MSK
MSKSuite v0.1
Musculoskeletal ultrasound · calculator & decision support
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MSKSuite — MSK Ultrasound Decision Support

Ten-module hub covering nerve entrapment CSA, OMERACT synovitis + power-Doppler scoring, rotator cuff tear sizing, tendinopathy screening, muscle injury (BAMIC), joint effusion, POCUS rapid triage, dynamic maneuvers, and foundations/pitfalls. Numbers are guides — always correlate with symmetry, symptoms, and dynamic findings. Sono Sports Rheum POCUS

Nerve Entrapment — CSA Thresholds

Cartwright · Klauser · Hobson-Webb · El Miedany CSA measured inside the hyperechoic epineurium · continuous trace
Carpal tunnel median n. deep to flexor retinaculum CSA ≥ 10 mm² @ pisiform ΔCSA > 2 mm² · WFR ≥ 1.4 Cubital tunnel ulnar n. posterior to medial epicondyle medial epicondyle olecranon CSA > 9 mm² @ sulcus check dynamic subluxation in flex Fibular head (CPN) common peroneal · wraps fibula fibular head CSA 8–10 mm² entrapment compare contralateral · look for ganglion
Sites of peripheral nerve entrapment with transverse-plane CSA thresholds. Thresholds are guides, not absolutes — body habitus and pre-existing polyneuropathy shift baselines; symmetry with the contralateral side is the single most useful sanity check.

Inputs

Decision

Enter values to evaluate.
Cutoff @ site: — ΔCSA: — WFR: —

OMERACT Synovitis — Greyscale + Power Doppler

Szkudlarek 2003 · OMERACT 2017 combined score Score each joint 0–3 grey-scale + 0–3 Doppler
GREYSCALE (GS) GS 0 — normal GS 1 — minimal GS 2 — moderate GS 3 — marked + distension POWER DOPPLER (PD) — PD 0 — no flow PD 1 — isolated signals PD 2 — confluent <50% PD 3 — confluent >50%
OMERACT combined score: both axes graded 0–3 per joint. Use minimal pressure (probe float) and lowest wall-filter / PRF your machine allows before calling Doppler. Always set the color box to sit deep to the synovium so you don't miss deep-seated flow.

Inputs

Score & interpretation

Select scores.
Combined: 0 EULAR-OMERACT activity tier: —
Doppler trumps greyscale for disease activity. PD ≥ 2 in a symptomatic joint = active synovitis regardless of GS. Treat-to-target follow-up: re-image at the same depth / gain / PRF.

Rotator Cuff — Tear Sizing

Gartsman / DeOrio · ESSR consensus Measure AP (sagittal) × ML (long-axis) in cm
Small < 1 cm Medium 1–3 cm Large 3–5 cm Massive ≥ 5 cm supraspinatus only supraspinatus full-thickness supra + infra partial ≥ 2 tendons · retraction
Categories are based on the greatest of AP (sagittal/coronal) or ML (longitudinal) diameter. Retraction to the glenoid and Goutallier fatty infiltration (MRI) trump US sizing when surgical planning.

Inputs

Category

Enter dimensions.
Describe tears as "full-thickness, AP × ML, [tendon(s)], retraction" — size alone is incomplete. Symmetric scanning (opposite shoulder) resolves 30 % of "is-this-a-tear" calls in the over-65 population.

Tendinopathy Screen

Achilles · patellar · plantar · common extensor/flexor Thickness (AP), echotexture, neovascularity (Öhberg)
Normal Hyperechoic · fibrillar · normal AP thickness < cut Tendinopathy Thickened · focal hypoechoic · neovascularity > cut Partial tear Anechoic cleft · retracted fibre ends · ± hematoma
The spectrum runs normal → tendinopathy → partial tear → full tear. Always rule out anisotropy (beam off-perpendicular makes fibrillar tissue look falsely dark) by rocking the probe — real disease persists, anisotropy vanishes. Öhberg neovascularity is strongly associated with pain, but asymptomatic neovascularity is common in athletes.

Inputs

Impression

Enter thickness.
AP thickness cutoffs (mid-substance): Achilles > 6 mm · patellar > 7 mm · plantar fascia > 4 mm · common extensor > 4.2 mm · common flexor > 4.5 mm. Always rule out anisotropy before calling "hypoechoic" — rock the probe, don't just press harder. Asymptomatic neovascularity is common in athletes, so Öhberg alone ≠ diagnosis.

Muscle Injury — BAMIC 2018

British Athletics MRI Classification · adapted for US Grade 0–IV · suffix a (myofascial) / b (musculotendinous) / c (intratendinous)
Grade 0 — DOMS Grade I — < 5 cm Grade II — < 15 cm Grade III — ≥ 15 cm Grade IV — complete intact architecture few fibres · small focus partial · discrete hematoma extensive architectural loss complete · retracted ends Suffix: a myofascial · b musculotendinous junction · c intratendinous (healing ~2× longer)
BAMIC combines grade (extent / length of disruption) with suffix (anatomic depth). Same grade, different suffixes = very different timelines: a grade IIa hamstring returns around 4–6 weeks; a grade IIc can take 12+ weeks.

Findings

BAMIC grade & return-to-play estimate

Select grade + depth.
RTP ranges are population averages — never give a date to an athlete. Intratendinous (c) lesions take ~2× longer than the same-grade myofascial (a) lesion.

Joint Effusion — Presence & Complexity

EULAR scanning protocol · compressible vs non-compressible Qualitative first · measure only if it changes management

Scan

Impression

Select character.
Millimeter cutoffs vary by joint, body habitus, and recess — the most useful single step is compare the contralateral side in the same plane. A hot joint with any effusion = tap-and-culture, not wait-and-watch.

POCUS Rapid MSK Triage

ED / sideline · 30-second yes/no questions Binary decision pathway · confirm with formal imaging

Pick a scenario

Disposition

Choose a scenario.
POCUS excludes/confirms — it does not replace a structured sonographic exam. If your POCUS is equivocal and the clinical picture is high-pretest-probability → escalate.

Dynamic Maneuvers — Cheat Sheet

What to move, what you're looking for Dynamic > static in 40 % of MSK complaints

Nerve CSA — Reference Card

Normal upper-limit CSA by site Compiled: Cartwright 2008/2012 · Klauser · Hobson-Webb · Visser

Foundations & Pitfalls

The six reasons MSK US calls are wrong Anisotropy · asymmetry · artifact · ambient · anatomy · attitude
MSKSuite v0.1 · single-file · vanilla JS · zero dependencies · SonoAtlas © — Thresholds from published guidance. Always correlate numbers with clinical context and bilateral symmetry.