DiagnosticTree/LateralEpicondyle: Difference between revisions

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Created page with "{ "model": "bayesian_lr_scoring", "version": "1.0", "region_label": "Lateral Epicondyle Pain", "description": "Probabilistic scoring model for lateral epicondyle / lateral elbow pain. Seven muscles from T&S Vol.1, all primary (bold) referrers to the lateral epicondyle: Supinator, Brachioradialis, Extensor Carpi Radialis, Triceps Brachii (lateral head), Supraspinatus, the ring and little finger fibres of Extensor Digitorum, and Anconeus. Structural differential fr..."
 
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Line 3: Line 3:
   "version": "1.0",
   "version": "1.0",
   "region_label": "Lateral Epicondyle Pain",
   "region_label": "Lateral Epicondyle Pain",
   "description": "Probabilistic scoring model for lateral epicondyle / lateral elbow pain. Seven muscles from T&S Vol.1, all primary (bold) referrers to the lateral epicondyle: Supinator, Brachioradialis, Extensor Carpi Radialis, Triceps Brachii (lateral head), Supraspinatus, the ring and little finger fibres of Extensor Digitorum, and Anconeus. Structural differential from Chung et al. 2025 and standard lateral epicondylitis literature.",
   "description": "Probabilistic scoring model for lateral epicondyle / lateral elbow pain. Eight muscles from T&S Vol.1, all primary (bold) referrers to the lateral epicondyle: Supinator, Brachioradialis, Extensor Carpi Radialis, Triceps Brachii (lateral head), Supraspinatus, the ring and little finger fibres of Extensor Digitorum, Anconeus, and Extensor Carpi Ulnaris. Structural differential from Chung et al. 2025 and standard lateral epicondylitis literature.",
   "thresholds": {
   "thresholds": {
     "early_exit_posterior": 0.55,
     "early_exit_posterior": 0.55,
Line 12: Line 12:
     "supinator": {
     "supinator": {
       "label": "Supinator",
       "label": "Supinator",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Supinator",
       "page": "Muscle:Supinator",
       "key_trp_note": "The supinator is typically the primary driver of the lateral-epicondyle trigger point sequence (supinator -> brachioradialis -> extensor carpi radialis -> finger extensors). It forms a functional twisting unit with the ring and little finger extensors. Can entrap the deep radial (posterior interosseous) nerve - screen for radial tunnel features. Treat the supinator first; the downstream extensor TrPs often resolve.",
       "key_trp_note": "The supinator is typically the primary driver of the lateral-epicondyle trigger point sequence (supinator -> brachioradialis -> extensor carpi radialis -> finger extensors). It forms a functional twisting unit with the ring and little finger extensors. Can entrap the deep radial (posterior interosseous) nerve - screen for radial tunnel features. Treat the supinator first; the downstream extensor TrPs often resolve.",
Line 19: Line 19:
     "brachioradialis": {
     "brachioradialis": {
       "label": "Brachioradialis",
       "label": "Brachioradialis",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Brachioradialis",
       "page": "Muscle:Brachioradialis",
       "key_trp_note": "Part of the lateral extensor-mass spread pattern, second in the typical sequence after the supinator. Refers to the lateral epicondyle and along the dorsoradial forearm to the thumb base. Strongest on resisted elbow flexion with the forearm in neutral (thumb-up) - distinct from biceps (supinated) and brachialis (any position).",
       "key_trp_note": "Part of the lateral extensor-mass spread pattern, second in the typical sequence after the supinator. Refers to the lateral epicondyle and along the dorsoradial forearm to the thumb base. Strongest on resisted elbow flexion with the forearm in neutral (thumb-up) - distinct from biceps (supinated) and brachialis (any position).",
Line 26: Line 26:
     "extensor_carpi_radialis": {
     "extensor_carpi_radialis": {
       "label": "Extensor Carpi Radialis",
       "label": "Extensor Carpi Radialis",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Extensor_Carpi_Radialis",
       "page": "Muscle:Extensor_Carpi_Radialis",
       "key_trp_note": "The radial wrist extensors lie at the heart of the classic tennis-elbow picture - the common extensor origin enthesopathy is secondary to taut-band tension here. Refers to the lateral epicondyle and the dorsoradial wrist and hand. Third in the typical lateral spread sequence. Reproduced by resisted wrist extension (Cozen's test) and gripping.",
       "key_trp_note": "The radial wrist extensors lie at the heart of the classic tennis-elbow picture - the common extensor origin enthesopathy is secondary to taut-band tension here. Refers to the lateral epicondyle and the dorsoradial wrist and hand. Third in the typical lateral spread sequence. Reproduced by resisted wrist extension (Cozen's test) and gripping.",
Line 33: Line 33:
     "triceps_lateral_head": {
     "triceps_lateral_head": {
       "label": "Triceps Brachii (lateral head)",
       "label": "Triceps Brachii (lateral head)",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Triceps_Brachii",
       "page": "Muscle:Triceps_Brachii",
       "key_trp_note": "A trigger point in the lateral head of triceps refers to the lateral epicondyle and the posterior arm. Distinguished from the forearm extensor sources by provocation on resisted elbow EXTENSION (pushing, press-ups) rather than wrist or finger movement, and by posterior upper-arm referral.",
       "key_trp_note": "A trigger point in the lateral head of triceps refers to the lateral epicondyle and the posterior arm. Distinguished from the forearm extensor sources by provocation on resisted elbow EXTENSION (pushing, press-ups) rather than wrist or finger movement, and by posterior upper-arm referral.",
Line 40: Line 40:
     "supraspinatus": {
     "supraspinatus": {
       "label": "Supraspinatus",
       "label": "Supraspinatus",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Supraspinatus",
       "page": "Muscle:Supraspinatus",
       "key_trp_note": "The essential zone is the mid-deltoid (lateral shoulder); the lateral epicondyle is a spillover that uniquely separates supraspinatus from infraspinatus. Consider it when elbow pain is accompanied by shoulder pain. Aggravated by carrying a heavy bag with the arm at the side (sustained humeral-head traction) and by overhead reaching; shoulder clicking that resolves with treatment is characteristic. Seldom isolated - usually with infraspinatus or upper trapezius.",
       "key_trp_note": "The essential zone is the mid-deltoid (lateral shoulder); the lateral epicondyle is a spillover that uniquely separates supraspinatus from infraspinatus. Consider it when elbow pain is accompanied by shoulder pain. Aggravated by carrying a heavy bag with the arm at the side (sustained humeral-head traction) and by overhead reaching; shoulder clicking that resolves with treatment is characteristic. Seldom isolated - usually with infraspinatus or upper trapezius.",
Line 47: Line 47:
     "extensor_digitorum_45": {
     "extensor_digitorum_45": {
       "label": "Extensor Digitorum (ring and little finger fibres)",
       "label": "Extensor Digitorum (ring and little finger fibres)",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Extensor_Digitorum",
       "page": "Muscle:Extensor_Digitorum",
       "key_trp_note": "The ring and little finger extensor fibres are the part of extensor digitorum that refers proximally to the lateral epicondyle - the middle finger fibres do not. Pain also runs down the dorsum of the hand into the ring and little fingers, stopping short of the fingertips. Pain at the 'elbow' on firm handshaking is the cardinal pointer. The finger-flexion test is positive for the affected finger. Almost always accompanied by extensor carpi ulnaris involvement.",
       "key_trp_note": "The ring and little finger extensor fibres are the part of extensor digitorum that refers proximally to the lateral epicondyle - the middle finger fibres do not. Pain also runs down the dorsum of the hand into the ring and little fingers, stopping short of the fingertips. Pain at the 'elbow' on firm handshaking is the cardinal pointer. The finger-flexion test is positive for the affected finger. Almost always accompanied by extensor carpi ulnaris involvement.",
Line 54: Line 54:
     "anconeus": {
     "anconeus": {
       "label": "Anconeus",
       "label": "Anconeus",
       "prior": 0.142857,
       "prior": 0.125,
       "page": "Muscle:Anconeus",
       "page": "Muscle:Anconeus",
       "key_trp_note": "A small posterolateral elbow muscle whose trigger point produces tightly localised pain at and just behind the lateral epicondyle, without the distal forearm or hand referral of the extensor sources. Provoked by resisted elbow extension. Consider it when lateral elbow pain stays strictly local.",
       "key_trp_note": "A small posterolateral elbow muscle whose trigger point produces tightly localised pain at and just behind the lateral epicondyle, without the distal forearm or hand referral of the extensor sources. Provoked by resisted elbow extension. Consider it when lateral elbow pain stays strictly local.",
       "subtitle": "Very LOCAL pain at the lateral epicondyle and just behind it (posterolateral elbow); worse on resisted elbow extension; little or no distal forearm or hand referral"
       "subtitle": "Very LOCAL pain at the lateral epicondyle and just behind it (posterolateral elbow); worse on resisted elbow extension; little or no distal forearm or hand referral"
    },
    "extensor_carpi_ulnaris": {
      "label": "Extensor Carpi Ulnaris",
      "prior": 0.125,
      "page": "Muscle:Extensor_Carpi_Ulnaris",
      "key_trp_note": "The least commonly involved wrist extensor - it seldom develops trigger points from ordinary gripping. Its referral is a focal, well-localised ache at the ULNAR dorsal wrist, distinct from the radial-side pattern of the radial wrist extensors, and it reaches the lateral epicondyle through the common extensor origin. Look for a precipitating cause - fracture, immobilisation in a cast, or a global frozen-shoulder freezing pattern - rather than repetitive use. Almost never active without a coexisting ring/little finger extensor trigger point; examine and treat the two together. Serratus posterior superior can drive it as a satellite.",
      "subtitle": "Focal pain at the ULNAR side of the dorsal wrist (not the radial side); worse on gripping with the wrist turned toward the little-finger side; usually follows trauma, casting, or a frozen shoulder rather than ordinary overuse"
     }
     }
   },
   },
Line 78: Line 85:
             "supraspinatus": 8.0,
             "supraspinatus": 8.0,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 0.4
             "anconeus": 0.4,
            "extensor_carpi_ulnaris": 0.4
           }
           }
         },
         },
Line 92: Line 100:
             "supraspinatus": 1.5,
             "supraspinatus": 1.5,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 1.5
             "anconeus": 1.5,
            "extensor_carpi_ulnaris": 0.4
           }
           }
         },
         },
Line 106: Line 115:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 0.5,
             "extensor_digitorum_45": 0.5,
             "anconeus": 6.5
             "anconeus": 6.5,
            "extensor_carpi_ulnaris": 0.8
           }
           }
         },
         },
Line 120: Line 130:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 2.5,
             "extensor_digitorum_45": 2.5,
             "anconeus": 0.4
             "anconeus": 0.4,
            "extensor_carpi_ulnaris": 2.5
           }
           }
         }
         }
Line 142: Line 153:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 1.5,
             "extensor_digitorum_45": 1.5,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 156: Line 168:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 3.0,
             "extensor_digitorum_45": 3.0,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 3.0
           }
           }
         },
         },
Line 170: Line 183:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 7.0,
             "extensor_digitorum_45": 7.0,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 1.2
           }
           }
         },
         },
Line 184: Line 198:
             "supraspinatus": 0.8,
             "supraspinatus": 0.8,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 4.5
             "anconeus": 4.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 198: Line 213:
             "supraspinatus": 0.6,
             "supraspinatus": 0.6,
             "extensor_digitorum_45": 0.6,
             "extensor_digitorum_45": 0.6,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 212: Line 228:
             "supraspinatus": 7.0,
             "supraspinatus": 7.0,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         }
         }
Line 234: Line 251:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 0.8,
             "extensor_digitorum_45": 0.8,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 248: Line 266:
             "supraspinatus": 0.6,
             "supraspinatus": 0.6,
             "extensor_digitorum_45": 1.5,
             "extensor_digitorum_45": 1.5,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.6
           }
           }
         },
         },
Line 262: Line 281:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 7.0,
             "extensor_digitorum_45": 7.0,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 1.5
          }
        },
        {
          "id": "ulnar_dorsal_wrist",
          "label": "To the LITTLE-FINGER side of the back of the wrist (a focal, well-contained spot)",
          "sublabel": "Ulnar dorsal wrist",
          "lr": {
            "supinator": 0.6,
            "brachioradialis": 0.5,
            "extensor_carpi_radialis": 0.7,
            "triceps_lateral_head": 0.4,
            "supraspinatus": 0.4,
            "extensor_digitorum_45": 1.5,
            "anconeus": 0.5,
            "extensor_carpi_ulnaris": 7.0
           }
           }
         },
         },
Line 276: Line 311:
             "supraspinatus": 5.0,
             "supraspinatus": 5.0,
             "extensor_digitorum_45": 0.5,
             "extensor_digitorum_45": 0.5,
             "anconeus": 0.8
             "anconeus": 0.8,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 290: Line 326:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 0.5,
             "extensor_digitorum_45": 0.5,
             "anconeus": 5.0
             "anconeus": 5.0,
            "extensor_carpi_ulnaris": 1.0
           }
           }
         }
         }
Line 311: Line 348:
             "supraspinatus": 0.6,
             "supraspinatus": 0.6,
             "extensor_digitorum_45": 6.0,
             "extensor_digitorum_45": 6.0,
             "anconeus": 0.8
             "anconeus": 0.8,
            "extensor_carpi_ulnaris": 1.0
           }
           }
         },
         },
Line 324: Line 362:
             "supraspinatus": 1.1,
             "supraspinatus": 1.1,
             "extensor_digitorum_45": 0.3,
             "extensor_digitorum_45": 0.3,
             "anconeus": 1.1
             "anconeus": 1.1,
            "extensor_carpi_ulnaris": 1.0
           }
           }
         }
         }
Line 345: Line 384:
             "supraspinatus": 7.0,
             "supraspinatus": 7.0,
             "extensor_digitorum_45": 0.5,
             "extensor_digitorum_45": 0.5,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 358: Line 398:
             "supraspinatus": 0.2,
             "supraspinatus": 0.2,
             "extensor_digitorum_45": 1.2,
             "extensor_digitorum_45": 1.2,
             "anconeus": 1.2
             "anconeus": 1.2,
            "extensor_carpi_ulnaris": 1.2
           }
           }
         }
         }
Line 379: Line 420:
             "supraspinatus": 0.6,
             "supraspinatus": 0.6,
             "extensor_digitorum_45": 2.5,
             "extensor_digitorum_45": 2.5,
             "anconeus": 0.6
             "anconeus": 0.6,
            "extensor_carpi_ulnaris": 0.6
           }
           }
         },
         },
Line 392: Line 434:
             "supraspinatus": 1.1,
             "supraspinatus": 1.1,
             "extensor_digitorum_45": 0.8,
             "extensor_digitorum_45": 0.8,
             "anconeus": 1.2
             "anconeus": 1.2,
            "extensor_carpi_ulnaris": 1.1
           }
           }
         }
         }
Line 413: Line 456:
             "supraspinatus": 0.5,
             "supraspinatus": 0.5,
             "extensor_digitorum_45": 1.5,
             "extensor_digitorum_45": 1.5,
             "anconeus": 0.6
             "anconeus": 0.6,
            "extensor_carpi_ulnaris": 0.7
           }
           }
         },
         },
Line 426: Line 470:
             "supraspinatus": 1.1,
             "supraspinatus": 1.1,
             "extensor_digitorum_45": 1.0,
             "extensor_digitorum_45": 1.0,
             "anconeus": 1.1
             "anconeus": 1.1,
            "extensor_carpi_ulnaris": 1.1
           }
           }
         }
         }
Line 448: Line 493:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 0.8,
             "extensor_digitorum_45": 0.8,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.5
           }
           }
         },
         },
Line 462: Line 508:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 0.6,
             "extensor_digitorum_45": 0.6,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.6
           }
           }
         },
         },
Line 476: Line 523:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 1.2,
             "extensor_digitorum_45": 1.2,
             "anconeus": 0.6
             "anconeus": 0.6,
            "extensor_carpi_ulnaris": 0.8
           }
           }
         },
         },
Line 490: Line 538:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 7.0,
             "extensor_digitorum_45": 7.0,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 1.0
          }
        },
        {
          "id": "ulnar_dorsal_forearm",
          "label": "A hand's breadth below the epicondyle, close to the sharp dorsal edge of the ulna (a tender spot whose twitch turns the hand toward the little-finger side)",
          "sublabel": "Extensor carpi ulnaris location (about 7-8 cm distal to the epicondyle, near the ulnar border)",
          "lr": {
            "supinator": 0.6,
            "brachioradialis": 0.5,
            "extensor_carpi_radialis": 0.8,
            "triceps_lateral_head": 0.4,
            "supraspinatus": 0.4,
            "extensor_digitorum_45": 1.2,
            "anconeus": 0.6,
            "extensor_carpi_ulnaris": 7.0
           }
           }
         },
         },
Line 504: Line 568:
             "supraspinatus": 1.0,
             "supraspinatus": 1.0,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 0.8
             "anconeus": 0.8,
            "extensor_carpi_ulnaris": 0.4
           }
           }
         },
         },
Line 518: Line 583:
             "supraspinatus": 0.4,
             "supraspinatus": 0.4,
             "extensor_digitorum_45": 0.5,
             "extensor_digitorum_45": 0.5,
             "anconeus": 7.0
             "anconeus": 7.0,
            "extensor_carpi_ulnaris": 0.6
           }
           }
         },
         },
Line 532: Line 598:
             "supraspinatus": 7.0,
             "supraspinatus": 7.0,
             "extensor_digitorum_45": 0.4,
             "extensor_digitorum_45": 0.4,
             "anconeus": 0.5
             "anconeus": 0.5,
            "extensor_carpi_ulnaris": 0.4
           }
           }
         }
         }
Line 647: Line 714:
             "supinator": 0.3,
             "supinator": 0.3,
             "brachioradialis": 6.0
             "brachioradialis": 6.0
          }
        }
      ]
    },
    {
      "id": "pw_ecr_ecu",
      "pair": [
        "extensor_carpi_radialis",
        "extensor_carpi_ulnaris"
      ],
      "text": "Tiebreaker - Extensor Carpi Radialis vs Extensor Carpi Ulnaris",
      "question": "Is the wrist/hand pain on the RADIAL (thumb) side and tied to ordinary gripping, or on the ULNAR (little-finger) side with a history of trauma, casting, or a stiff/frozen shoulder?",
      "sublabel": "Radial wrist extensor (common, overuse) vs ulnar wrist extensor (uncommon, post-trauma/immobilisation)",
      "answers": [
        {
          "id": "radial",
          "label": "Radial-side wrist/hand, ordinary overuse - extensor carpi radialis",
          "lr": {
            "extensor_carpi_radialis": 6.0,
            "extensor_carpi_ulnaris": 0.3
          }
        },
        {
          "id": "ulnar",
          "label": "Ulnar-side wrist, post-trauma/immobilisation or frozen shoulder - extensor carpi ulnaris",
          "lr": {
            "extensor_carpi_radialis": 0.3,
            "extensor_carpi_ulnaris": 6.0
           }
           }
         }
         }
Line 677: Line 772:
         "type": "functional_unit",
         "type": "functional_unit",
         "label": "Radial wrist extensors and finger extensors share the common extensor origin; treat together"
         "label": "Radial wrist extensors and finger extensors share the common extensor origin; treat together"
      },
      {
        "from": "extensor_digitorum_45",
        "to": "extensor_carpi_ulnaris",
        "type": "functional_unit",
        "label": "The ulnar wrist extensor is almost never involved without the ring/little finger extensors; examine and treat them together"
       },
       },
       {
       {
Line 716: Line 817:
       "id": "rf-u1",
       "id": "rf-u1",
       "label": "Posterior interosseous nerve (radial tunnel) palsy",
       "label": "Posterior interosseous nerve (radial tunnel) palsy",
       "question": "Weakness extending the fingers or thumb (finger drop) with preserved wrist extension? Deep aching in the proximal dorsal forearm distal to the lateral epicondyle? Progressive motor loss? NOTE: the supinator can entrap this nerve - progressive weakness needs prompt evaluation, not just TrP treatment.",
       "question": "Weakness extending the fingers or thumb (finger drop) with preserved wrist extension? Deep aching localised more DISTAL than the epicondyle, in the muscle bellies of the proximal forearm, with tenderness over the radial tunnel between brachioradialis and extensor carpi radialis longus? Reproduced by resisted supination and resisted middle-finger extension? Progressive motor loss? NOTE: the posterior interosseous nerve runs under the ECRB fascia and supinator and can be entrapped there - PIN entrapment coexists in up to 15% of tennis-elbow cases; progressive weakness needs prompt evaluation, not just TrP treatment.",
       "source": "Chung et al. 2025 (radial tunnel / PIN syndrome)"
       "source": "Tweedie & Vollans 2024; Buchanan & Varacallo 2023; Chung et al. 2025"
     },
     },
     {
     {
Line 728: Line 829:
       "id": "rf-u3",
       "id": "rf-u3",
       "label": "Osteochondritis dissecans of the capitellum",
       "label": "Osteochondritis dissecans of the capitellum",
       "question": "Adolescent or young throwing athlete or gymnast with lateral elbow pain? Pain on the active radiocapitellar compression test (pronation/supination with the arm extended)? Mechanical catching or locking suggesting a loose body? Radiographs are mandatory in this group.",
       "question": "Is the patient a child or adolescent? Children and adolescents DO NOT get tennis elbow - lateral elbow pain in a skeletally immature patient is osteochondritis dissecans until proven otherwise, especially in throwers or gymnasts who load the elbow in extension. Pain on the active radiocapitellar compression test (pain on forearm rotation with the arm extended)? Mechanical catching or locking suggesting a loose body? Radiographs are mandatory in this group.",
       "source": "Chung et al. 2025"
       "source": "Tweedie & Vollans 2024 (age filter); Chung et al. 2025"
     },
     },
     {
     {
Line 750: Line 851:
       "confidence": "common",
       "confidence": "common",
       "mimics": "The single most common structural diagnosis at the lateral epicondyle - overlaps directly with the radial wrist extensor and finger extensor TrP referral",
       "mimics": "The single most common structural diagnosis at the lateral epicondyle - overlaps directly with the radial wrist extensor and finger extensor TrP referral",
       "distinguishing_feature": "Localised tenderness at the lateral epicondyle / common extensor origin, 1-2 cm distal to the ECRB attachment; positive Cozen's test (pain on resisted wrist extension). Crucially, the epicondylar enthesopathy is frequently SECONDARY to taut-band tension from central TrPs in supinator, brachioradialis, extensor carpi radialis, and the finger extensors - compressing the responsible central TrP reproduces and abolishes the epicondylar pain. A degenerative tendinosis, not inflammation.",
       "distinguishing_feature": "Localised tenderness at the lateral epicondyle / common extensor origin, 1-2 cm distal to the ECRB attachment; positive Cozen's test (pain on resisted wrist extension) and resisted middle-finger extension. The pathognomonic sign (Briggs & Elliott): with the forearm fully pronated and the wrist flexed, extending the elbow produces severe pain over the last 20 degrees of extension as the radial head shears against the ECRB. Crucially, the epicondylar enthesopathy is frequently SECONDARY to taut-band tension from central TrPs in supinator, brachioradialis, the radial wrist extensors, and the finger extensors - compressing the responsible central TrP reproduces and abolishes the epicondylar pain. A degenerative tendinosis, not inflammation; a bursa underlies the ECRB in up to half of surgical cases.",
       "action": "Examine for the central TrP driving the enthesopathy before labelling it isolated epicondylitis. Conservative: load modification, counterforce strap, eccentric loading, TrP inactivation. ~5% coexist with radial tunnel syndrome. Surgery only after 6-9 months of failed conservative care.",
       "action": "Examine for the central TrP driving the enthesopathy before labelling it isolated epicondylitis. Conservative: load modification, counterforce strap, eccentric loading, TrP inactivation. PIN/radial tunnel entrapment coexists in up to 15% of cases. Surgery only after 6-12 months of failed conservative care; repeated steroid injections risk tendon rupture and fatty atrophy.",
       "source": "Chung et al. 2025; standard lateral epicondylitis literature"
       "source": "Briggs & Elliott 1985 (pathognomonic sign, bursa); Buchanan & Varacallo 2023; Chung et al. 2025"
     },
     },
     {
     {
Line 759: Line 860:
       "confidence": "uncommon",
       "confidence": "uncommon",
       "mimics": "Lateral forearm pain - overlaps the supinator TrP zone and is frequently confused with resistant tennis elbow",
       "mimics": "Lateral forearm pain - overlaps the supinator TrP zone and is frequently confused with resistant tennis elbow",
       "distinguishing_feature": "Pain located more DISTAL than the epicondyle (over the radial tunnel, 3-5 cm distal); Cozen's test often negative; pain provoked by resisted supination and resisted middle-finger/thumb extension; tenderness over the radial neck / arcade of Frohse. The supinator's own taut bands can both mimic and cause this entrapment.",
       "distinguishing_feature": "Pain localised more DISTALLY than the epicondyle - over the muscle bellies arising from the common extensor origin, tender over the radial tunnel which is palpated between brachioradialis and extensor carpi radialis longus (the brachioradialis lifts on resisted isometric elbow flexion in mid-prone, marking the tunnel's radial border). Cozen's test often negative or only weakly positive; pain provoked by direct compression over the nerve and by resisted supination. Found in repetitive-task workers (musicians, rowers, factory work). The PIN runs under the ECRB fascia and supinator - the supinator's own taut bands can both mimic and cause this entrapment.",
       "action": "Distinguish from epicondylitis by the distal pain location and provocation pattern. Inactivate supinator TrPs first; if motor weakness or progressive symptoms, EMG/NCS and surgical decompression. ~5% coexist with lateral epicondylitis.",
       "action": "Distinguish from epicondylitis by the distal pain location, the radial-tunnel tenderness, and the provocation pattern. Inactivate supinator TrPs first; a diagnostic local-anaesthetic block around the radial nerve can confirm. If motor weakness or progressive symptoms, EMG/NCS and surgical decompression (release of ECRB fascia, crossing vessels, and supinator). Coexists in up to 15% of tennis-elbow cases.",
       "source": "Chung et al. 2025"
       "source": "Tweedie & Vollans 2024; Buchanan & Varacallo 2023; Chung et al. 2025"
     },
     },
     {
     {
Line 783: Line 884:
     {
     {
       "id": "bd-5",
       "id": "bd-5",
       "condition": "Intra-articular loose body / radiocapitellar plica",
       "condition": "Synovial plica syndrome / intra-articular loose body",
       "confidence": "uncommon",
       "confidence": "uncommon",
       "mimics": "Lateral elbow pain with a painful click - can overlap supinator and anconeus presentations",
       "mimics": "Lateral elbow pain with clicking, snapping, or occasional locking - can overlap supinator and anconeus presentations",
       "distinguishing_feature": "Painful click or clunk at the end of supination/extension with the forearm supinated; point of maximum tenderness posterior to the radiocapitellar joint (distinguishing it from epicondylitis); episodic locking. TrP pain has no joint-line click.",
       "distinguishing_feature": "Insidious clicking or snapping felt at the lateral elbow, sometimes with locking. A symptomatic plica is provoked by the flexion-pronation manoeuvre: the elbow is flexed, the forearm maximally pronated, then passively extended with pressure over the posterolateral radiocapitellar joint and a valgus force - positive when snapping/pain occurs at around 30 degrees off full extension. Synovial plicae are present in over 86% of normal elbows, so MRI is often normal and the diagnosis is largely clinical and by exclusion. A loose body gives a painful click at end-supination/extension with point tenderness posterior to the radiocapitellar joint. TrP pain has no joint-line click.",
       "action": "X-ray and CT for loose bodies; MRI for plica. Arthroscopic excision if mechanical symptoms persist.",
       "action": "Radiograph to exclude degenerative change; dynamic ultrasound to assess the click. Rest, anti-inflammatories, activity modification first; arthroscopic excision/debridement of the symptomatic plica (usually posterolateral) if refractory - early arthroscopy is advocated to prevent secondary radiocapitellar chondromalacia from plica kissing lesions.",
       "source": "Chung et al. 2025"
       "source": "Tweedie & Vollans 2024; Chung et al. 2025"
     },
     },
     {
     {
Line 801: Line 902:
     {
     {
       "id": "bd-7",
       "id": "bd-7",
       "condition": "Radiocapitellar osteoarthritis",
       "condition": "Radiocapitellar joint osteoarthritis",
      "confidence": "uncommon",
      "mimics": "Resistant lateral elbow pain on forearm rotation - a NORMAL radiograph commonly leads to mislabelling as persistent lateral epicondylitis",
      "distinguishing_feature": "The grip-and-grind (loaded supination) test is strongly positive: with passive unloaded rotation 80% of force passes through the ulnohumeral joint and there may be no pain, but with a firm grip 80% transfers to the radiocapitellar joint, reproducing pain and crepitus. End-range pain at flexion/extension extremes (osteophytes) but a pain-free through-range (ulnohumeral joint spared). Tennis-elbow provocation may be mildly positive, misleadingly. Typically males in the 4th-5th decade in moderate-to-heavy manual work; carrying angle may increase as the lateral column shortens.",
      "action": "Grip-and-grind test; X-ray (may be normal early - do not let this exclude the diagnosis); CT/MRI for cartilage wear in the radiocapitellar and lateral ulnohumeral compartments. Surgical ladder from arthroscopic debridement/arthrolysis through radial head excision to radiocapitellar arthroplasty. TrPs are independently treatable and frequently coexist.",
      "source": "Tweedie & Vollans 2024 (grip-and-grind, demographics); Chung et al. 2025"
    },
    {
      "id": "bd-9",
      "condition": "Snapping annular ligament",
       "confidence": "rare",
       "confidence": "rare",
       "mimics": "Lateral elbow pain on forearm rotation, particularly in older or post-traumatic patients",
       "mimics": "Anterolateral elbow snapping that can be mistaken for a supinator or mechanical TrP click",
       "distinguishing_feature": "Painful crepitus and a painful sound at the end of extension with the forearm supinated; tenderness posterior to the radiocapitellar joint; radiological joint-space and osteophyte changes. TrP pain spares the joint line and produces no radiological change.",
       "distinguishing_feature": "An uncomfortable snap located anterolaterally, typically occurring when moving from extension to flexion (and reproducible by the patient), often after prior injury to the lateral ligament complex. The thickened or displaced annular ligament subluxes over the radial head. Static imaging is usually normal; dynamic ultrasound is diagnostic, showing the ligament snapping over the radial head. TrP pain produces no ligamentous snap over the radial head.",
       "action": "X-ray; CT if surgical planning. Manage the arthritis; TrPs are independently treatable and frequently coexist.",
       "action": "X-ray to confirm absence of deformity, then dynamic ultrasound. If symptomatic and refractory, arthroscopic partial division of the annular ligament to lengthen it usually resolves the snapping.",
       "source": "Chung et al. 2025"
       "source": "Tweedie & Vollans 2024"
     },
     },
     {
     {

Latest revision as of 05:43, 6 June 2026

{ 

 "model": "bayesian_lr_scoring",
 "version": "1.0",
 "region_label": "Lateral Epicondyle Pain",
 "description": "Probabilistic scoring model for lateral epicondyle / lateral elbow pain. Eight muscles from T&S Vol.1, all primary (bold) referrers to the lateral epicondyle: Supinator, Brachioradialis, Extensor Carpi Radialis, Triceps Brachii (lateral head), Supraspinatus, the ring and little finger fibres of Extensor Digitorum, Anconeus, and Extensor Carpi Ulnaris. Structural differential from Chung et al. 2025 and standard lateral epicondylitis literature.",
 "thresholds": {
   "early_exit_posterior": 0.55,
   "early_exit_gap": 0.18,
   "pairwise_trigger": 0.15
 },
 "muscles": {
   "supinator": {
     "label": "Supinator",
     "prior": 0.125,
     "page": "Muscle:Supinator",
     "key_trp_note": "The supinator is typically the primary driver of the lateral-epicondyle trigger point sequence (supinator -> brachioradialis -> extensor carpi radialis -> finger extensors). It forms a functional twisting unit with the ring and little finger extensors. Can entrap the deep radial (posterior interosseous) nerve - screen for radial tunnel features. Treat the supinator first; the downstream extensor TrPs often resolve.",
     "subtitle": "Lateral epicondyle and dorsal web/thumb base; the typical first muscle in the lateral-elbow spread; worse on resisted supination and forearm twisting (jars, doorknobs); may entrap the radial nerve"
   },
   "brachioradialis": {
     "label": "Brachioradialis",
     "prior": 0.125,
     "page": "Muscle:Brachioradialis",
     "key_trp_note": "Part of the lateral extensor-mass spread pattern, second in the typical sequence after the supinator. Refers to the lateral epicondyle and along the dorsoradial forearm to the thumb base. Strongest on resisted elbow flexion with the forearm in neutral (thumb-up) - distinct from biceps (supinated) and brachialis (any position).",
     "subtitle": "Lateral epicondyle and dorsal forearm to the base of the thumb; worse on resisted elbow flexion in the mid-prone (thumb-up) position and on gripping/twisting work"
   },
   "extensor_carpi_radialis": {
     "label": "Extensor Carpi Radialis",
     "prior": 0.125,
     "page": "Muscle:Extensor_Carpi_Radialis",
     "key_trp_note": "The radial wrist extensors lie at the heart of the classic tennis-elbow picture - the common extensor origin enthesopathy is secondary to taut-band tension here. Refers to the lateral epicondyle and the dorsoradial wrist and hand. Third in the typical lateral spread sequence. Reproduced by resisted wrist extension (Cozen's test) and gripping.",
     "subtitle": "Lateral epicondyle and the dorsoradial wrist / back of the hand; worse on resisted wrist extension and gripping; the classic 'tennis elbow' enthesis source"
   },
   "triceps_lateral_head": {
     "label": "Triceps Brachii (lateral head)",
     "prior": 0.125,
     "page": "Muscle:Triceps_Brachii",
     "key_trp_note": "A trigger point in the lateral head of triceps refers to the lateral epicondyle and the posterior arm. Distinguished from the forearm extensor sources by provocation on resisted elbow EXTENSION (pushing, press-ups) rather than wrist or finger movement, and by posterior upper-arm referral.",
     "subtitle": "Lateral epicondyle and the back of the upper arm; worse on pushing or resisted elbow extension; a posterior-arm source that reaches the lateral epicondyle"
   },
   "supraspinatus": {
     "label": "Supraspinatus",
     "prior": 0.125,
     "page": "Muscle:Supraspinatus",
     "key_trp_note": "The essential zone is the mid-deltoid (lateral shoulder); the lateral epicondyle is a spillover that uniquely separates supraspinatus from infraspinatus. Consider it when elbow pain is accompanied by shoulder pain. Aggravated by carrying a heavy bag with the arm at the side (sustained humeral-head traction) and by overhead reaching; shoulder clicking that resolves with treatment is characteristic. Seldom isolated - usually with infraspinatus or upper trapezius.",
     "subtitle": "Mid-deltoid (lateral shoulder) ache that SPILLS to the lateral epicondyle; worse carrying a heavy bag at the side and on overhead reaching; shoulder may click"
   },
   "extensor_digitorum_45": {
     "label": "Extensor Digitorum (ring and little finger fibres)",
     "prior": 0.125,
     "page": "Muscle:Extensor_Digitorum",
     "key_trp_note": "The ring and little finger extensor fibres are the part of extensor digitorum that refers proximally to the lateral epicondyle - the middle finger fibres do not. Pain also runs down the dorsum of the hand into the ring and little fingers, stopping short of the fingertips. Pain at the 'elbow' on firm handshaking is the cardinal pointer. The finger-flexion test is positive for the affected finger. Almost always accompanied by extensor carpi ulnaris involvement.",
     "subtitle": "Lateral epicondyle PLUS pain down the back of the hand into the ring and little fingers (stopping short of the fingertips); pain at the elbow on firm handshaking"
   },
   "anconeus": {
     "label": "Anconeus",
     "prior": 0.125,
     "page": "Muscle:Anconeus",
     "key_trp_note": "A small posterolateral elbow muscle whose trigger point produces tightly localised pain at and just behind the lateral epicondyle, without the distal forearm or hand referral of the extensor sources. Provoked by resisted elbow extension. Consider it when lateral elbow pain stays strictly local.",
     "subtitle": "Very LOCAL pain at the lateral epicondyle and just behind it (posterolateral elbow); worse on resisted elbow extension; little or no distal forearm or hand referral"
   },
   "extensor_carpi_ulnaris": {
     "label": "Extensor Carpi Ulnaris",
     "prior": 0.125,
     "page": "Muscle:Extensor_Carpi_Ulnaris",
     "key_trp_note": "The least commonly involved wrist extensor - it seldom develops trigger points from ordinary gripping. Its referral is a focal, well-localised ache at the ULNAR dorsal wrist, distinct from the radial-side pattern of the radial wrist extensors, and it reaches the lateral epicondyle through the common extensor origin. Look for a precipitating cause - fracture, immobilisation in a cast, or a global frozen-shoulder freezing pattern - rather than repetitive use. Almost never active without a coexisting ring/little finger extensor trigger point; examine and treat the two together. Serratus posterior superior can drive it as a satellite.",
     "subtitle": "Focal pain at the ULNAR side of the dorsal wrist (not the radial side); worse on gripping with the wrist turned toward the little-finger side; usually follows trauma, casting, or a frozen shoulder rather than ordinary overuse"
   }
 },
 "questions": [
   {
     "id": "q_extent",
     "text": "What is the overall extent of the pain around the lateral elbow?",
     "sublabel": "Choose the pattern that best fits the whole picture",
     "type": "choice",
     "answers": [
       {
         "id": "shoulder_to_elbow",
         "label": "Starts at the SHOULDER (lateral/mid-deltoid) and spills down to the lateral elbow",
         "sublabel": "Shoulder pain is primary; elbow is the far end",
         "lr": {
           "supinator": 0.4,
           "brachioradialis": 0.4,
           "extensor_carpi_radialis": 0.4,
           "triceps_lateral_head": 0.8,
           "supraspinatus": 8.0,
           "extensor_digitorum_45": 0.4,
           "anconeus": 0.4,
           "extensor_carpi_ulnaris": 0.4
         }
       },
       {
         "id": "posterior_arm_to_elbow",
         "label": "Back of the UPPER ARM down to the lateral elbow",
         "sublabel": "Posterior arm component above the elbow",
         "lr": {
           "supinator": 0.5,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.5,
           "triceps_lateral_head": 6.5,
           "supraspinatus": 1.5,
           "extensor_digitorum_45": 0.4,
           "anconeus": 1.5,
           "extensor_carpi_ulnaris": 0.4
         }
       },
       {
         "id": "local_elbow_only",
         "label": "Tightly LOCAL at and just behind the lateral epicondyle; no spread",
         "sublabel": "Pain stays at the bony point",
         "lr": {
           "supinator": 0.7,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 1.2,
           "triceps_lateral_head": 0.8,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 0.5,
           "anconeus": 6.5,
           "extensor_carpi_ulnaris": 0.8
         }
       },
       {
         "id": "elbow_into_forearm_hand",
         "label": "Lateral elbow running DOWN the forearm into the wrist or fingers",
         "sublabel": "Distal spread below the elbow",
         "lr": {
           "supinator": 2.5,
           "brachioradialis": 2.5,
           "extensor_carpi_radialis": 2.5,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 2.5,
           "anconeus": 0.4,
           "extensor_carpi_ulnaris": 2.5
         }
       }
     ]
   },
   {
     "id": "q_provocation",
     "text": "Which movement most reliably reproduces the pain?",
     "sublabel": "Choose the single strongest aggravator",
     "type": "choice",
     "answers": [
       {
         "id": "resisted_supination",
         "label": "Resisted supination / forceful forearm twisting (jar lids, doorknobs, screwdriver)",
         "sublabel": "Turning the palm up against resistance",
         "lr": {
           "supinator": 7.0,
           "brachioradialis": 1.5,
           "extensor_carpi_radialis": 0.8,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 1.5,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "resisted_wrist_ext",
         "label": "Resisted wrist extension or gripping (lifting with palm down, backhand)",
         "sublabel": "Cocking the wrist back against resistance",
         "lr": {
           "supinator": 0.8,
           "brachioradialis": 1.2,
           "extensor_carpi_radialis": 7.0,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 3.0,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 3.0
         }
       },
       {
         "id": "resisted_finger_ext",
         "label": "Resisted finger extension / firm gripping that pulls at the ring and little fingers",
         "sublabel": "Straightening the fingers against resistance",
         "lr": {
           "supinator": 1.2,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 1.5,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 7.0,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 1.2
         }
       },
       {
         "id": "resisted_elbow_ext",
         "label": "Pushing or straightening the elbow against resistance (press-ups, dips)",
         "sublabel": "Forceful elbow extension",
         "lr": {
           "supinator": 0.5,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 0.5,
           "triceps_lateral_head": 6.0,
           "supraspinatus": 0.8,
           "extensor_digitorum_45": 0.4,
           "anconeus": 4.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "resisted_elbow_flex_neutral",
         "label": "Resisted elbow bending with the thumb pointing up (mid-prone lifting)",
         "sublabel": "Elbow flexion in the neutral forearm position",
         "lr": {
           "supinator": 1.0,
           "brachioradialis": 7.0,
           "extensor_carpi_radialis": 1.0,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.6,
           "extensor_digitorum_45": 0.6,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "carry_overhead",
         "label": "Carrying a heavy bag at the side, or reaching/lifting overhead",
         "sublabel": "Sustained shoulder load",
         "lr": {
           "supinator": 0.5,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.5,
           "triceps_lateral_head": 0.8,
           "supraspinatus": 7.0,
           "extensor_digitorum_45": 0.4,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       }
     ]
   },
   {
     "id": "q_referral",
     "text": "If the pain travels away from the elbow, where does it go?",
     "sublabel": "Direction of spread",
     "type": "choice",
     "answers": [
       {
         "id": "thumb_web",
         "label": "Across the dorsal forearm to the web and base of the thumb",
         "sublabel": "Dorsoradial to thumb base",
         "lr": {
           "supinator": 5.0,
           "brachioradialis": 3.0,
           "extensor_carpi_radialis": 1.5,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 0.8,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "dorsoradial_wrist",
         "label": "Down the back of the forearm to the radial (thumb-side) wrist and hand",
         "sublabel": "Dorsoradial wrist/hand",
         "lr": {
           "supinator": 1.2,
           "brachioradialis": 2.5,
           "extensor_carpi_radialis": 5.0,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.6,
           "extensor_digitorum_45": 1.5,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.6
         }
       },
       {
         "id": "ring_little_fingers",
         "label": "Down the back of the hand into the ring and little fingers (not the fingertips)",
         "sublabel": "4th/5th dorsal fingers",
         "lr": {
           "supinator": 0.8,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 1.2,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 7.0,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 1.5
         }
       },
       {
         "id": "ulnar_dorsal_wrist",
         "label": "To the LITTLE-FINGER side of the back of the wrist (a focal, well-contained spot)",
         "sublabel": "Ulnar dorsal wrist",
         "lr": {
           "supinator": 0.6,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.7,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 1.5,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 7.0
         }
       },
       {
         "id": "up_to_shoulder",
         "label": "Upward, toward the lateral shoulder or upper arm",
         "sublabel": "Proximal toward shoulder/arm",
         "lr": {
           "supinator": 0.5,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.5,
           "triceps_lateral_head": 3.0,
           "supraspinatus": 5.0,
           "extensor_digitorum_45": 0.5,
           "anconeus": 0.8,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "no_spread",
         "label": "It does not travel - pain stays at the lateral elbow",
         "sublabel": "No referral",
         "lr": {
           "supinator": 0.7,
           "brachioradialis": 0.7,
           "extensor_carpi_radialis": 0.9,
           "triceps_lateral_head": 1.0,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 0.5,
           "anconeus": 5.0,
           "extensor_carpi_ulnaris": 1.0
         }
       }
     ]
   },
   {
     "id": "q_handshake",
     "text": "Does a firm handshake or hard grip produce pain felt at the ELBOW (not just the hand)?",
     "sublabel": "Cardinal pointer for the ring/little finger extensor fibres",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes - a firm handshake sends pain to the lateral elbow",
         "lr": {
           "supinator": 1.0,
           "brachioradialis": 0.8,
           "extensor_carpi_radialis": 1.2,
           "triceps_lateral_head": 0.6,
           "supraspinatus": 0.6,
           "extensor_digitorum_45": 6.0,
           "anconeus": 0.8,
           "extensor_carpi_ulnaris": 1.0
         }
       },
       {
         "id": "no",
         "label": "No - gripping does not refer pain to the elbow",
         "lr": {
           "supinator": 1.1,
           "brachioradialis": 1.1,
           "extensor_carpi_radialis": 1.0,
           "triceps_lateral_head": 1.1,
           "supraspinatus": 1.1,
           "extensor_digitorum_45": 0.3,
           "anconeus": 1.1,
           "extensor_carpi_ulnaris": 1.0
         }
       }
     ]
   },
   {
     "id": "q_shoulder",
     "text": "Is there accompanying shoulder pain, shoulder clicking, or pain made worse by carrying a heavy bag?",
     "sublabel": "Supraspinatus screen - the lateral-epicondyle spillover comes from the shoulder",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes - shoulder pain/clicking or heavy-bag aggravation is present",
         "lr": {
           "supinator": 0.5,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.5,
           "triceps_lateral_head": 0.9,
           "supraspinatus": 7.0,
           "extensor_digitorum_45": 0.5,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "no",
         "label": "No - no shoulder component",
         "lr": {
           "supinator": 1.2,
           "brachioradialis": 1.2,
           "extensor_carpi_radialis": 1.2,
           "triceps_lateral_head": 1.1,
           "supraspinatus": 0.2,
           "extensor_digitorum_45": 1.2,
           "anconeus": 1.2,
           "extensor_carpi_ulnaris": 1.2
         }
       }
     ]
   },
   {
     "id": "q_twisting",
     "text": "Is the pain strongly linked to twisting tasks - opening jars, turning doorknobs or keys, using a screwdriver?",
     "sublabel": "The supinator + ring/little finger extensor twisting unit",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes - twisting tasks are the clear aggravator",
         "lr": {
           "supinator": 5.0,
           "brachioradialis": 1.5,
           "extensor_carpi_radialis": 1.0,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.6,
           "extensor_digitorum_45": 2.5,
           "anconeus": 0.6,
           "extensor_carpi_ulnaris": 0.6
         }
       },
       {
         "id": "no",
         "label": "No - twisting is not the main trigger",
         "lr": {
           "supinator": 0.4,
           "brachioradialis": 1.0,
           "extensor_carpi_radialis": 1.1,
           "triceps_lateral_head": 1.2,
           "supraspinatus": 1.1,
           "extensor_digitorum_45": 0.8,
           "anconeus": 1.2,
           "extensor_carpi_ulnaris": 1.1
         }
       }
     ]
   },
   {
     "id": "q_radial_nerve",
     "text": "Are there any radial-nerve features - aching deeper and more DISTAL than the epicondyle, or weakness extending the fingers/thumb?",
     "sublabel": "Radial tunnel / posterior interosseous screen - the supinator can entrap this nerve",
     "type": "binary",
     "answers": [
       {
         "id": "yes",
         "label": "Yes - deep aching distal to the epicondyle and/or finger-extension weakness",
         "lr": {
           "supinator": 5.5,
           "brachioradialis": 1.0,
           "extensor_carpi_radialis": 0.8,
           "triceps_lateral_head": 0.5,
           "supraspinatus": 0.5,
           "extensor_digitorum_45": 1.5,
           "anconeus": 0.6,
           "extensor_carpi_ulnaris": 0.7
         }
       },
       {
         "id": "no",
         "label": "No - pain is at the epicondyle level; no extensor weakness",
         "lr": {
           "supinator": 0.7,
           "brachioradialis": 1.1,
           "extensor_carpi_radialis": 1.1,
           "triceps_lateral_head": 1.1,
           "supraspinatus": 1.1,
           "extensor_digitorum_45": 1.0,
           "anconeus": 1.1,
           "extensor_carpi_ulnaris": 1.1
         }
       }
     ]
   },
   {
     "id": "q_palpation",
     "text": "Where does firm palpation most precisely reproduce the familiar pain?",
     "sublabel": "The reproducing tender point - the most specific localiser",
     "type": "choice",
     "answers": [
       {
         "id": "deep_below_radial_head",
         "label": "Deep in the muscle just below the radial head / over the supinator",
         "sublabel": "Supinator location (radial tunnel zone)",
         "lr": {
           "supinator": 7.0,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 0.7,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 0.8,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.5
         }
       },
       {
         "id": "upper_dorsoradial_forearm",
         "label": "In the muscle ridge along the upper dorsoradial forearm (thumb-up flexor-extensor wad)",
         "sublabel": "Brachioradialis location",
         "lr": {
           "supinator": 0.7,
           "brachioradialis": 7.0,
           "extensor_carpi_radialis": 1.5,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 0.6,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.6
         }
       },
       {
         "id": "radial_wrist_extensor_mass",
         "label": "Just distal to the epicondyle in the radial wrist-extensor mass",
         "sublabel": "Extensor carpi radialis location",
         "lr": {
           "supinator": 0.8,
           "brachioradialis": 1.5,
           "extensor_carpi_radialis": 7.0,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 1.2,
           "anconeus": 0.6,
           "extensor_carpi_ulnaris": 0.8
         }
       },
       {
         "id": "mid_extensor_45",
         "label": "Mid-forearm extensor mass toward the ulnar side (ring/little finger extensor fibres)",
         "sublabel": "Extensor digitorum 4th/5th location",
         "lr": {
           "supinator": 0.8,
           "brachioradialis": 0.6,
           "extensor_carpi_radialis": 1.0,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 7.0,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 1.0
         }
       },
       {
         "id": "ulnar_dorsal_forearm",
         "label": "A hand's breadth below the epicondyle, close to the sharp dorsal edge of the ulna (a tender spot whose twitch turns the hand toward the little-finger side)",
         "sublabel": "Extensor carpi ulnaris location (about 7-8 cm distal to the epicondyle, near the ulnar border)",
         "lr": {
           "supinator": 0.6,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.8,
           "triceps_lateral_head": 0.4,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 1.2,
           "anconeus": 0.6,
           "extensor_carpi_ulnaris": 7.0
         }
       },
       {
         "id": "posterior_arm_triceps",
         "label": "In the back of the upper arm (lateral head of triceps), above the elbow",
         "sublabel": "Triceps lateral head location",
         "lr": {
           "supinator": 0.4,
           "brachioradialis": 0.4,
           "extensor_carpi_radialis": 0.4,
           "triceps_lateral_head": 7.0,
           "supraspinatus": 1.0,
           "extensor_digitorum_45": 0.4,
           "anconeus": 0.8,
           "extensor_carpi_ulnaris": 0.4
         }
       },
       {
         "id": "posterolateral_olecranon",
         "label": "Tightly over the posterolateral elbow just behind the epicondyle (anconeus triangle)",
         "sublabel": "Anconeus location",
         "lr": {
           "supinator": 0.6,
           "brachioradialis": 0.5,
           "extensor_carpi_radialis": 0.8,
           "triceps_lateral_head": 0.9,
           "supraspinatus": 0.4,
           "extensor_digitorum_45": 0.5,
           "anconeus": 7.0,
           "extensor_carpi_ulnaris": 0.6
         }
       },
       {
         "id": "mid_deltoid_shoulder",
         "label": "Up in the shoulder (supraspinous fossa above the scapular spine / mid-deltoid)",
         "sublabel": "Supraspinatus location",
         "lr": {
           "supinator": 0.4,
           "brachioradialis": 0.4,
           "extensor_carpi_radialis": 0.4,
           "triceps_lateral_head": 0.8,
           "supraspinatus": 7.0,
           "extensor_digitorum_45": 0.4,
           "anconeus": 0.5,
           "extensor_carpi_ulnaris": 0.4
         }
       }
     ]
   }
 ],
 "pairwise": [
   {
     "id": "pw_sup_ecr",
     "pair": [
       "supinator",
       "extensor_carpi_radialis"
     ],
     "text": "Tiebreaker - Supinator vs Extensor Carpi Radialis",
     "question": "Is the pain reproduced more by resisted SUPINATION / twisting, or by resisted WRIST EXTENSION / gripping?",
     "sublabel": "Twisting source vs wrist-extension source",
     "answers": [
       {
         "id": "supination",
         "label": "Resisted supination / twisting dominates - supinator",
         "lr": {
           "supinator": 6.0,
           "extensor_carpi_radialis": 0.3
         }
       },
       {
         "id": "wrist_ext",
         "label": "Resisted wrist extension / gripping dominates - extensor carpi radialis",
         "lr": {
           "supinator": 0.3,
           "extensor_carpi_radialis": 6.0
         }
       }
     ]
   },
   {
     "id": "pw_ecr_edc",
     "pair": [
       "extensor_carpi_radialis",
       "extensor_digitorum_45"
     ],
     "text": "Tiebreaker - Extensor Carpi Radialis vs Extensor Digitorum (ring/little fingers)",
     "question": "Does the distal pain go to the radial WRIST, or down into the ring and little FINGERS with elbow pain on handshaking?",
     "sublabel": "Wrist extensor vs finger extensor",
     "answers": [
       {
         "id": "wrist",
         "label": "Radial wrist/hand, resisted wrist extension - extensor carpi radialis",
         "lr": {
           "extensor_carpi_radialis": 6.0,
           "extensor_digitorum_45": 0.3
         }
       },
       {
         "id": "fingers",
         "label": "Ring/little fingers, elbow pain on handshake - extensor digitorum",
         "lr": {
           "extensor_carpi_radialis": 0.3,
           "extensor_digitorum_45": 6.0
         }
       }
     ]
   },
   {
     "id": "pw_tri_anc",
     "pair": [
       "triceps_lateral_head",
       "anconeus"
     ],
     "text": "Tiebreaker - Triceps (lateral head) vs Anconeus",
     "question": "Does the pain extend up the back of the UPPER ARM, or stay tightly LOCAL at the posterolateral elbow?",
     "sublabel": "Posterior arm source vs strictly local source",
     "answers": [
       {
         "id": "upper_arm",
         "label": "Extends up the posterior upper arm - triceps lateral head",
         "lr": {
           "triceps_lateral_head": 6.0,
           "anconeus": 0.3
         }
       },
       {
         "id": "local",
         "label": "Stays tightly local at the posterolateral elbow - anconeus",
         "lr": {
           "triceps_lateral_head": 0.3,
           "anconeus": 6.0
         }
       }
     ]
   },
   {
     "id": "pw_sup_br",
     "pair": [
       "supinator",
       "brachioradialis"
     ],
     "text": "Tiebreaker - Supinator vs Brachioradialis",
     "question": "Is it provoked by resisted SUPINATION / twisting, or by resisted elbow BENDING with the thumb up?",
     "sublabel": "Supination source vs mid-prone elbow flexor source",
     "answers": [
       {
         "id": "supination",
         "label": "Resisted supination / twisting - supinator",
         "lr": {
           "supinator": 6.0,
           "brachioradialis": 0.3
         }
       },
       {
         "id": "elbow_flex",
         "label": "Resisted elbow flexion thumb-up - brachioradialis",
         "lr": {
           "supinator": 0.3,
           "brachioradialis": 6.0
         }
       }
     ]
   },
   {
     "id": "pw_ecr_ecu",
     "pair": [
       "extensor_carpi_radialis",
       "extensor_carpi_ulnaris"
     ],
     "text": "Tiebreaker - Extensor Carpi Radialis vs Extensor Carpi Ulnaris",
     "question": "Is the wrist/hand pain on the RADIAL (thumb) side and tied to ordinary gripping, or on the ULNAR (little-finger) side with a history of trauma, casting, or a stiff/frozen shoulder?",
     "sublabel": "Radial wrist extensor (common, overuse) vs ulnar wrist extensor (uncommon, post-trauma/immobilisation)",
     "answers": [
       {
         "id": "radial",
         "label": "Radial-side wrist/hand, ordinary overuse - extensor carpi radialis",
         "lr": {
           "extensor_carpi_radialis": 6.0,
           "extensor_carpi_ulnaris": 0.3
         }
       },
       {
         "id": "ulnar",
         "label": "Ulnar-side wrist, post-trauma/immobilisation or frozen shoulder - extensor carpi ulnaris",
         "lr": {
           "extensor_carpi_radialis": 0.3,
           "extensor_carpi_ulnaris": 6.0
         }
       }
     ]
   }
 ],
 "treatment_dag": {
   "edges": [
     {
       "from": "supinator",
       "to": "brachioradialis",
       "type": "key_satellite",
       "label": "Supinator is the typical primary driver of the lateral-elbow spread; treat first"
     },
     {
       "from": "supinator",
       "to": "extensor_carpi_radialis",
       "type": "key_satellite",
       "label": "Supinator drives the downstream radial wrist extensor TrPs"
     },
     {
       "from": "supinator",
       "to": "extensor_digitorum_45",
       "type": "key_satellite",
       "label": "Supinator and the ring/little finger extensors form a twisting unit; treat the supinator first"
     },
     {
       "from": "extensor_carpi_radialis",
       "to": "extensor_digitorum_45",
       "type": "functional_unit",
       "label": "Radial wrist extensors and finger extensors share the common extensor origin; treat together"
     },
     {
       "from": "extensor_digitorum_45",
       "to": "extensor_carpi_ulnaris",
       "type": "functional_unit",
       "label": "The ulnar wrist extensor is almost never involved without the ring/little finger extensors; examine and treat them together"
     },
     {
       "from": "triceps_lateral_head",
       "to": "anconeus",
       "type": "functional_unit",
       "label": "Triceps and anconeus act together in elbow extension; examine both"
     },
     {
       "from": "supraspinatus",
       "to": "triceps_lateral_head",
       "type": "secondary_load",
       "label": "Shoulder-driven referral; address the supraspinatus source before chasing the elbow"
     }
   ],
   "edge_type_labels": {
     "key_satellite": "Treat first - key TrP driving satellite",
     "functional_unit": "Treat concurrently in same session",
     "secondary_load": "Treat after primary resolves",
     "antagonist_risk": "Treat in alternating cycles - reactive activation risk"
   }
 },
 "emergency": [
   {
     "id": "rf-e1",
     "label": "Acute compartment syndrome of the forearm",
     "question": "Severe, disproportionate, worsening forearm pain unrelieved by rest? Pain sharply increased by passive finger or wrist flexion? Tense or woody forearm? Paraesthesia or pallor of the hand? Recent fracture, crush, or tight cast?",
     "source": "Standard limb emergency screen"
   },
   {
     "id": "rf-e2",
     "label": "Septic arthritis of the elbow / radiocapitellar joint",
     "question": "Acutely hot, swollen, exquisitely tender elbow with severe restriction of all movement and forearm rotation? Fever or systemically unwell? Recent bacteraemia, penetrating injury, IV drug use, or immunosuppression?",
     "source": "Standard joint-sepsis screen"
   }
 ],
 "urgent": [
   {
     "id": "rf-u1",
     "label": "Posterior interosseous nerve (radial tunnel) palsy",
     "question": "Weakness extending the fingers or thumb (finger drop) with preserved wrist extension? Deep aching localised more DISTAL than the epicondyle, in the muscle bellies of the proximal forearm, with tenderness over the radial tunnel between brachioradialis and extensor carpi radialis longus? Reproduced by resisted supination and resisted middle-finger extension? Progressive motor loss? NOTE: the posterior interosseous nerve runs under the ECRB fascia and supinator and can be entrapped there - PIN entrapment coexists in up to 15% of tennis-elbow cases; progressive weakness needs prompt evaluation, not just TrP treatment.",
     "source": "Tweedie & Vollans 2024; Buchanan & Varacallo 2023; Chung et al. 2025"
   },
   {
     "id": "rf-u2",
     "label": "Posterolateral rotatory instability",
     "question": "History of elbow dislocation, prior elbow surgery, or repeated steroid injections to the lateral elbow? Locking, catching, or a sensation of the elbow 'giving way' around 40 degrees of flexion? Positive table-top relocation or chair push-up apprehension test?",
     "source": "Chung et al. 2025"
   },
   {
     "id": "rf-u3",
     "label": "Osteochondritis dissecans of the capitellum",
     "question": "Is the patient a child or adolescent? Children and adolescents DO NOT get tennis elbow - lateral elbow pain in a skeletally immature patient is osteochondritis dissecans until proven otherwise, especially in throwers or gymnasts who load the elbow in extension. Pain on the active radiocapitellar compression test (pain on forearm rotation with the arm extended)? Mechanical catching or locking suggesting a loose body? Radiographs are mandatory in this group.",
     "source": "Tweedie & Vollans 2024 (age filter); Chung et al. 2025"
   },
   {
     "id": "rf-u4",
     "label": "Occult fracture / intra-articular loose body",
     "question": "Significant trauma or fall? Bony point tenderness over the radial head or lateral column, effusion, or a painful click at the end of supination/extension with the forearm supinated? Posterior radiocapitellar joint-line tenderness?",
     "source": "Chung et al. 2025"
   },
   {
     "id": "rf-u5",
     "label": "Cervical radiculopathy (C6-C7)",
     "question": "Neck pain with dermatomal arm/forearm pain? Positive Spurling's test? Objective sensory deficit, reflex change (brachioradialis C6, triceps C7), or myotomal weakness? Radicular pain not reproduced by local muscle palpation?",
     "source": "Chung et al. 2025; standard radiculopathy screen"
   }
 ],
 "broad_differential": [
   {
     "id": "bd-1",
     "condition": "Lateral epicondylitis (tennis elbow)",
     "confidence": "common",
     "mimics": "The single most common structural diagnosis at the lateral epicondyle - overlaps directly with the radial wrist extensor and finger extensor TrP referral",
     "distinguishing_feature": "Localised tenderness at the lateral epicondyle / common extensor origin, 1-2 cm distal to the ECRB attachment; positive Cozen's test (pain on resisted wrist extension) and resisted middle-finger extension. The pathognomonic sign (Briggs & Elliott): with the forearm fully pronated and the wrist flexed, extending the elbow produces severe pain over the last 20 degrees of extension as the radial head shears against the ECRB. Crucially, the epicondylar enthesopathy is frequently SECONDARY to taut-band tension from central TrPs in supinator, brachioradialis, the radial wrist extensors, and the finger extensors - compressing the responsible central TrP reproduces and abolishes the epicondylar pain. A degenerative tendinosis, not inflammation; a bursa underlies the ECRB in up to half of surgical cases.",
     "action": "Examine for the central TrP driving the enthesopathy before labelling it isolated epicondylitis. Conservative: load modification, counterforce strap, eccentric loading, TrP inactivation. PIN/radial tunnel entrapment coexists in up to 15% of cases. Surgery only after 6-12 months of failed conservative care; repeated steroid injections risk tendon rupture and fatty atrophy.",
     "source": "Briggs & Elliott 1985 (pathognomonic sign, bursa); Buchanan & Varacallo 2023; Chung et al. 2025"
   },
   {
     "id": "bd-2",
     "condition": "Radial tunnel syndrome (posterior interosseous nerve entrapment)",
     "confidence": "uncommon",
     "mimics": "Lateral forearm pain - overlaps the supinator TrP zone and is frequently confused with resistant tennis elbow",
     "distinguishing_feature": "Pain localised more DISTALLY than the epicondyle - over the muscle bellies arising from the common extensor origin, tender over the radial tunnel which is palpated between brachioradialis and extensor carpi radialis longus (the brachioradialis lifts on resisted isometric elbow flexion in mid-prone, marking the tunnel's radial border). Cozen's test often negative or only weakly positive; pain provoked by direct compression over the nerve and by resisted supination. Found in repetitive-task workers (musicians, rowers, factory work). The PIN runs under the ECRB fascia and supinator - the supinator's own taut bands can both mimic and cause this entrapment.",
     "action": "Distinguish from epicondylitis by the distal pain location, the radial-tunnel tenderness, and the provocation pattern. Inactivate supinator TrPs first; a diagnostic local-anaesthetic block around the radial nerve can confirm. If motor weakness or progressive symptoms, EMG/NCS and surgical decompression (release of ECRB fascia, crossing vessels, and supinator). Coexists in up to 15% of tennis-elbow cases.",
     "source": "Tweedie & Vollans 2024; Buchanan & Varacallo 2023; Chung et al. 2025"
   },
   {
     "id": "bd-3",
     "condition": "Posterolateral rotatory instability (PLRI)",
     "confidence": "uncommon",
     "mimics": "Lateral elbow pain with vague mechanical symptoms - can be mistaken for resistant tennis elbow",
     "distinguishing_feature": "History of dislocation, prior surgery, or repeated steroid injections; locking, catching, or 'giving way' around 40 degrees of flexion; positive table-top relocation and chair push-up apprehension tests; pivot-shift positive under anaesthesia. TrP pain has no instability or mechanical giving-way.",
     "action": "Apprehension testing; MRI for lateral collateral ligament complex. Orthopaedic referral - conservative management often fails and surgical reconstruction is the mainstay.",
     "source": "Chung et al. 2025"
   },
   {
     "id": "bd-4",
     "condition": "Osteochondritis dissecans of the capitellum",
     "confidence": "uncommon",
     "mimics": "Lateral elbow pain in young throwing athletes and gymnasts - same population as overuse extensor TrPs",
     "distinguishing_feature": "Adolescent male thrower/gymnast; positive active radiocapitellar compression test (pain on forearm rotation with the arm extended); irregular capitellar articular surface, cystic change, or loose body on plain film/MRI. TrP pain has no articular surface change.",
     "action": "Radiographs mandatory in the at-risk group; MRI/ultrasound for staging. Activity restriction and splinting if no loose body; surgery for displaced or detached fragments.",
     "source": "Chung et al. 2025"
   },
   {
     "id": "bd-5",
     "condition": "Synovial plica syndrome / intra-articular loose body",
     "confidence": "uncommon",
     "mimics": "Lateral elbow pain with clicking, snapping, or occasional locking - can overlap supinator and anconeus presentations",
     "distinguishing_feature": "Insidious clicking or snapping felt at the lateral elbow, sometimes with locking. A symptomatic plica is provoked by the flexion-pronation manoeuvre: the elbow is flexed, the forearm maximally pronated, then passively extended with pressure over the posterolateral radiocapitellar joint and a valgus force - positive when snapping/pain occurs at around 30 degrees off full extension. Synovial plicae are present in over 86% of normal elbows, so MRI is often normal and the diagnosis is largely clinical and by exclusion. A loose body gives a painful click at end-supination/extension with point tenderness posterior to the radiocapitellar joint. TrP pain has no joint-line click.",
     "action": "Radiograph to exclude degenerative change; dynamic ultrasound to assess the click. Rest, anti-inflammatories, activity modification first; arthroscopic excision/debridement of the symptomatic plica (usually posterolateral) if refractory - early arthroscopy is advocated to prevent secondary radiocapitellar chondromalacia from plica kissing lesions.",
     "source": "Tweedie & Vollans 2024; Chung et al. 2025"
   },
   {
     "id": "bd-6",
     "condition": "Cervical radiculopathy (C6-C7)",
     "confidence": "uncommon",
     "mimics": "Lateral forearm and dorsal-hand pain - overlaps the distal referral of the extensor sources",
     "distinguishing_feature": "Dermatomal sensory deficit, reflex change (brachioradialis C6, triceps C7), myotomal weakness, positive Spurling's. TrP referral produces no reflex change or true dermatomal deficit and IS reproduced by muscle palpation. TrPs commonly develop secondarily to radiculopathy and may coexist.",
     "action": "Spurling's test, neurological examination. MRI cervical spine and EMG/NCS if neurological signs. Treat coexisting TrPs concurrently - they may be the dominant pain source.",
     "source": "Chung et al. 2025; standard radiculopathy screen"
   },
   {
     "id": "bd-7",
     "condition": "Radiocapitellar joint osteoarthritis",
     "confidence": "uncommon",
     "mimics": "Resistant lateral elbow pain on forearm rotation - a NORMAL radiograph commonly leads to mislabelling as persistent lateral epicondylitis",
     "distinguishing_feature": "The grip-and-grind (loaded supination) test is strongly positive: with passive unloaded rotation 80% of force passes through the ulnohumeral joint and there may be no pain, but with a firm grip 80% transfers to the radiocapitellar joint, reproducing pain and crepitus. End-range pain at flexion/extension extremes (osteophytes) but a pain-free through-range (ulnohumeral joint spared). Tennis-elbow provocation may be mildly positive, misleadingly. Typically males in the 4th-5th decade in moderate-to-heavy manual work; carrying angle may increase as the lateral column shortens.",
     "action": "Grip-and-grind test; X-ray (may be normal early - do not let this exclude the diagnosis); CT/MRI for cartilage wear in the radiocapitellar and lateral ulnohumeral compartments. Surgical ladder from arthroscopic debridement/arthrolysis through radial head excision to radiocapitellar arthroplasty. TrPs are independently treatable and frequently coexist.",
     "source": "Tweedie & Vollans 2024 (grip-and-grind, demographics); Chung et al. 2025"
   },
   {
     "id": "bd-9",
     "condition": "Snapping annular ligament",
     "confidence": "rare",
     "mimics": "Anterolateral elbow snapping that can be mistaken for a supinator or mechanical TrP click",
     "distinguishing_feature": "An uncomfortable snap located anterolaterally, typically occurring when moving from extension to flexion (and reproducible by the patient), often after prior injury to the lateral ligament complex. The thickened or displaced annular ligament subluxes over the radial head. Static imaging is usually normal; dynamic ultrasound is diagnostic, showing the ligament snapping over the radial head. TrP pain produces no ligamentous snap over the radial head.",
     "action": "X-ray to confirm absence of deformity, then dynamic ultrasound. If symptomatic and refractory, arthroscopic partial division of the annular ligament to lengthen it usually resolves the snapping.",
     "source": "Tweedie & Vollans 2024"
   },
   {
     "id": "bd-8",
     "condition": "Finger / wrist extensor arthritis attributed in error",
     "confidence": "uncommon",
     "mimics": "PIP joint stiffness and dorsal hand pain from extensor digitorum TrPs are frequently mislabelled as finger arthritis",
     "distinguishing_feature": "True arthritis shows joint swelling, radiographic change, and morning stiffness over an hour. Extensor digitorum TrPs can produce PIP tenderness and stiffness with NO joint pathology - a taut band in the forearm extensor mass reproduces the joint pain and abolishes it on TrP inactivation.",
     "action": "Examine the forearm extensor mass for taut bands reproducing the finger pain before accepting an arthritis label. Treat the TrP; reassess the joint.",
     "source": "T&S Vol.1 Ch.35 (Extensor Digitorum)"
   }
 ]

}

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