DiagnosticTree/FrontOfArm: Difference between revisions

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Line 751: Line 751:
     {
     {
       "id": "pw_brachialis_biceps",
       "id": "pw_brachialis_biceps",
       "pair": ["brachialis", "biceps"],
       "pair": [
        "brachialis",
        "biceps"
      ],
       "text": "Tiebreaker \u2014 Brachialis vs Biceps Brachii",
       "text": "Tiebreaker \u2014 Brachialis vs Biceps Brachii",
       "question": "Does elbow flexion pain differ between palm-up and palm-down positions?",
       "question": "Does elbow flexion pain differ between palm-up and palm-down positions?",
Line 775: Line 778:
     {
     {
       "id": "pw_scalene_scalenus_minimus",
       "id": "pw_scalene_scalenus_minimus",
       "pair": ["scalene", "scalenus_minimus"],
       "pair": [
        "scalene",
        "scalenus_minimus"
      ],
       "text": "Tiebreaker \u2014 Scalene vs Scalenus Minimus",
       "text": "Tiebreaker \u2014 Scalene vs Scalenus Minimus",
       "question": "Which arm symptom pattern dominates?",
       "question": "Which arm symptom pattern dominates?",
Line 799: Line 805:
     {
     {
       "id": "pw_subclavius_scalenus_minimus",
       "id": "pw_subclavius_scalenus_minimus",
       "pair": ["subclavius", "scalenus_minimus"],
       "pair": [
        "subclavius",
        "scalenus_minimus"
      ],
       "text": "Tiebreaker \u2014 Subclavius vs Scalenus Minimus",
       "text": "Tiebreaker \u2014 Subclavius vs Scalenus Minimus",
       "question": "Does arm abduction worsen the radial forearm and hand symptoms (Wright position), OR is the nocturnal arm pattern more prominent?",
       "question": "Does arm abduction worsen the radial forearm and hand symptoms (Wright position), OR is the nocturnal arm pattern more prominent?",
Line 823: Line 832:
     {
     {
       "id": "pw_infraspinatus_biceps",
       "id": "pw_infraspinatus_biceps",
       "pair": ["infraspinatus", "biceps"],
       "pair": [
        "infraspinatus",
        "biceps"
      ],
       "text": "Tiebreaker \u2014 Infraspinatus vs Biceps Brachii",
       "text": "Tiebreaker \u2014 Infraspinatus vs Biceps Brachii",
       "question": "Is the primary pain DEEP INSIDE the shoulder joint, OR is it a superficial surface ache over the anterior shoulder?",
       "question": "Is the primary pain DEEP INSIDE the shoulder joint, OR is it a superficial surface ache over the anterior shoulder?",
Line 847: Line 859:
     {
     {
       "id": "pw_supraspinatus_biceps",
       "id": "pw_supraspinatus_biceps",
       "pair": ["supraspinatus", "biceps"],
       "pair": [
        "supraspinatus",
        "biceps"
      ],
       "text": "Tiebreaker \u2014 Supraspinatus vs Biceps Brachii",
       "text": "Tiebreaker \u2014 Supraspinatus vs Biceps Brachii",
       "question": "Is there a painful arc between 60\u00b0 and 120\u00b0 of shoulder abduction, OR is the arm pain primarily at the anterior shoulder without an arc pattern?",
       "question": "Is there a painful arc between 60\u00b0 and 120\u00b0 of shoulder abduction, OR is the arm pain primarily at the anterior shoulder without an arc pattern?",
Line 871: Line 886:
     {
     {
       "id": "pw_sternalis_scalene",
       "id": "pw_sternalis_scalene",
       "pair": ["sternalis", "scalene"],
       "pair": [
        "sternalis",
        "scalene"
      ],
       "text": "Tiebreaker \u2014 Sternalis vs Scalene",
       "text": "Tiebreaker \u2014 Sternalis vs Scalene",
       "question": "Is the chest pain completely unaffected by any shoulder or arm movement, OR do arm or hand symptoms accompany it?",
       "question": "Is the chest pain completely unaffected by any shoulder or arm movement, OR do arm or hand symptoms accompany it?",
Line 895: Line 913:
     {
     {
       "id": "pw_triceps_trp5_brachialis",
       "id": "pw_triceps_trp5_brachialis",
       "pair": ["triceps_trp5", "brachialis"],
       "pair": [
        "triceps_trp5",
        "brachialis"
      ],
       "text": "Tiebreaker \u2014 Triceps Medial Head vs Brachialis",
       "text": "Tiebreaker \u2014 Triceps Medial Head vs Brachialis",
       "question": "Is the medial epicondyle the dominant distal referral, OR is the thumb base the dominant distal referral?",
       "question": "Is the medial epicondyle the dominant distal referral, OR is the thumb base the dominant distal referral?",
Line 986: Line 1,007:
       "id": "rf-e1",
       "id": "rf-e1",
       "label": "Acute coronary syndrome / cardiac ischaemia",
       "label": "Acute coronary syndrome / cardiac ischaemia",
       "question": "Cardiac emergency \u2014 the lead consideration whenever anterior-chest or left-arm pain is present. Central or left-sided chest pressure, tightness, heaviness, or constriction \u2014 often radiating to the inner (ulnar) arm, neck, or jaw \u2014 with diaphoresis, nausea, breathlessness, or pain at rest or on exertion? Sweating accompanying the chest pain is a strong predictor of myocardial infarction. Presentations are frequently atypical in women, the elderly, and people with diabetes (fatigue, breathlessness, epigastric or back pain, or no chest pain at all). The sternalis trigger-point pattern is an explicit CARDIAC MIMIC \u2014 a deep substernal ache that is movement-independent and may spread to the front of the shoulder and upper arm \u2014 and this model carries a 'during/after a cardiac event' onset path; crucially, reproduction or RELIEF of pain by trigger-point treatment does NOT exclude acute coronary syndrome. Establish cardiac status independently and without delay: 12-lead ECG within 10 minutes, serial troponins, and risk stratification before any musculoskeletal attribution. Left-sided anterior-chest pain is not myofascial until cardiac disease has been excluded.",
       "question": "Cardiac emergency \u2014 consider FIRST with any anterior-chest or left-arm pain. Central/left chest pressure or tightness radiating to inner arm, neck, or jaw, with sweating, nausea, breathlessness, or rest/exertional onset; often atypical in women, the elderly, and diabetics. Sternalis TrP mimics cardiac pain and TrP relief does NOT exclude ACS. 12-lead ECG within 10 min + troponins before any myofascial label.",
       "source": "Acute Coronary Syndrome StatPearls (NBK459157); Chest Pain: Evaluation and Exclusion of MI and Angina StatPearls (NBK557672); T&S (sternalis cardiac mimicry)"
       "source": "Acute Coronary Syndrome StatPearls (NBK459157); Chest Pain: Evaluation and Exclusion of MI and Angina StatPearls (NBK557672); T&S (sternalis cardiac mimicry)"
     },
     },
Line 992: Line 1,013:
       "id": "rf-e2",
       "id": "rf-e2",
       "label": "Acute compartment syndrome of the arm",
       "label": "Acute compartment syndrome of the arm",
       "question": "Surgical limb emergency. Severe upper-arm pain OUT OF PROPORTION to the apparent injury, worsening and unrelieved by analgesia, with PAIN ON PASSIVE STRETCH of the elbow and forearm (the earliest sign) and a tense, swollen, wood-like arm? Consider after humeral-shaft fracture, crush, vascular injury or reperfusion, a tight cast or splint, bleeding (anticoagulation, haemophilia), high-pressure injection, or intense eccentric exertion. The anterior arm compartment holds biceps and brachialis with the musculocutaneous nerve and the brachial artery, and the median, ulnar, and radial nerves traverse the arm \u2014 so this overlaps the biceps/brachialis flexion-load and acute-overstretch presentations the model scores. Pallor, pulselessness, paraesthesia, and paralysis are LATE. Confirm with compartment pressures if needed (delta-p within 30 mmHg of diastolic, or absolute >30 mmHg) but do not delay \u2014 fasciotomy within about 6 hours preserves the limb; later, irreversible muscle necrosis, contracture, and nerve loss follow.",
       "question": "Surgical limb emergency. Arm pain OUT OF PROPORTION, unrelieved by analgesia, worse on PASSIVE finger/elbow stretch (earliest sign), with a tense, swollen arm \u2014 after fracture, crush, tight cast, bleeding/anticoagulation, or hard exertion. Pulselessness, paraesthesia, and paralysis are LATE. Immediate surgical referral; fasciotomy within ~6 h.",
       "source": "Acute Compartment Syndrome StatPearls; Brukner & Khan Ch.18 [VERIFY against your Ch.18 copy + add exact StatPearls NBK id]"
       "source": "Acute Compartment Syndrome StatPearls; Brukner & Khan Ch.18 [VERIFY against your Ch.18 copy + add exact StatPearls NBK id]"
     },
     },
Line 998: Line 1,019:
       "id": "rf-e3",
       "id": "rf-e3",
       "label": "Septic glenohumeral arthritis",
       "label": "Septic glenohumeral arthritis",
       "question": "Joint emergency \u2014 rapidly progressive, irreversible cartilage destruction if untreated. Acute, severe, constant deep shoulder-joint pain with pain on ALL movement (active AND passive) out of proportion to any mechanical history, often with joint swelling, warmth, or erythema? Joint pain (~85%) and swelling (~78%) are the most sensitive features; FEVER IS ABSENT OR ONLY LOW-GRADE IN MANY \u2014 reported in only ~17\u201342% of glenohumeral cases \u2014 so a normal temperature does NOT exclude it. Higher risk with diabetes, immunosuppression, intravenous drug use, recent intra-articular injection or procedure, rheumatoid or prosthetic joints, or bacteraemia. It mimics rotator cuff disease, adhesive capsulitis, and calcific tendinitis, but the pain is out of proportion and unremitting. This overlaps the 'deep inside the joint' presentation the model attributes to infraspinatus \u2014 deep, constant, fever-or-risk-factor-flagged joint pain must be triaged for infection FIRST. Urgent inflammatory markers (WBC, ESR, CRP) and joint aspiration (Gram stain and culture is the gold standard); treatment is prompt drainage plus IV antibiotics.",
       "question": "Joint emergency \u2014 rapid cartilage destruction. Acute, constant, severe deep shoulder pain with pain on ALL movement (active AND passive), often warm or swollen. Fever may be absent or low-grade (only ~17\u201342% of cases) \u2014 a normal temperature does NOT exclude it. Risk: diabetes, immunosuppression, IV drug use, recent injection, prosthesis, bacteraemia. Urgent WBC/ESR/CRP + joint aspiration; drainage + IV antibiotics.",
       "source": "Evaluation and Management of Septic Arthritis in the ED (PMC6404712); Septic Arthritis of the Glenohumeral Joint (PubMed 9653429); Septic Arthritis evidence-based review (AJR 2021, AJR.20.22773)"
       "source": "Evaluation and Management of Septic Arthritis in the ED (PMC6404712); Septic Arthritis of the Glenohumeral Joint (PubMed 9653429); Septic Arthritis evidence-based review (AJR 2021, AJR.20.22773)"
     }
     }
Line 1,006: Line 1,027:
       "id": "rf-u1",
       "id": "rf-u1",
       "label": "Posterior glenohumeral dislocation",
       "label": "Posterior glenohumeral dislocation",
       "question": "Easily missed and frequently overlooked on the AP radiograph. After a seizure, electric shock, or a fall onto an internally rotated or adducted arm, with the arm held in INTERNAL ROTATION and ADDUCTION and loss of the normal rounded anterior shoulder contour? The CARDINAL SIGN is marked limitation of EXTERNAL ROTATION \u2014 the patient cannot turn the palm outward. Suspect it from the mechanism plus a fixed, internally rotated, painful, functionless shoulder. Requires a true lateral or axillary view to confirm and timely reduction; a missed posterior dislocation becomes locked and chronic.",
       "question": "Easily missed \u2014 often invisible on the AP X-ray. After a seizure, electric shock, or a fall on an internally rotated arm: arm locked in INTERNAL ROTATION/adduction with marked loss of EXTERNAL ROTATION (cardinal sign). Needs an axillary/true-lateral view and timely reduction.",
       "source": "Brukner & Khan Ch.17 (posterior dislocation of the glenohumeral joint)"
       "source": "Brukner & Khan Ch.17 (posterior dislocation of the glenohumeral joint)"
     },
     },
Line 1,012: Line 1,033:
       "id": "rf-u2",
       "id": "rf-u2",
       "label": "Proximal humerus (humeral neck) fracture",
       "label": "Proximal humerus (humeral neck) fracture",
       "question": "After a fall onto the outstretched hand or direct violence \u2014 and in osteoporotic older adults or adolescents \u2014 with anterior shoulder and upper-arm pain, marked tenderness, swelling, and inability to use the arm? Fractures with more than two fragments, displacement greater than 1 cm, significant angulation, or any associated glenohumeral dislocation need prompt orthopaedic assessment and possible fixation; minimally displaced or impacted fractures are managed conservatively. Assess axillary nerve sensation (lateral shoulder 'regimental badge' area) and distal neurovascular status, as anterior dislocation/fracture can injure the axillary nerve.",
       "question": "After a fall on the outstretched hand or a direct blow (esp. older/osteoporotic): shoulder pain, tenderness, swelling, can't use the arm. >2 fragments, displacement >1 cm, angulation, or associated dislocation \u2192 orthopaedic referral. Check axillary-nerve sensation (lateral shoulder) and distal neurovascular status.",
       "source": "Brukner & Khan Ch.17 (fracture of the neck of the humerus; axillary nerve injury)"
       "source": "Brukner & Khan Ch.17 (fracture of the neck of the humerus; axillary nerve injury)"
     },
     },
Line 1,018: Line 1,039:
       "id": "rf-u3",
       "id": "rf-u3",
       "label": "Acute massive rotator cuff tear",
       "label": "Acute massive rotator cuff tear",
       "question": "Sudden loss of active shoulder elevation or external rotation after a forceful injury (or acute-on-chronic deterioration in an older adult), with night pain and weakness on supraspinatus and external-rotation testing while PASSIVE range is preserved (pseudoparalysis)? Positive impingement signs and inability to sleep on the shoulder are common. A full-thickness or massive tear \u2014 particularly an acute traumatic tear in a younger patient \u2014 warrants timely imaging (ultrasound or MRI) and surgical referral, as early repair improves outcome. Anterior deltoid and supraspinatus trigger-point patterns may coexist but do NOT produce true power loss with preserved passive motion.",
       "question": "Sudden loss of active elevation or external rotation after trauma (or acute-on-chronic in older adults), with night pain and weakness but PRESERVED passive range (pseudoparalysis) and positive impingement signs. Timely US/MRI and surgical referral \u2014 early repair improves outcome. TrPs don't cause true power loss with preserved passive motion.",
       "source": "Brukner & Khan Ch.17 (rotator cuff strains/tears); JOSPT 2009 LHBT review (associated cuff disease)"
       "source": "Brukner & Khan Ch.17 (rotator cuff strains/tears); JOSPT 2009 LHBT review (associated cuff disease)"
     },
     },
Line 1,024: Line 1,045:
       "id": "rf-u4",
       "id": "rf-u4",
       "label": "Long head of biceps (LHB) tendon rupture",
       "label": "Long head of biceps (LHB) tendon rupture",
       "question": "A sudden painful 'pop' or tearing sensation in the front of the upper arm during a lift or eccentric load, followed by a visible 'Popeye' bulge of the muscle belly low in the arm (accentuated by elbow flexion), with ecchymosis and often surprisingly little residual pain and near-preserved strength? Common in older adults and frequently associated with rotator-cuff/subscapularis disease or biceps instability \u2014 so examine the cuff and screen for medial biceps subluxation. Most middle-aged or low-demand patients do well with reassurance and rehabilitation; younger patients, manual laborers, or athletes concerned with supination strength or cosmesis are referred to consider tenodesis or tenotomy. Confirm with ultrasound or MRI if the diagnosis is unclear.",
       "question": "Sudden 'pop' in the front of the arm on a lift, then a 'Popeye' bulge low in the arm (worse on elbow flexion), with bruising, little residual pain, and near-normal strength. Examine the cuff/subscapularis (commonly associated). Older/low-demand: reassurance + rehab; refer younger patients, laborers, or athletes for tenodesis/tenotomy.",
       "source": "Long Head of the Biceps Tendon JOSPT 2009 (Nho et al.); Proximal Biceps Tendinitis and Tendinopathy StatPearls (Varacallo & Mair); Brukner & Khan Ch.17 (rupture of the long head of the biceps)"
       "source": "Long Head of the Biceps Tendon JOSPT 2009 (Nho et al.); Proximal Biceps Tendinitis and Tendinopathy StatPearls (Varacallo & Mair); Brukner & Khan Ch.17 (rupture of the long head of the biceps)"
     },
     },
Line 1,030: Line 1,051:
       "id": "rf-u5",
       "id": "rf-u5",
       "label": "Distal biceps tendon rupture",
       "label": "Distal biceps tendon rupture",
       "question": "A sudden painful tearing at the FRONT OF THE ELBOW (antecubital fossa) during a forceful eccentric flexion load \u2014 classically catching a heavy falling object \u2014 with antecubital pain, swelling and ecchymosis, a palpable tendon defect, and PROXIMAL retraction of the muscle belly (a 'reverse Popeye')? A positive hook test (the examiner cannot hook a finger under the distal biceps tendon in the fossa) supports it, and supination strength is notably weak. Unlike the largely benign LHB rupture, a complete distal biceps avulsion in an active adult is typically referred for EARLY surgical repair (within about 2\u20133 weeks) to restore supination and flexion strength. Distinguish from biceps/brachialis trigger-point pain, which has no defect, no retraction, and preserved strength.",
       "question": "Sudden tearing at the FRONT OF THE ELBOW on a forceful eccentric load (catching a heavy object): antecubital pain, bruising, palpable defect, muscle belly retracts PROXIMALLY (reverse-Popeye), positive hook test, weak supination. Refer for EARLY repair (~2\u20133 weeks). TrP pain has no defect/retraction and normal strength.",
       "source": "Brukner & Khan Ch.18 (distal biceps rupture) [VERIFY against your Ch.18 copy]"
       "source": "Brukner & Khan Ch.18 (distal biceps rupture) [VERIFY against your Ch.18 copy]"
     },
     },
Line 1,036: Line 1,057:
       "id": "rf-u6",
       "id": "rf-u6",
       "label": "Humeral shaft stress fracture / spiral fracture (throwers)",
       "label": "Humeral shaft stress fracture / spiral fracture (throwers)",
       "question": "Activity-related upper-arm pain that builds with throwing or repetitive loading and localises to the mid or lower humeral shaft with focal bony tenderness \u2014 or a sudden closed SPIRAL fracture during a hard throw (often with prodromal pain at the site)? Seen in throwing athletes; the spiral fracture occurs near the junction of the middle and lower thirds along the radial groove and risks RADIAL NERVE injury (test wrist, finger, and thumb extension and dorsal first-web-space sensation). Needs activity cessation and imaging \u2014 a stress fracture may be occult on early plain films; the acute fracture usually heals in a cast or functional brace. Myofascial arm pain is reproduced by muscle palpation and lacks focal bony tenderness.",
       "question": "Throwing-related upper-arm pain that builds with load, with focal bony tenderness at the mid/lower shaft \u2014 or a sudden SPIRAL fracture on a hard throw. Risks RADIAL NERVE injury (test wrist/finger/thumb extension and dorsal first-web sensation). Stop activity and image (a stress fracture may be occult early). Myofascial pain lacks focal bony tenderness.",
       "source": "Brukner & Khan Ch.17 (throwing fracture of the humeral shaft); Ch.18 [VERIFY arm/elbow detail against your Ch.18 copy]"
       "source": "Brukner & Khan Ch.17 (throwing fracture of the humeral shaft); Ch.18 [VERIFY arm/elbow detail against your Ch.18 copy]"
     },
     },
Line 1,042: Line 1,063:
       "id": "rf-u7",
       "id": "rf-u7",
       "label": "Vascular thoracic outlet syndrome / subclavian effort thrombosis (Paget-Schroetter)",
       "label": "Vascular thoracic outlet syndrome / subclavian effort thrombosis (Paget-Schroetter)",
       "question": "ARTERIAL: pallor, coolness, claudication, or a diminished/absent radial pulse when the arm is elevated and abducted-externally rotated, in an overhead athlete or someone with a cervical rib \u2014 arterial compression (often by a complete cervical rib) can thrombose or embolise and is limb-threatening. VENOUS (Paget-Schroetter 'effort' thrombosis): sudden diffuse swelling, bluish discoloration, heaviness or aching, and prominent superficial veins of the WHOLE arm after vigorous or repetitive overhead activity. Subclavius shortening draws the clavicle down toward the costoclavicular space and is this model's vascular-TOS link (with clavicular pectoralis major). Confirm with duplex ultrasound or venography (venous) or arterial studies; venous thrombosis needs prompt anticoagulation +/- thrombolysis and a TOS work-up. NOTE: NEUROGENIC TOS \u2014 the far more common subtype (paraesthesia, the nocturnal arm-hanging pattern, Roos/Wright provocation) \u2014 is NOT an emergency and is covered on [[Differential:ThoracicOutletSyndrome]]; cross-link there rather than duplicating it here.",
       "question": "ARTERIAL: pallor, coolness, claudication, or a lost radial pulse on arm elevation/abduction-ER (cervical rib) \u2014 limb-threatening. VENOUS (Paget-Schroetter): sudden swelling, bluish discoloration, and a heavy WHOLE arm with prominent veins after heavy overhead activity. Duplex/venography; venous needs anticoagulation \u00b1 thrombolysis + TOS work-up. NEUROGENIC TOS (paraesthesia, nocturnal arm-hang) is NOT urgent \u2014 see [[Differential:ThoracicOutletSyndrome]].",
       "source": "Brukner & Khan Ch.17 (thoracic outlet syndrome; axillary vein 'effort' thrombosis / Paget-von Schrotter syndrome)"
       "source": "Brukner & Khan Ch.17 (thoracic outlet syndrome; axillary vein 'effort' thrombosis / Paget-von Schrotter syndrome)"
     }
     }

Latest revision as of 21:45, 12 June 2026

{ 

 "model": "bayesian_lr_scoring",
 "version": "1.0",
 "region_label": "Front of Arm Pain",
 "description": "Probabilistic scoring model for front-of-arm pain using Bayesian likelihood ratio updating with Thurstonian pairwise tiebreakers. Muscles drawn from T&S Vol.1 Ch.18 (Overview: Upper Back, Shoulder, and Arm) and individual chapters. Bold muscles carry higher priors (0.12); regular-weight muscles carry lower priors (0.08). Triceps TrP5 = medial head, referring to medial epicondyle and medial forearm.",
 "thresholds": {
   "early_exit_posterior": 0.55,
   "early_exit_gap": 0.18,
   "pairwise_trigger": 0.22
 },
 "muscles": {
   "biceps": {
     "label": "Biceps Brachii",
     "prior": 0.12,
     "page": "Muscle:Biceps_Brachii",
     "key_trp_note": "Infraspinatus TrPs are the most important key TrP source driving satellite biceps TrPs. Inactivating infraspinatus is essential for sustained biceps relief and may alone resolve the biceps TrPs. With prolonged biceps TrP activity, expect secondary TrPs in brachialis, supinator, and triceps (in that sequence).",
     "subtitle": "Superficial anterior shoulder aching; can lie on affected side; can reach behind waist"
   },
   "brachialis": {
     "label": "Brachialis",
     "prior": 0.08,
     "page": "Muscle:Brachialis",
     "key_trp_note": "Brachialis TrPs are almost always co-active with biceps brachii TrPs. In the tennis elbow pattern, the supinator is the primary TrP; brachialis develops secondarily. The almond-shaped lateral border TrP specifically compresses the sensory radial nerve branch \u2014 causing dorsal thumb dysesthesia alongside the referred aching.",
     "subtitle": "Thumb base and dorsal web of thumb; thumb hurts not elbow; passive elbow extension worsens pain"
   },
   "scalene": {
     "label": "Scalene",
     "prior": 0.12,
     "page": "Muscle:Scalene",
     "key_trp_note": "Scalene TrPs drive satellite TrPs in biceps brachii, pectoralis major/minor, serratus posterior superior, and upper trapezius. Treat scalenes before their satellites. SCM should be treated concurrently.",
     "subtitle": "Anterior chest and arm symptoms; nocturnal arm aching; must hang arm over bed for relief"
   },
   "scalenus_minimus": {
     "label": "Scalenus Minimus",
     "prior": 0.12,
     "page": "Muscle:Scalene",
     "key_trp_note": "Scalenus minimus (when present) is anatomically positioned to compress the lower trunk of the brachial plexus against the first rib. Its TrPs produce a distinct radial-hand pattern extending to the thumb and index finger. Treat as part of the scalene group in the same session.",
     "subtitle": "Posterior arm to radial hand/thumb; lower brachial plexus compression pattern"
   },
   "subclavius": {
     "label": "Subclavius",
     "prior": 0.12,
     "page": "Muscle:Pectoralis_Major",
     "key_trp_note": "Subclavius TrPs almost always coexist with clavicular pectoralis major TrPs. Subclavius shortening draws the clavicle down toward the subclavian neurovascular structures \u2014 vascular thoracic outlet syndrome. Treat clavicular pectoralis major first.",
     "subtitle": "Radial forearm and hand SKIPPING the elbow and wrist; thumb, index, and middle fingers"
   },
   "triceps_trp5": {
     "label": "Triceps \u2014 Medial Head (TrP5)",
     "prior": 0.12,
     "page": "Muscle:Triceps_Brachii",
     "key_trp_note": "Triceps TrP5 (medial head) refers to the medial epicondyle and medial forearm \u2014 the front-of-arm pattern that distinguishes it from TrP1 (posterior arm, long head) and TrP3 (lateral head, radial nerve zone). Scalene TrPs drive triceps long head satellite TrPs; the medial head may be activated independently by direct overload or antagonist cramping from biceps/brachialis treatment.",
     "subtitle": "Medial epicondyle and medial forearm pain from anterior arm; antagonist cramping after biceps treatment"
   },
   "infraspinatus": {
     "label": "Infraspinatus",
     "prior": 0.08,
     "page": "Muscle:Infraspinatus",
     "key_trp_note": "Infraspinatus is the key TrP source driving satellite biceps brachii TrPs. Inactivating infraspinatus first is essential \u2014 biceps TrPs may resolve without direct treatment once infraspinatus is addressed. Primary infraspinatus presentation is deep anterior joint pain; when it appears in a front-of-arm algorithm it usually reflects the satellite biceps being masked by the primary source.",
     "subtitle": "Deep inside anterior shoulder joint; cannot sleep either side; cannot reach behind back"
   },
   "supraspinatus": {
     "label": "Supraspinatus",
     "prior": 0.08,
     "page": "Muscle:Supraspinatus",
     "key_trp_note": "Supraspinatus TrPs refer to the mid-deltoid and lateral upper arm. Infraspinatus TrPs often drive supraspinatus satellites. With prolonged biceps TrP activity, supraspinatus eventually develops secondary TrPs. Inactivating supraspinatus usually resolves middle deltoid satellite TrPs without direct treatment.",
     "subtitle": "Lateral shoulder to lateral upper arm; lateral epicondyle referral; painful arc 60\u2013120\u00b0"
   },
   "deltoid_anterior": {
     "label": "Anterior Deltoid",
     "prior": 0.08,
     "page": "Muscle:Deltoid",
     "key_trp_note": "Anterior deltoid TrPs are almost always satellites of infraspinatus, supraspinatus, or pectoralis major key TrPs \u2014 the anterior deltoid lies in the pain reference zone of all three. Treat the key TrP source first; anterior deltoid TrPs usually resolve without direct treatment.",
     "subtitle": "Local anterior shoulder surface only; no arm or hand referral; history of direct impact or injection"
   },
   "sternalis": {
     "label": "Sternalis",
     "prior": 0.08,
     "page": "Muscle:Sternalis",
     "key_trp_note": "Sternalis TrPs are almost always co-active with pectoralis major TrPs. SCM sternal division (lower end) may refer pain downward over the sternum and activate sternalis as a satellite. Present in only ~4\u20135% of the population. Treat pectoralis major and SCM before or alongside sternalis.",
     "subtitle": "Deep substernal ache; movement-independent; cardiac mimic; may extend to front of shoulder and upper arm"
   }
 },
 "questions": [
   {
     "id": "q_dominant_pain_zone",
     "text": "Where is the front-of-arm pain most concentrated?",
     "sublabel": "Choose the single best description of the dominant pain zone",
     "type": "choice",
     "answers": [
       {
         "id": "anterior_shoulder_surface",
         "label": "Surface of the ANTERIOR SHOULDER \u2014 front of the shoulder bulge; superficial aching",
         "sublabel": "Superficial aching over the front of the shoulder and deltoid region; NOT deep inside the joint",
         "lr": {
           "biceps": 8.0,
           "deltoid_anterior": 5.0,
           "supraspinatus": 2.0,
           "scalene": 1.5,
           "infraspinatus": 0.3,
           "brachialis": 0.5,
           "subclavius": 1.0,
           "scalenus_minimus": 0.8,
           "triceps_trp5": 0.5,
           "sternalis": 0.5
         }
       },
       {
         "id": "deep_inside_joint",
         "label": "DEEP INSIDE the front of the shoulder joint \u2014 patient places hand over the anterior shoulder",
         "sublabel": "The pain is felt inside the joint itself, not on the surface",
         "lr": {
           "infraspinatus": 10.0,
           "biceps": 1.0,
           "deltoid_anterior": 0.3,
           "supraspinatus": 1.0,
           "scalene": 0.7,
           "brachialis": 0.3,
           "subclavius": 0.4,
           "scalenus_minimus": 0.4,
           "triceps_trp5": 0.3,
           "sternalis": 0.3
         }
       },
       {
         "id": "biceps_belly_antecubital",
         "label": "BICEPS MUSCLE BELLY or ANTECUBITAL SPACE \u2014 front of the upper arm or elbow crease",
         "sublabel": "The arm itself hurts, not just the shoulder; the antecubital fossa may also ache",
         "lr": {
           "biceps": 5.0,
           "brachialis": 6.0,
           "scalene": 1.5,
           "triceps_trp5": 2.0,
           "infraspinatus": 0.5,
           "supraspinatus": 0.8,
           "deltoid_anterior": 0.4,
           "subclavius": 0.8,
           "scalenus_minimus": 0.8,
           "sternalis": 0.4
         }
       },
       {
         "id": "substernal_chest",
         "label": "SUBSTERNAL or anterior chest \u2014 behind the breastbone or across the front of the chest",
         "sublabel": "The dominant pain is in the chest, not in the arm itself",
         "lr": {
           "sternalis": 12.0,
           "scalene": 2.0,
           "subclavius": 1.5,
           "scalenus_minimus": 1.0,
           "biceps": 0.3,
           "brachialis": 0.2,
           "infraspinatus": 0.2,
           "supraspinatus": 0.2,
           "deltoid_anterior": 0.3,
           "triceps_trp5": 0.3
         }
       }
     ]
   },
   {
     "id": "q_thumb_pain",
     "text": "Is the thumb affected \u2014 specifically pain or soreness at the BASE of the thumb or dorsal web space of the thumb?",
     "sublabel": "The thumb hurts at its base (carpometacarpal joint area) or on the back of the thumb web; this is the dominant or a prominent complaint",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes \u2014 thumb base or dorsal thumb web is painful or sore",
         "lr": {
           "brachialis": 12.0,
           "subclavius": 3.0,
           "scalenus_minimus": 3.0,
           "scalene": 1.5,
           "biceps": 0.4,
           "infraspinatus": 0.4,
           "supraspinatus": 0.3,
           "deltoid_anterior": 0.2,
           "triceps_trp5": 0.3,
           "sternalis": 0.2
         }
       },
       {
         "id": "no",
         "label": "No \u2014 thumb is not specifically affected",
         "lr": {
           "brachialis": 0.15,
           "subclavius": 0.7,
           "scalenus_minimus": 0.7,
           "scalene": 0.9,
           "biceps": 1.2,
           "infraspinatus": 1.2,
           "supraspinatus": 1.2,
           "deltoid_anterior": 1.3,
           "triceps_trp5": 1.2,
           "sternalis": 1.2
         }
       }
     ]
   },
   {
     "id": "q_thumb_vs_elbow",
     "text": "Regarding pain when moving the arm or thumb: which hurts more?",
     "sublabel": "A key brachialis dissociation test \u2014 the thumb hurts with use; the elbow does not",
     "type": "choice",
     "condition": {
       "q_thumb_pain": "yes"
     },
     "answers": [
       {
         "id": "thumb_hurts_elbow_ok",
         "label": "Active thumb movement HURTS; active elbow movement does NOT hurt",
         "sublabel": "Using the thumb causes pain; bending or straightening the elbow does not",
         "lr": {
           "brachialis": 14.0,
           "subclavius": 1.5,
           "scalenus_minimus": 1.5,
           "scalene": 0.8,
           "biceps": 0.3,
           "infraspinatus": 0.3,
           "supraspinatus": 0.3,
           "deltoid_anterior": 0.3,
           "triceps_trp5": 0.3,
           "sternalis": 0.2
         }
       },
       {
         "id": "elbow_also_hurts",
         "label": "Both the thumb AND the elbow hurt with movement",
         "sublabel": "Elbow movement is also painful, not just the thumb",
         "lr": {
           "brachialis": 2.0,
           "subclavius": 2.0,
           "scalenus_minimus": 2.0,
           "scalene": 1.5,
           "biceps": 1.5,
           "infraspinatus": 0.5,
           "supraspinatus": 0.5,
           "deltoid_anterior": 0.4,
           "triceps_trp5": 1.5,
           "sternalis": 0.3
         }
       }
     ]
   },
   {
     "id": "q_sleep",
     "text": "How does the arm pain affect sleep?",
     "sublabel": "Which sleeping position is tolerated?",
     "type": "choice",
     "answers": [
       {
         "id": "neither_side",
         "label": "Cannot sleep on EITHER side \u2014 may sleep upright or propped in a chair",
         "sublabel": "Even the unaffected side causes pain; every lying position wakes the patient",
         "lr": {
           "infraspinatus": 10.0,
           "scalene": 2.0,
           "biceps": 1.0,
           "brachialis": 0.5,
           "supraspinatus": 0.5,
           "deltoid_anterior": 0.3,
           "subclavius": 0.4,
           "scalenus_minimus": 0.4,
           "triceps_trp5": 0.4,
           "sternalis": 0.5
         }
       },
       {
         "id": "not_affected_side",
         "label": "Cannot sleep on the AFFECTED side only",
         "sublabel": "Lying on the painful arm wakes the patient; other positions are tolerated",
         "lr": {
           "biceps": 5.0,
           "deltoid_anterior": 3.0,
           "supraspinatus": 2.5,
           "brachialis": 2.0,
           "triceps_trp5": 2.0,
           "scalene": 1.0,
           "subclavius": 1.0,
           "scalenus_minimus": 0.8,
           "infraspinatus": 0.4,
           "sternalis": 1.0
         }
       },
       {
         "id": "sleep_ok",
         "label": "Sleep is largely unaffected or only mildly disturbed",
         "sublabel": "The patient finds a comfortable position without significant waking",
         "lr": {
           "sternalis": 3.0,
           "subclavius": 2.0,
           "scalenus_minimus": 1.5,
           "scalene": 1.5,
           "deltoid_anterior": 1.5,
           "supraspinatus": 1.0,
           "brachialis": 1.0,
           "biceps": 0.5,
           "infraspinatus": 0.2,
           "triceps_trp5": 1.2
         }
       }
     ]
   },
   {
     "id": "q_behind_back",
     "text": "Can the patient reach comfortably behind the back?",
     "sublabel": "Test: reaching the arm behind the back to the hip pocket or brassiere hooks",
     "type": "binary",
     "answers": [
       {
         "id": "restricted",
         "label": "Painful or restricted \u2014 cannot reach behind the back fully",
         "lr": {
           "infraspinatus": 8.0,
           "biceps": 3.0,
           "supraspinatus": 2.0,
           "brachialis": 1.5,
           "scalene": 1.0,
           "deltoid_anterior": 0.6,
           "subclavius": 0.5,
           "scalenus_minimus": 0.4,
           "triceps_trp5": 0.5,
           "sternalis": 0.4
         }
       },
       {
         "id": "normal",
         "label": "Full behind-back reach \u2014 no restriction",
         "lr": {
           "infraspinatus": 0.2,
           "biceps": 0.5,
           "supraspinatus": 0.7,
           "brachialis": 0.9,
           "scalene": 1.0,
           "deltoid_anterior": 1.4,
           "subclavius": 1.4,
           "scalenus_minimus": 1.4,
           "triceps_trp5": 1.3,
           "sternalis": 1.4
         }
       }
     ]
   },
   {
     "id": "q_elbow_extension_test",
     "text": "Does PASSIVELY straightening (extending) the elbow increase pain in the arm, antecubital space, or thumb?",
     "sublabel": "With the arm relaxed, the examiner gently straightens the elbow fully \u2014 does this increase pain?",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes \u2014 passively extending the elbow worsens pain",
         "lr": {
           "brachialis": 10.0,
           "biceps": 4.0,
           "triceps_trp5": 1.5,
           "scalene": 0.8,
           "infraspinatus": 0.5,
           "supraspinatus": 0.5,
           "deltoid_anterior": 0.4,
           "subclavius": 0.5,
           "scalenus_minimus": 0.5,
           "sternalis": 0.3
         }
       },
       {
         "id": "no",
         "label": "No \u2014 elbow extension does not worsen pain",
         "lr": {
           "brachialis": 0.2,
           "biceps": 0.6,
           "triceps_trp5": 1.0,
           "scalene": 1.1,
           "infraspinatus": 1.2,
           "supraspinatus": 1.2,
           "deltoid_anterior": 1.3,
           "subclavius": 1.2,
           "scalenus_minimus": 1.2,
           "sternalis": 1.2
         }
       }
     ]
   },
   {
     "id": "q_supination_vs_pronation",
     "text": "Is arm pain or weakness worse when the forearm is SUPINATED (palm up) compared to PRONATED (palm down) during elbow flexion?",
     "sublabel": "Test: flex the elbow with palm facing up, then repeat with palm facing down \u2014 which position is more painful or weak?",
     "type": "choice",
     "answers": [
       {
         "id": "supination_worse",
         "label": "Supination (palm up) is more painful or weak than pronation (palm down)",
         "sublabel": "Lifting with palm up hurts more than lifting with palm down",
         "lr": {
           "biceps": 8.0,
           "scalene": 1.5,
           "infraspinatus": 1.0,
           "brachialis": 0.4,
           "supraspinatus": 0.8,
           "deltoid_anterior": 0.7,
           "subclavius": 0.8,
           "scalenus_minimus": 0.8,
           "triceps_trp5": 0.5,
           "sternalis": 0.5
         }
       },
       {
         "id": "equal_both",
         "label": "Both positions are equally painful or weak",
         "sublabel": "No difference between palm up and palm down during elbow flexion",
         "lr": {
           "brachialis": 6.0,
           "triceps_trp5": 2.0,
           "scalene": 1.5,
           "scalenus_minimus": 1.5,
           "subclavius": 1.5,
           "sternalis": 1.5,
           "infraspinatus": 1.0,
           "supraspinatus": 1.0,
           "biceps": 0.4,
           "deltoid_anterior": 1.0
         }
       },
       {
         "id": "no_difference_painless",
         "label": "No pain with either position \u2014 elbow flexion is not a trigger",
         "sublabel": "Bending the elbow does not provoke the arm pain",
         "lr": {
           "infraspinatus": 2.0,
           "deltoid_anterior": 2.0,
           "sternalis": 2.0,
           "subclavius": 1.5,
           "scalenus_minimus": 1.5,
           "scalene": 1.5,
           "supraspinatus": 1.5,
           "biceps": 0.4,
           "brachialis": 0.3,
           "triceps_trp5": 1.0
         }
       }
     ]
   },
   {
     "id": "q_arm_referral",
     "text": "Does the arm pain extend to the forearm or hand?",
     "sublabel": "Choose the best description of the distal referral",
     "type": "choice",
     "answers": [
       {
         "id": "radial_skip",
         "label": "Radial forearm and/or thumb/index/middle fingers \u2014 SKIPPING the elbow and wrist",
         "sublabel": "The radial side of the forearm and/or the thumb, index, or middle finger hurt; the elbow joint area is pain-free",
         "lr": {
           "subclavius": 10.0,
           "scalenus_minimus": 6.0,
           "brachialis": 3.0,
           "scalene": 2.0,
           "biceps": 0.5,
           "infraspinatus": 0.8,
           "supraspinatus": 0.5,
           "deltoid_anterior": 0.2,
           "triceps_trp5": 0.4,
           "sternalis": 0.3
         }
       },
       {
         "id": "medial_epicondyle",
         "label": "Medial epicondyle (inner elbow) and/or medial forearm",
         "sublabel": "The inner bump of the elbow and/or the medial forearm is part of the pain",
         "lr": {
           "triceps_trp5": 9.0,
           "scalene": 2.0,
           "brachialis": 1.5,
           "biceps": 1.0,
           "scalenus_minimus": 1.0,
           "infraspinatus": 0.5,
           "supraspinatus": 0.4,
           "subclavius": 0.4,
           "deltoid_anterior": 0.3,
           "sternalis": 0.3
         }
       },
       {
         "id": "ulnar_forearm_hand",
         "label": "Ulnar forearm and/or ring and little fingers",
         "sublabel": "The inner forearm and/or the two ulnar digits hurt",
         "lr": {
           "scalene": 4.0,
           "scalenus_minimus": 2.0,
           "sternalis": 2.0,
           "brachialis": 1.0,
           "biceps": 0.5,
           "triceps_trp5": 1.5,
           "subclavius": 0.5,
           "infraspinatus": 0.5,
           "supraspinatus": 0.4,
           "deltoid_anterior": 0.3
         }
       },
       {
         "id": "suprascapular_spillover",
         "label": "Pain skips upward to the suprascapular region \u2014 above the scapular spine",
         "sublabel": "The area above the shoulder blade also aches, almost as if the pain jumps over the shoulder",
         "lr": {
           "biceps": 7.0,
           "scalene": 2.0,
           "infraspinatus": 1.5,
           "supraspinatus": 1.5,
           "scalenus_minimus": 1.0,
           "brachialis": 0.5,
           "deltoid_anterior": 0.4,
           "subclavius": 0.5,
           "triceps_trp5": 0.4,
           "sternalis": 0.4
         }
       },
       {
         "id": "lateral_arm_epicondyle",
         "label": "Lateral upper arm or lateral epicondyle \u2014 outer elbow region",
         "sublabel": "The outer side of the upper arm or the outer elbow bump is included in the pain",
         "lr": {
           "supraspinatus": 7.0,
           "biceps": 1.0,
           "scalene": 1.5,
           "infraspinatus": 1.5,
           "brachialis": 0.5,
           "deltoid_anterior": 0.8,
           "subclavius": 0.5,
           "scalenus_minimus": 0.5,
           "triceps_trp5": 0.5,
           "sternalis": 0.3
         }
       },
       {
         "id": "no_distal_referral",
         "label": "No forearm or hand referral \u2014 pain stays in the shoulder and upper arm",
         "sublabel": "Pain does not travel below the elbow",
         "lr": {
           "deltoid_anterior": 3.0,
           "sternalis": 3.0,
           "infraspinatus": 1.5,
           "biceps": 1.0,
           "supraspinatus": 1.0,
           "brachialis": 0.5,
           "scalene": 0.5,
           "subclavius": 0.4,
           "scalenus_minimus": 0.4,
           "triceps_trp5": 0.5
         }
       }
     ]
   },
   {
     "id": "q_nocturnal_arm",
     "text": "Is the patient woken at night by arm aching or numbness \u2014 requiring the arm to hang over the side of the bed or be shaken for relief?",
     "sublabel": "Nocturnal arm symptoms specifically relieved by hanging the arm over the bed edge",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes \u2014 woken at night; arm must hang over bed side for relief",
         "lr": {
           "scalene": 9.0,
           "scalenus_minimus": 5.0,
           "subclavius": 2.0,
           "brachialis": 0.5,
           "biceps": 0.5,
           "infraspinatus": 0.5,
           "supraspinatus": 0.4,
           "deltoid_anterior": 0.3,
           "triceps_trp5": 0.4,
           "sternalis": 0.3
         }
       },
       {
         "id": "no",
         "label": "No \u2014 no nocturnal arm hanging symptom",
         "lr": {
           "scalene": 0.25,
           "scalenus_minimus": 0.35,
           "subclavius": 0.8,
           "brachialis": 1.1,
           "biceps": 1.1,
           "infraspinatus": 1.1,
           "supraspinatus": 1.1,
           "deltoid_anterior": 1.2,
           "triceps_trp5": 1.1,
           "sternalis": 1.1
         }
       }
     ]
   },
   {
     "id": "q_movement_independence",
     "text": "Is the arm or chest pain MOVEMENT-INDEPENDENT \u2014 present at rest and NOT worsened by any specific shoulder or arm movement?",
     "sublabel": "No position, movement, or activity clearly makes the pain better or worse",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes \u2014 pain present at rest, unchanged by movement",
         "lr": {
           "sternalis": 10.0,
           "scalene": 2.0,
           "scalenus_minimus": 1.5,
           "biceps": 0.5,
           "brachialis": 0.4,
           "infraspinatus": 0.5,
           "supraspinatus": 0.4,
           "deltoid_anterior": 0.5,
           "subclavius": 0.5,
           "triceps_trp5": 0.5
         }
       },
       {
         "id": "no",
         "label": "No \u2014 pain varies with position, activity, or movement",
         "lr": {
           "sternalis": 0.2,
           "scalene": 0.9,
           "scalenus_minimus": 0.9,
           "biceps": 1.2,
           "brachialis": 1.2,
           "infraspinatus": 1.2,
           "supraspinatus": 1.2,
           "deltoid_anterior": 1.2,
           "subclavius": 1.1,
           "triceps_trp5": 1.1
         }
       }
     ]
   },
   {
     "id": "q_painful_arc",
     "text": "Is there a painful arc during shoulder abduction \u2014 pain appearing between 60\u00b0 and 120\u00b0 of raising the arm sideways, then diminishing above that?",
     "sublabel": "Pain appears then disappears as the arm reaches overhead",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes \u2014 painful arc between 60\u00b0 and 120\u00b0 of abduction",
         "lr": {
           "supraspinatus": 8.0,
           "deltoid_anterior": 2.0,
           "biceps": 0.8,
           "infraspinatus": 0.7,
           "brachialis": 0.4,
           "scalene": 0.5,
           "scalenus_minimus": 0.4,
           "subclavius": 0.4,
           "triceps_trp5": 0.4,
           "sternalis": 0.3
         }
       },
       {
         "id": "no",
         "label": "No \u2014 no arc pattern; abduction is uniformly painful or pain-free",
         "lr": {
           "supraspinatus": 0.2,
           "deltoid_anterior": 0.9,
           "biceps": 1.1,
           "infraspinatus": 1.1,
           "brachialis": 1.2,
           "scalene": 1.1,
           "scalenus_minimus": 1.1,
           "subclavius": 1.1,
           "triceps_trp5": 1.2,
           "sternalis": 1.2
         }
       }
     ]
   },
   {
     "id": "q_onset",
     "text": "How did the front-of-arm pain begin?",
     "sublabel": "Choose the onset pattern that best describes this episode",
     "type": "choice",
     "answers": [
       {
         "id": "sustained_flexion_load",
         "label": "Sustained elbow flexion under load \u2014 carrying groceries, using power tools at elbow height, ironing, violin playing",
         "sublabel": "Pain crept in over repeated sessions of forearm flexion activity",
         "lr": {
           "brachialis": 8.0,
           "biceps": 5.0,
           "triceps_trp5": 2.0,
           "scalene": 1.0,
           "infraspinatus": 0.5,
           "supraspinatus": 0.5,
           "deltoid_anterior": 0.5,
           "subclavius": 0.7,
           "scalenus_minimus": 0.7,
           "sternalis": 0.4
         }
       },
       {
         "id": "acute_overstretch",
         "label": "Acute overstretch \u2014 catching a fall, reaching backward suddenly, lifting at arm\u2019s length",
         "sublabel": "A specific sudden event the patient can recall",
         "lr": {
           "biceps": 6.0,
           "infraspinatus": 5.0,
           "brachialis": 2.0,
           "deltoid_anterior": 3.0,
           "supraspinatus": 2.0,
           "scalene": 1.0,
           "subclavius": 0.7,
           "scalenus_minimus": 0.7,
           "triceps_trp5": 1.0,
           "sternalis": 0.5
         }
       },
       {
         "id": "gradual_postural",
         "label": "Gradual onset without clear incident \u2014 prolonged desk work, sustained sitting, poor posture",
         "sublabel": "Pain developed insidiously over weeks without a specific event",
         "lr": {
           "scalene": 4.0,
           "scalenus_minimus": 3.0,
           "subclavius": 3.0,
           "sternalis": 2.5,
           "biceps": 1.5,
           "brachialis": 1.0,
           "infraspinatus": 0.5,
           "supraspinatus": 0.8,
           "deltoid_anterior": 1.0,
           "triceps_trp5": 1.5
         }
       },
       {
         "id": "post_cardiac",
         "label": "During or after a cardiac event \u2014 myocardial infarction or sustained angina",
         "sublabel": "Chest and arm pain began or intensified around the time of a cardiac event",
         "lr": {
           "sternalis": 9.0,
           "scalene": 1.5,
           "scalenus_minimus": 1.0,
           "subclavius": 0.8,
           "biceps": 0.3,
           "brachialis": 0.3,
           "infraspinatus": 0.3,
           "supraspinatus": 0.3,
           "deltoid_anterior": 0.3,
           "triceps_trp5": 0.3
         }
       }
     ]
   }
 ],
 "pairwise": [
   {
     "id": "pw_brachialis_biceps",
     "pair": [
       "brachialis",
       "biceps"
     ],
     "text": "Tiebreaker \u2014 Brachialis vs Biceps Brachii",
     "question": "Does elbow flexion pain differ between palm-up and palm-down positions?",
     "answers": [
       {
         "id": "equal_both_positions",
         "label": "Equally painful or weak in both palm-up and palm-down flexion",
         "lr": {
           "brachialis": 5.0,
           "biceps": 0.25
         }
       },
       {
         "id": "worse_palm_up",
         "label": "Worse with palm-up (supinated) flexion than palm-down",
         "lr": {
           "brachialis": 0.25,
           "biceps": 5.0
         }
       }
     ]
   },
   {
     "id": "pw_scalene_scalenus_minimus",
     "pair": [
       "scalene",
       "scalenus_minimus"
     ],
     "text": "Tiebreaker \u2014 Scalene vs Scalenus Minimus",
     "question": "Which arm symptom pattern dominates?",
     "answers": [
       {
         "id": "nocturnal_ulnar",
         "label": "Nocturnal arm aching (hanging over bed) OR posterior arm and ulnar hand symptoms dominate",
         "lr": {
           "scalene": 4.0,
           "scalenus_minimus": 0.3
         }
       },
       {
         "id": "radial_thumb_plexus",
         "label": "Radial forearm, thumb, or lower brachial plexus compression symptoms dominate",
         "lr": {
           "scalene": 0.3,
           "scalenus_minimus": 4.0
         }
       }
     ]
   },
   {
     "id": "pw_subclavius_scalenus_minimus",
     "pair": [
       "subclavius",
       "scalenus_minimus"
     ],
     "text": "Tiebreaker \u2014 Subclavius vs Scalenus Minimus",
     "question": "Does arm abduction worsen the radial forearm and hand symptoms (Wright position), OR is the nocturnal arm pattern more prominent?",
     "answers": [
       {
         "id": "wright_worsens",
         "label": "Arm raised and rotated outward (Wright position) worsens symptoms",
         "lr": {
           "subclavius": 4.0,
           "scalenus_minimus": 0.3
         }
       },
       {
         "id": "nocturnal_lower_plexus",
         "label": "Nocturnal arm symptoms OR lower plexus compression features dominate \u2014 Wright position not specifically positive",
         "lr": {
           "subclavius": 0.3,
           "scalenus_minimus": 4.0
         }
       }
     ]
   },
   {
     "id": "pw_infraspinatus_biceps",
     "pair": [
       "infraspinatus",
       "biceps"
     ],
     "text": "Tiebreaker \u2014 Infraspinatus vs Biceps Brachii",
     "question": "Is the primary pain DEEP INSIDE the shoulder joint, OR is it a superficial surface ache over the anterior shoulder?",
     "answers": [
       {
         "id": "deep_joint",
         "label": "Deep inside the joint \u2014 the patient covers the anterior joint",
         "lr": {
           "infraspinatus": 5.0,
           "biceps": 0.2
         }
       },
       {
         "id": "surface_ache",
         "label": "Superficial surface ache \u2014 can lie comfortably on the affected side",
         "lr": {
           "infraspinatus": 0.2,
           "biceps": 5.0
         }
       }
     ]
   },
   {
     "id": "pw_supraspinatus_biceps",
     "pair": [
       "supraspinatus",
       "biceps"
     ],
     "text": "Tiebreaker \u2014 Supraspinatus vs Biceps Brachii",
     "question": "Is there a painful arc between 60\u00b0 and 120\u00b0 of shoulder abduction, OR is the arm pain primarily at the anterior shoulder without an arc pattern?",
     "answers": [
       {
         "id": "painful_arc",
         "label": "Painful arc between 60\u00b0 and 120\u00b0 of abduction",
         "lr": {
           "supraspinatus": 5.0,
           "biceps": 0.2
         }
       },
       {
         "id": "anterior_shoulder_no_arc",
         "label": "Anterior shoulder aching without a painful arc pattern",
         "lr": {
           "supraspinatus": 0.2,
           "biceps": 4.0
         }
       }
     ]
   },
   {
     "id": "pw_sternalis_scalene",
     "pair": [
       "sternalis",
       "scalene"
     ],
     "text": "Tiebreaker \u2014 Sternalis vs Scalene",
     "question": "Is the chest pain completely unaffected by any shoulder or arm movement, OR do arm or hand symptoms accompany it?",
     "answers": [
       {
         "id": "movement_independent",
         "label": "Completely movement-independent \u2014 no position or activity changes the pain",
         "lr": {
           "sternalis": 5.0,
           "scalene": 0.3
         }
       },
       {
         "id": "arm_symptoms_present",
         "label": "Arm or hand symptoms accompany the chest pain",
         "lr": {
           "sternalis": 0.3,
           "scalene": 4.0
         }
       }
     ]
   },
   {
     "id": "pw_triceps_trp5_brachialis",
     "pair": [
       "triceps_trp5",
       "brachialis"
     ],
     "text": "Tiebreaker \u2014 Triceps Medial Head vs Brachialis",
     "question": "Is the medial epicondyle the dominant distal referral, OR is the thumb base the dominant distal referral?",
     "answers": [
       {
         "id": "medial_epicondyle_dominant",
         "label": "Medial epicondyle (inner elbow) or medial forearm is the dominant distal referral",
         "lr": {
           "triceps_trp5": 5.0,
           "brachialis": 0.25
         }
       },
       {
         "id": "thumb_base_dominant",
         "label": "Thumb base or dorsal web of the thumb is the dominant distal referral",
         "lr": {
           "triceps_trp5": 0.25,
           "brachialis": 5.0
         }
       }
     ]
   }
 ],
 "treatment_dag": {
   "edges": [
     {
       "from": "infraspinatus",
       "to": "biceps",
       "type": "key_satellite",
       "label": "Infraspinatus is the most important key TrP driving satellite biceps TrPs \u2014 treat infraspinatus first; biceps may resolve without direct treatment"
     },
     {
       "from": "biceps",
       "to": "brachialis",
       "type": "functional_unit",
       "label": "Biceps and brachialis are the primary elbow flexor pair \u2014 examine and treat together in the same session"
     },
     {
       "from": "scalene",
       "to": "biceps",
       "type": "key_satellite",
       "label": "Scalene TrPs drive biceps brachii satellite TrPs"
     },
     {
       "from": "scalene",
       "to": "scalenus_minimus",
       "type": "functional_unit",
       "label": "Scalenus minimus (when present) is part of the scalene group \u2014 treat in the same session"
     },
     {
       "from": "biceps",
       "to": "triceps_trp5",
       "type": "antagonist_risk",
       "label": "\u26a0 Triceps (medial head) may reactively cramp when biceps is released \u2014 spray triceps after biceps release; treat in alternating partial cycles if both are active"
     },
     {
       "from": "infraspinatus",
       "to": "supraspinatus",
       "type": "functional_unit",
       "label": "Infraspinatus-supraspinatus team \u2014 almost always active together; treat in the same session"
     },
     {
       "from": "infraspinatus",
       "to": "deltoid_anterior",
       "type": "key_satellite",
       "label": "Infraspinatus is the most important key TrP driving anterior deltoid satellite TrPs"
     },
     {
       "from": "supraspinatus",
       "to": "deltoid_anterior",
       "type": "key_satellite",
       "label": "Supraspinatus TrPs drive anterior and middle deltoid satellite TrPs"
     },
     {
       "from": "subclavius",
       "to": "scalene",
       "type": "secondary_load",
       "label": "Subclavius shortening draws the clavicle down, increasing load on the scalene group \u2014 treat together"
     }
   ],
   "edge_type_labels": {
     "key_satellite": "Treat first \u2014 key TrP driving satellites",
     "functional_unit": "Treat concurrently in same session",
     "secondary_load": "Treat after primary resolves",
     "antagonist_risk": "\u26a0 Treat in alternating cycles \u2014 reactive activation risk"
   }
 },
 "emergency": [
   {
     "id": "rf-e1",
     "label": "Acute coronary syndrome / cardiac ischaemia",
     "question": "Cardiac emergency \u2014 consider FIRST with any anterior-chest or left-arm pain. Central/left chest pressure or tightness radiating to inner arm, neck, or jaw, with sweating, nausea, breathlessness, or rest/exertional onset; often atypical in women, the elderly, and diabetics. Sternalis TrP mimics cardiac pain and TrP relief does NOT exclude ACS. 12-lead ECG within 10 min + troponins before any myofascial label.",
     "source": "Acute Coronary Syndrome StatPearls (NBK459157); Chest Pain: Evaluation and Exclusion of MI and Angina StatPearls (NBK557672); T&S (sternalis cardiac mimicry)"
   },
   {
     "id": "rf-e2",
     "label": "Acute compartment syndrome of the arm",
     "question": "Surgical limb emergency. Arm pain OUT OF PROPORTION, unrelieved by analgesia, worse on PASSIVE finger/elbow stretch (earliest sign), with a tense, swollen arm \u2014 after fracture, crush, tight cast, bleeding/anticoagulation, or hard exertion. Pulselessness, paraesthesia, and paralysis are LATE. Immediate surgical referral; fasciotomy within ~6 h.",
     "source": "Acute Compartment Syndrome StatPearls; Brukner & Khan Ch.18 [VERIFY against your Ch.18 copy + add exact StatPearls NBK id]"
   },
   {
     "id": "rf-e3",
     "label": "Septic glenohumeral arthritis",
     "question": "Joint emergency \u2014 rapid cartilage destruction. Acute, constant, severe deep shoulder pain with pain on ALL movement (active AND passive), often warm or swollen. Fever may be absent or low-grade (only ~17\u201342% of cases) \u2014 a normal temperature does NOT exclude it. Risk: diabetes, immunosuppression, IV drug use, recent injection, prosthesis, bacteraemia. Urgent WBC/ESR/CRP + joint aspiration; drainage + IV antibiotics.",
     "source": "Evaluation and Management of Septic Arthritis in the ED (PMC6404712); Septic Arthritis of the Glenohumeral Joint (PubMed 9653429); Septic Arthritis evidence-based review (AJR 2021, AJR.20.22773)"
   }
 ],
 "urgent": [
   {
     "id": "rf-u1",
     "label": "Posterior glenohumeral dislocation",
     "question": "Easily missed \u2014 often invisible on the AP X-ray. After a seizure, electric shock, or a fall on an internally rotated arm: arm locked in INTERNAL ROTATION/adduction with marked loss of EXTERNAL ROTATION (cardinal sign). Needs an axillary/true-lateral view and timely reduction.",
     "source": "Brukner & Khan Ch.17 (posterior dislocation of the glenohumeral joint)"
   },
   {
     "id": "rf-u2",
     "label": "Proximal humerus (humeral neck) fracture",
     "question": "After a fall on the outstretched hand or a direct blow (esp. older/osteoporotic): shoulder pain, tenderness, swelling, can't use the arm. >2 fragments, displacement >1 cm, angulation, or associated dislocation \u2192 orthopaedic referral. Check axillary-nerve sensation (lateral shoulder) and distal neurovascular status.",
     "source": "Brukner & Khan Ch.17 (fracture of the neck of the humerus; axillary nerve injury)"
   },
   {
     "id": "rf-u3",
     "label": "Acute massive rotator cuff tear",
     "question": "Sudden loss of active elevation or external rotation after trauma (or acute-on-chronic in older adults), with night pain and weakness but PRESERVED passive range (pseudoparalysis) and positive impingement signs. Timely US/MRI and surgical referral \u2014 early repair improves outcome. TrPs don't cause true power loss with preserved passive motion.",
     "source": "Brukner & Khan Ch.17 (rotator cuff strains/tears); JOSPT 2009 LHBT review (associated cuff disease)"
   },
   {
     "id": "rf-u4",
     "label": "Long head of biceps (LHB) tendon rupture",
     "question": "Sudden 'pop' in the front of the arm on a lift, then a 'Popeye' bulge low in the arm (worse on elbow flexion), with bruising, little residual pain, and near-normal strength. Examine the cuff/subscapularis (commonly associated). Older/low-demand: reassurance + rehab; refer younger patients, laborers, or athletes for tenodesis/tenotomy.",
     "source": "Long Head of the Biceps Tendon JOSPT 2009 (Nho et al.); Proximal Biceps Tendinitis and Tendinopathy StatPearls (Varacallo & Mair); Brukner & Khan Ch.17 (rupture of the long head of the biceps)"
   },
   {
     "id": "rf-u5",
     "label": "Distal biceps tendon rupture",
     "question": "Sudden tearing at the FRONT OF THE ELBOW on a forceful eccentric load (catching a heavy object): antecubital pain, bruising, palpable defect, muscle belly retracts PROXIMALLY (reverse-Popeye), positive hook test, weak supination. Refer for EARLY repair (~2\u20133 weeks). TrP pain has no defect/retraction and normal strength.",
     "source": "Brukner & Khan Ch.18 (distal biceps rupture) [VERIFY against your Ch.18 copy]"
   },
   {
     "id": "rf-u6",
     "label": "Humeral shaft stress fracture / spiral fracture (throwers)",
     "question": "Throwing-related upper-arm pain that builds with load, with focal bony tenderness at the mid/lower shaft \u2014 or a sudden SPIRAL fracture on a hard throw. Risks RADIAL NERVE injury (test wrist/finger/thumb extension and dorsal first-web sensation). Stop activity and image (a stress fracture may be occult early). Myofascial pain lacks focal bony tenderness.",
     "source": "Brukner & Khan Ch.17 (throwing fracture of the humeral shaft); Ch.18 [VERIFY arm/elbow detail against your Ch.18 copy]"
   },
   {
     "id": "rf-u7",
     "label": "Vascular thoracic outlet syndrome / subclavian effort thrombosis (Paget-Schroetter)",
     "question": "ARTERIAL: pallor, coolness, claudication, or a lost radial pulse on arm elevation/abduction-ER (cervical rib) \u2014 limb-threatening. VENOUS (Paget-Schroetter): sudden swelling, bluish discoloration, and a heavy WHOLE arm with prominent veins after heavy overhead activity. Duplex/venography; venous needs anticoagulation \u00b1 thrombolysis + TOS work-up. NEUROGENIC TOS (paraesthesia, nocturnal arm-hang) is NOT urgent \u2014 see Differential:ThoracicOutletSyndrome.",
     "source": "Brukner & Khan Ch.17 (thoracic outlet syndrome; axillary vein 'effort' thrombosis / Paget-von Schrotter syndrome)"
   }
 ],
 "broad_differential": [
   {
     "id": "bd-1",
     "condition": "Subacromial impingement / rotator cuff tendinopathy",
     "confidence": "common",
     "mimics": "Anterior and lateral shoulder pain with overhead activity and a painful arc \u2014 overlaps the supraspinatus, anterior deltoid, and biceps anterior-shoulder patterns",
     "distinguishing_feature": "Pain on overhead activity with a painful arc of abduction (roughly 70\u2013120\u00b0), positive Neer and Hawkins-Kennedy impingement signs, and pain on resisted supraspinatus testing ('empty can'). Strength that IMPROVES with scapular retraction points to scapular dyskinesis driving the cuff rather than a true tear. Impingement is a clinical SIGN with several underlying causes (subacromial spur, cuff disease, instability, GIRD, scapular dyskinesis), not a stand-alone diagnosis. Trigger-point referral from supraspinatus/infraspinatus/deltoid is reproduced by muscle palpation and lacks the structural impingement signs.",
     "action": "Neer/Hawkins-Kennedy, painful-arc and empty-can testing, and the scapular assistance test; assess scapular control and posterior-capsule tightness. Relative rest, activity/technique modification, rotator-cuff and periscapular strengthening; consider subacromial corticosteroid injection or imaging (US/MRI) if refractory or a tear is suspected. Treat coexisting cuff and deltoid trigger points.",
     "source": "Brukner & Khan Ch.17 (impingement; rotator cuff tendinopathy)"
   },
   {
     "id": "bd-2",
     "condition": "Long head of biceps tendinopathy / bicipital groove pathology",
     "confidence": "common",
     "mimics": "Anterior shoulder pain localised to the bicipital groove, radiating down the front of the arm \u2014 the structural counterpart of the biceps myofascial pattern",
     "distinguishing_feature": "Point tenderness over the bicipital groove that rotates laterally and medially with arm rotation (distinguishing it from fixed superficial tenderness), with pain on resisted forward flexion (Speed's) and resisted supination (Yergason's). Usually SECONDARY to impingement, cuff disease, or instability rather than isolated. A positive O'Brien (active compression) test raises a SLAP/biceps-anchor lesion. Biceps brachii trigger-point pain is a surface ache reproduced by belly palpation, without groove-specific tenderness or positive provocative tendon tests.",
     "action": "Palpate the groove with rotation; Speed's, Yergason's, and O'Brien tests; screen the cuff and for biceps instability (clunk on abduction-external rotation). Relative rest, NSAIDs, rehabilitation focused on dynamic stability; intra-articular or sheath injection and surgical options (tenodesis/tenotomy) for refractory or structural cases. No treatment reliably benefits isolated biceps fraying \u2014 address the primary driver.",
     "source": "Long Head of the Biceps Tendon JOSPT 2009; Proximal Biceps Tendinitis StatPearls (Varacallo & Mair); Brukner & Khan Ch.17"
   },
   {
     "id": "bd-3",
     "condition": "SLAP lesion / glenohumeral instability",
     "confidence": "uncommon",
     "mimics": "Deep anterior shoulder pain with catching, popping, or a 'dead arm', often in overhead athletes \u2014 overlaps the biceps (anchor) and deep-joint presentations",
     "distinguishing_feature": "Poorly localised deep shoulder pain aggravated by overhead and behind-the-back motion, with popping/catching and sometimes episodes of subluxation or 'dead arm' (transient numbness/weakness). Apprehension in abduction-external rotation relieved by posterior relocation indicates anterior instability; positive O'Brien, crank, or anterior-slide tests suggest a superior labral (SLAP) lesion, which involves the biceps anchor. Generalized ligamentous laxity (sulcus sign) supports multidirectional instability. Trigger-point pain has no apprehension, instability, or labral provocation signs.",
     "action": "Apprehension-augmentation-relocation, load-and-shift, sulcus sign, and SLAP tests (O'Brien, crank, anterior slide) used in combination; MR arthrography for labral detail. Rehabilitation emphasising rotator-cuff and scapular stabilisers and avoidance of provocative positions; arthroscopic stabilisation/labral repair for unstable lesions or failed conservative care.",
     "source": "Brukner & Khan Ch.17 (glenoid labral injuries; shoulder instability)"
   },
   {
     "id": "bd-4",
     "condition": "Acromioclavicular (AC) joint pathology",
     "confidence": "common",
     "mimics": "Well-localised anterosuperior shoulder pain \u2014 can be mistaken for anterior deltoid or supraspinatus referral over the front of the shoulder",
     "distinguishing_feature": "Pain localised precisely to the AC joint at the top of the shoulder, often after a fall onto the point of the shoulder (sprain/separation) or from chronic overuse/osteolysis (weightlifters doing bench press). Reproduced by AC joint compression (Paxinos test) and by cross-body (horizontal) adduction, with possible palpable step deformity in higher-grade separations. Anterior deltoid trigger-point pain sits over the deltoid bulge, not the AC joint, and is not provoked by cross-arm adduction.",
     "action": "Localise tenderness to the AC joint; Paxinos and cross-arm adduction tests; X-ray for separation grade or osteolysis/osteoarthritis. Most sprains and many type III separations are managed conservatively (sling, activity modification, strengthening); local anesthetic/corticosteroid injection is diagnostic and therapeutic; distal clavicle excision for persistent cases.",
     "source": "Brukner & Khan Ch.17 (acromioclavicular joint injuries; chronic AC joint pain)"
   },
   {
     "id": "bd-5",
     "condition": "Adhesive capsulitis (frozen shoulder)",
     "confidence": "common",
     "mimics": "Diffuse shoulder pain with stiffness and difficulty reaching behind the back or sleeping on the shoulder \u2014 overlaps the infraspinatus 'cannot reach behind back / cannot sleep either side' pattern",
     "distinguishing_feature": "Global restriction of glenohumeral motion \u2014 the hallmark is loss of PASSIVE external rotation with the elbow at the side (with the scapula stabilised), which trigger-point pain does NOT cause. Typically ages 40\u201360, insidious or post-immobilisation onset, associated with diabetes and thyroid disease; passes through painful, stiff, and thawing phases over months. Myofascial restriction is movement- and direction-specific and improves with trigger-point release, whereas capsulitis is a true passive-ROM block.",
     "action": "Examine passive external rotation with the scapula stabilised; exclude glenohumeral arthritis radiographically. Reassurance about the self-limiting course; analgesia, intra-articular corticosteroid in the painful phase, supervised range-of-motion program; arthroscopic capsular release for refractory cases (less effective in diabetes).",
     "source": "Brukner & Khan Ch.17 (shoulder stiffness / adhesive capsulitis)"
   },
   {
     "id": "bd-6",
     "condition": "Cervical radiculopathy (C5\u2013C6) / referred cervicothoracic pain",
     "confidence": "common",
     "mimics": "Neck pain referring to the shoulder and arm with dermatomal sensory or motor change \u2014 overlaps the scalene/scalenus minimus and biceps anterior-arm patterns",
     "distinguishing_feature": "Neck pain radiating into the shoulder and arm with dermatomal paraesthesia, reflex change (e.g. diminished biceps/brachioradialis reflex), and weakness in muscles of a single myotome including ones OUTSIDE the front-of-arm myofascial group; a positive Spurling's (neck extension-rotation reproducing arm symptoms) supports it. The cervical and upper-thoracic spine commonly refer to the shoulder even without prominent neck pain. Scalene/myofascial referral has no fixed dermatomal deficit, normal reflexes, and is reproduced by muscle palpation; test the upper-quarter neurology to separate them.",
     "action": "Full upper-quarter neurological exam with Spurling's and an upper-limb neural tension test; reassess shoulder symptoms after treating any hypomobile cervical/thoracic segment. MRI cervical spine and electrodiagnostics where root signs persist or progress. Treat coexisting scalene and shoulder-girdle trigger points concurrently.",
     "source": "Brukner & Khan Ch.17 (referred pain from cervical/thoracic spine)"
   },
   {
     "id": "bd-7",
     "condition": "Neurogenic thoracic outlet syndrome",
     "confidence": "uncommon",
     "mimics": "Arm/forearm aching and paraesthesia with the nocturnal arm-hanging pattern \u2014 directly overlaps the scalene, scalenus minimus, and subclavius presentations the model scores",
     "distinguishing_feature": "Compression of the brachial plexus (usually the lower trunk) in the costoclavicular space producing arm/forearm aching, ulnar-side paraesthesia, easy fatigue, and symptoms worsened by overhead or sustained arm positions; provoked by the Roos hyperabduction/external-rotation (EAST) and Wright maneuvers, and associated with drooping posture, tight scalene/pectoralis minor, and scapular dyskinesis. Distinguished from the VASCULAR TOS emergency (limb swelling, discoloration, pulse change) by the absence of acute vascular signs. This is the myofascially-entangled, NON-emergent subtype.",
     "action": "Cross-linked to the dedicated page \u2014 see Differential:ThoracicOutletSyndrome for full assessment and management; this entry exists to flag overlap with the scalene/subclavius muscles and to keep the canonical content in one place. In brief: posture and scalene/pectoralis-minor work, scapular stabilisation, and trigger-point treatment; nerve studies and surgical referral for progressive neurological deficit.",
     "source": "Brukner & Khan Ch.17 (thoracic outlet syndrome); cross-link Differential:ThoracicOutletSyndrome"
   },
   {
     "id": "bd-8",
     "condition": "Suprascapular neuropathy",
     "confidence": "uncommon",
     "mimics": "Deep, poorly localised posterior/lateral shoulder pain with shoulder weakness \u2014 overlaps the infraspinatus and supraspinatus contributions to a front-of-shoulder picture",
     "distinguishing_feature": "Deep, poorly localised shoulder pain (often felt posterolaterally or referred to the arm/upper anterior chest) with weakness of abduction and external rotation and visible wasting of supraspinatus and/or infraspinatus. Entrapment at the suprascapular notch affects BOTH muscles; entrapment at the spinoglenoid notch causes ISOLATED infraspinatus wasting (seen in volleyball 'float' servers and from a paralabral cyst arising off a SLAP tear). Trigger-point pain produces no true muscle wasting or denervation weakness.",
     "action": "Inspect for supra-/infraspinatus wasting; test external-rotation and abduction strength; palpate the suprascapular notch. EMG/nerve conduction confirm and localise; MRI to seek a paralabral/spinoglenoid cyst. Usually non-operative (rehabilitation, load management); surgical decompression or cyst excision for progressive weakness or a compressive cyst.",
     "source": "Brukner & Khan Ch.17 (suprascapular nerve entrapment)"
   },
   {
     "id": "bd-9",
     "condition": "Costochondritis / Tietze syndrome / anterior chest-wall pain",
     "confidence": "common",
     "mimics": "Anterior chest pain that can extend toward the front of the shoulder \u2014 the benign musculoskeletal counterpart to the sternalis substernal pattern, and the key contrast to cardiac pain",
     "distinguishing_feature": "Localised anterior chest-wall pain REPRODUCED BY PALPATION of the costochondral/costosternal junctions (Tietze syndrome adds visible/palpable swelling, classically of the 2nd\u20133rd costal cartilage), often worse with deep breathing, coughing, or trunk movement. Reproducibility on palpation and a clear positional/respiratory component point to the chest wall \u2014 but palpable reproducibility does NOT by itself exclude cardiac disease, which must be ruled out first when risk factors or red-flag features are present. Sternalis trigger-point pain is a deep substernal ache reproduced by sternalis/pectoralis palpation and is characteristically movement-INDEPENDENT.",
     "action": "Palpate the costochondral junctions and reproduce the pain; assess respiratory/positional provocation; exclude ACS (see emergency tier) before settling on a chest-wall diagnosis. Reassurance, analgesia/NSAIDs, activity modification; treat coexisting sternalis and pectoralis trigger points.",
     "source": "Chest Pain: Evaluation and Exclusion of MI and Angina StatPearls (NBK557672); Coronary Artery Disease StatPearls (NBK564304, costochondritis as MSK mimic)"
   }
 ]

}

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