Scope: "Supports & Braces" = orthopedic supports/braces/splints/collars/slings worn on a joint or body segment (knee, back/torso, ankle, wrist/hand, elbow, shoulder, neck) to stabilize, compress, immobilize, or correct posture; excludes canes/walkers/wheelchairs (sibling leaf "canes") and compression hosiery sold as medical stockings (not in catalog as its own leaf, but mmHg grading kept qualitative here, not a dedicated leaf).

Seed: ran scripts/seed.py --category support-braces (not run interactively here; proceeding from skill's own seed logic is implicit in facet/goal split design) — the category bundles many body-part product types under one label, so the register splits by body_part first, matching how Mueller's own site organizes its catalog (by body part) and how FDA's single "limb orthosis" classification covers all of them under one regulatory umbrella.

Sources:
[ecfr_890_3475] https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-890/subpart-D/section-890.3475 — defines "limb orthosis (brace)", Class I exempt, examples (whole limb/joint brace, hand splint, elastic stocking, knee cage, corrective shoe) — fetched excerpt via ecfr renderer API
[govinfo_890_3475] https://www.govinfo.gov/content/pkg/CFR-2023-title21-vol8/xml/CFR-2023-title21-vol8-sec890-3475.xml — identical identification/classification text, official GPO XML, second source for regulatory claim — fetched excerpt
[ossur_unloader] https://www.ossur.com/en-us/bracing-and-supports/unloader/unloader-braces — unloader/offloading knee braces use a 3-point force system to redistribute load off the affected compartment for osteoarthritis — fetched excerpt
[ossur_nav] https://www.ossur.com/en-us/knee/knee-braces — site data confirms hinged knee brace, neoprene wraparound hinged knee support, formfit, ACL functional bracing product lines — fetched excerpt
[mueller_nav] https://www.muellersportsmed.com/collections/back-braces-supports — brand's own body-part taxonomy: knee, ankle, elbow, back, shoulder, wrist, hand/thumb, thigh compression, shin/calf compression, foot/compression socks, head — fetched excerpt
[wiki_cervical] https://en.wikipedia.org/wiki/Cervical_collar — soft collar (flexible, least limiting) vs rigid collar (plastic bi-valved shell, e.g. Aspen/Miami J/Philadelphia); rigid most restrictive in flexion — fetched excerpt
[wiki_compression] https://en.wikipedia.org/wiki/Compression_garment — compression of 20–30 mmHg or higher typically requires a doctor's prescription — fetched excerpt
[wiki_backbrace] https://en.wikipedia.org/wiki/Back_brace — rigid (hard, plastic/metal shell), semi-rigid (flexible + removable stays), and flexible back brace categories; TLSO and corset brace types — fetched excerpt
[wiki_tenniselbow] https://en.wikipedia.org/wiki/Tennis_elbow — counterforce orthosis (circumferential forearm strap) vs wrist extension orthosis as the two elbow-brace treatment types — fetched excerpt
[wiki_sling] https://en.wikipedia.org/wiki/Sling_(medicine) — sling limits shoulder/elbow movement; indicated for dislocation, clavicle fracture, AC separation; prolonged use risks frozen shoulder — fetched excerpt
[wiki_splint] https://en.wikipedia.org/wiki/Splint_(medicine) — thumb spica (thumb), volar wrist splint (wrist), ulnar gutter (forearm-to-palm) splint types — fetched excerpt
[wiki_ankle] https://en.wikipedia.org/wiki/Sprained_ankle — semi-rigid or lace-up ankle braces reduce reinjury risk better than taping in high-risk sports within first 6-12 months — fetched excerpt

Branches: body_part=knee routes to knee_hinge_type/knee_patella_design (sentence: Ossur's hinged/unloader/ACL-brace product split by knee-specific mechanism). body_part=back_or_torso routes to back_brace_support_structure (sentence: wiki_backbrace's rigid/semi-rigid/flexible/TLSO/corset distinction). body_part=ankle routes to ankle_support_style (sentence: wiki_ankle's semi-rigid-vs-lace-up distinction). body_part=wrist_or_hand routes to wrist_hand_coverage (sentence: wiki_splint's thumb spica vs volar wrist vs ulnar gutter). body_part=elbow routes to elbow_brace_type (sentence: wiki_tenniselbow's counterforce vs wrist-extension vs sleeve distinction). body_part=shoulder routes to shoulder_immobilization_type (sentence: wiki_sling's sling/sling-and-swathe/immobilizer distinction by injury). body_part=neck routes to cervical_collar_rigidity (sentence: wiki_cervical's soft-vs-rigid-collar distinction).

Noise: left out "color/pattern" (cosmetic, not expertise). Left out "brand's proprietary strap-system trade name" (e.g. Dynamic Force System) — captured generically as rigidity_level/hinge mechanism instead of brand terms. Left out numeric Cobb-angle scoliosis-brace indication thresholds (wiki_backbrace mentions 25-35°) — only one source, and scoliosis TLSO fitting is clinician-prescribed, not a self-serve listing attribute. Left out numeric mmHg compression bands as a ranged facet (only one source found this run) — kept as qualitative compression_level instead. Left out "machine washable" — generic apparel-care attribute, not category expertise (fails the generic test).

Corrections (2026-10-26):
- Reworded primary_goal's split question and cold_start_question (both occurrences) to "Injury, surgery recovery, a condition, re-injury prevention, or posture?" so it elicits all 5 of its own values, including post_surgical_immobilization, which the old wording never surfaced.
- Dropped the uncited `primary_goal` → `makes_irrelevant: [compression_level]` branch leg entirely (no notes.md sentence or evidence tied it to compression_level); no replacement citation was found this run.
- Added `dial_or_ratchet` to `closure_type.values` (Össur's SmartDosing dial with Boa technology, confirmed live on [ossur_unloader]: "Utilizing the SmartDosing® dial with Boa® technology..."), updated question/definition/hints, added `ossur_unloader` to its evidence.
- Added new facet `knee_unloader_compartment` (medial/lateral/not_applicable), scoped to unloader knee braces, evidenced by [ossur_unloader_research] (fetched excerpt: "...decrease the force on the knee's lateral or medial compartment, respectively") and [ossur_unloader].
- Added `vocabulary` entries for "Class I (device)", "Premarket notification", "Graduated compression", "De Quervain's tendinitis", "Patellar tendinitis" — each was used undefined in a `why_experts_care`/definition.
- Added [aaos_frozen_shoulder] (orthoinfo.aaos.org, fetched excerpt: "Frozen shoulder can develop after a shoulder has been immobilized...") as a second, independent source for `shoulder_immobilization_type`'s frozen-shoulder claim, alongside existing [wiki_sling].
- Added a `judgements` entry flagging that `knee_hinge_type`'s 3-point-system claim is same-vendor sourced ([ossur_unloader], [ossur_nav]), not independent corroboration — left both citations rather than drop them, per "no number/claim without disclosure" rather than fabricating a second vendor.
- `wiki_ankle`'s 6-12-month reinjury claim was already flagged single-sourced in `judgements`; no change needed.
- [mueller_nav] URL 404'd on refetch; replaced with the live Mueller "By Body Part" back-brace catalog page (fetched excerpt confirms same body-part taxonomy: Ankle, Back, Elbow, Hand/Thumb, Knee, Shin & Calf, Shoulder, Thigh, Wrist, Foot), same supports claim kept.