instructions accompany each item, and who supplied them? provenance
Permitted regional actions
Connects proposed examination, contact, rotation and loading to current permissions and restrictions.
Action-specific constraints
Records the basis for proceeding, modifying or deferring a particular interaction with the forearm.
- What current instructions and consent govern touching, measuring, rotating, loading or uncovering this forearm? action
- Which missing assessment, device instruction or restriction must be resolved before the proposed action can proceed? 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.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Human antebrachium as a regional anatomical unit
- Anterior (flexor-pronator) compartment
- Posterior (extensor-supinator) compartment
- Mobile wad of Henry (brachioradialis, extensor carpi radialis longus and brevis)
- Proximal forearm (around the proximal radioulnar joint and radial neck)
- Distal forearm (around the distal radioulnar joint and metaphyses)
- Osteological forearm (radius and ulna treated as one mechanical pair)
- Comparative forelimb zeugopodium in non-human tetrapods
- Which of these kinds and varieties hold for the sense of forearm this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Terminologia Anatomica 1998 - A01.1.00.024 - Antebrachium / forearm as a part of the human body.
- Foundational Model of Anatomy - FMA:9663 - Class Forearm.
- UBERON - UBERON:0002386 - Forelimb zeugopod / forearm, the multi-species anatomical class.
- MeSH - D005542 - Descriptor Forearm.
- SNOMED CT - 14975008 - Forearm structure (body structure).
- Which of these identifiers and schemes hold for the sense of forearm this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Terminologia Anatomica (TA2), term antebrachium - issued by FIPAT of the International Federation of Associations of Anatomists
- ICD-10 (and ICD-10-CM) category S52 Fracture of forearm - issued by the World Health Organization (national clinical modifications by CDC/NCHS and others)
- AO/OTA Fracture and Dislocation Classification, forearm diaphysis as bone 2 - issued by the AO Foundation and the Orthopaedic Trauma Association
- ISO 7250-1 Basic human body measurements for technological design - issued by the International Organization for Standardization
- ISO 22523 External limb prostheses and external orthoses - requirements and test methods - issued by the International Organization for Standardization
- Which of these standards and regulation hold for the sense of forearm this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Clinical examination and imaging of the radius, ulna, interosseous membrane, and distal radioulnar joint after trauma
- Radial-artery puncture for arterial-blood gas sampling and arterial-line placement; forearm veins used for cannulation when the cubital fossa is unavailable
- Harvest of the radial forearm free flap in reconstructive surgery
- Anthropometry for clothing, workstation reach, tool handles, exoskeletons and upper-limb prostheses
- Wearing surface for watches, fitness bands and some splints or orthoses
- Site of intramuscular or subcutaneous injection only in specific protocols; more often a landmark for compartment-pressure measurement
- Which of these real-world use hold for the sense of forearm this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Forearm length (radiale to stylion, adult humans) - 220-290 - mm
- Maximum forearm circumference (adult humans) - 230-340 - mm
- Active pronation from mid-position - 0-80 - degree
- Active supination from mid-position - 0-90 - degree
- Long bones in the segment - 2 (radius and ulna) - count
- Which of these typical measurements hold for the sense of forearm this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Diaphyseal fractures of radius, ulna, or both, with malrotation, shortening, or radioulnar synostosis
- Galeazzi, Monteggia and Essex-Lopresti fracture-dislocations that couple a forearm bone injury to a joint disruption
- Acute compartment syndrome, which can progress to Volkmann ischaemic contracture
- Injury or thrombosis of the radial or ulnar artery; injury of median, ulnar, radial or posterior interosseous nerves
- Chronic exertional compartment syndrome in athletes
- Cross-union or loss of pronation-supination after fixation or crush
- Which of these failure modes and hazards hold for the sense of forearm this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Lay English often uses "arm" for the whole upper limb; specialist English reserves "forearm" for the antebrachium and "arm"/"upper arm" for the brachium. Parallel everyday terms include German Unterarm, French avant-bras, Spanish antebrazo.
- Fracture talk still uses eponyms (Galeazzi, Monteggia, nightstick) in some centres and AO/OTA numeric codes in others; the same injury is therefore named differently in notes and registries.
- East Asian traditional-medicine practice maps forearm cun positions and meridians that do not coincide with the flexor/extensor compartment scheme.
- Which of these regional variation hold for the sense of forearm this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Arm (brachium) - The brachium is the segment that contains the humerus; it ends at the elbow joint, whereas the forearm begins distal to that joint and contains radius and ulna.
- Elbow (cubitus) - The elbow is a joint complex (humeroulnar, humeroradial, proximal radioulnar), not a limb segment; the forearm is the segment distal to it.
- Cubital fossa - The cubital fossa is the triangular anterior region of the elbow; it is a surface/landmark region at the boundary, not the forearm shaft.
- Wrist (carpus) - The wrist is the carpal complex distal to the radiocarpal joint; the forearm ends at that joint and does not include the carpal bones.
- Hand - The hand is distal to the carpus and contains metacarpals and phalanges; tendons that originate in the forearm insert there, but the hand is a separate segment.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of forearm this model covers, and on what evidence? provenance
Sources
- Gray's Anatomy: The Anatomical Basis of Clinical Practice - Regional definition of the antebrachium, radius-ulna osteology, compartments, nerves and vessels, and the elbow/wrist boundaries used in the definition, kinds, neighbours and hazards. Publisher: Elsevier (Standring, editor).
- Terminologia Anatomica - Official Latin/English nomenclature antebrachium/forearm and the TA identifier pattern. Publisher: FIPAT, International Federation of Associations of Anatomists.
- ICD-10, S52 Fracture of forearm - That the forearm is a coded injury region in international mortality/morbidity statistics, and the clinical grouping of radius and ulna shaft and end injuries. Publisher: World Health Organization.
- Fracture and Dislocation Classification Compendium - 2018 - How surgeons actually partition forearm injuries (diaphysis as bone 2; Galeazzi/Monteggia-type patterns under AO/OTA rather than as separate organs). Publisher: Journal of Orthopaedic Trauma / AO Foundation and Orthopaedic Trauma Association.
- ISO 7250-1: Basic human body measurements for technological design - Part 1: Body measurement definitions and landmarks - Anthropometric quantities (forearm length, forearm circumference) and the landmarking used in the measurements field. Publisher: International Organization for Standardization.
- A reference ontology for biomedical informatics: the Foundational Model of Anatomy - Canonical anatomy-ontology class for the forearm as a material anatomical entity, supporting the FMA identifier. Publisher: Journal of Biomedical Informatics (University of Washington FMA).
What the second pass must settle
- Does the registry intend forearm to cover human anatomy only, or also homologous regions in other species?
- Which anatomical boundary convention should govern ownership of tissues at the elbow and wrist interfaces?
- Should detached forearms and residual forearms remain instances of this model, and how should artificial replacements be linked to it?
- Which validated measurement methods and reference populations should support interpretation of dimensions, rotation and functional performance?
- Which authoritative assessment and device protocols should supply action restrictions and escalation criteria for each intended use context?