DiagnosticTree/DorsalForearm
{
"model": "bayesian_lr_scoring",
"version": "1.0",
"region_label": "Dorsal Forearm Pain",
"description": "Probabilistic scoring model for dorsal forearm pain. Eight equal-prior sources: three triceps brachii trigger points (long head, medial head, and lateral head) that each reach the dorsal forearm by a different route, the radial wrist extensors (longus and brevis), and three proximal sources whose pain spills to the dorsal forearm - teres major, coracobrachialis, and scalenus minimus. Structural differential from Pedowitz & Toutounghi 1988, Calotta & Dellon 2022, LaStayo & Lee 2006, and Forman et al. 2005.",
"thresholds": {
"early_exit_posterior": 0.55,
"early_exit_gap": 0.18,
"pairwise_trigger": 0.15
},
"muscles": {
"triceps_long_head": {
"label": "Triceps Brachii (long head)",
"prior": 0.125,
"page": "Muscle:Triceps_Brachii",
"key_trp_note": "A two-joint head and a notorious diagnostic blind spot. Its referral runs up over the posterior arm to the back of the shoulder and down over the dorsal forearm while characteristically SKIPPING the elbow - posterior arm and forearm pain with no elbow component should raise suspicion. The trigger point lies deep and needs pincer palpation. Activated by sustained elbow-forward, unsupported postures. Latissimus dorsi and serratus posterior superior can drive it as satellites - examine them for lasting resolution.",
"subtitle": "Pain over the back of the upper arm and shoulder running DOWN the dorsal forearm but SKIPPING the elbow; brought on by long periods with the elbow held forward and unsupported (driving, deskwork, handwork)"
},
"triceps_medial_head": {
"label": "Triceps Brachii (medial head, lateral portion)",
"prior": 0.125,
"page": "Muscle:Triceps_Brachii",
"key_trp_note": "Lies in the lateral portion of the medial head, about 4-6 cm above the lateral epicondyle. Refers to the lateral epicondyle and onto the radial forearm - a common, overlooked contributor to lateral epicondyle pain. The tell is residual percussion tenderness of the posterior lateral epicondyle that persists after the supinator, biceps, and brachioradialis trigger points have been treated. Provoked by resisted elbow extension; passive elbow flexion also hurts.",
"subtitle": "Pain at the lateral epicondyle extending onto the RADIAL side of the forearm; the often-missed 'tennis elbow' component; worse on resisted elbow straightening (pushing)"
},
"triceps_lateral_head": {
"label": "Triceps Brachii (lateral head)",
"prior": 0.125,
"page": "Muscle:Triceps_Brachii",
"key_trp_note": "Sits at the lateral border of the lateral head, just above where the radial nerve exits the spiral groove, so its taut band can entrap the sensory fibres of the radial nerve. The signature is a DUAL presentation: aching referred to the ring and little fingers from the trigger point itself, combined with tingling/numbness over the dorsal forearm, wrist, and hand to the base of the middle finger from radial-nerve compression. Firm palpation along the lateral intermuscular septum provokes hand tingling. Responds poorly to stretch-and-spray; usually needs injection.",
"subtitle": "Pain over the back of the arm and dorsal forearm, sometimes the ring and little fingers, PLUS tingling or numbness over the dorsal forearm/wrist/hand to the base of the middle finger (radial-nerve irritation) - a dual pattern"
},
"teres_major": {
"label": "Teres Major",
"prior": 0.125,
"page": "Muscle:Teres_Major",
"key_trp_note": "An uncommonly involved muscle whose essential zone is the posterior deltoid; the dorsal forearm is only an occasional spillover, and it must NOT refer to the elbow or hand (that points elsewhere). The most consistent activator is driving with heavy or non-power-assisted steering. It does not freeze the shoulder but causes pain near the full range on reaching forward and up. Anatomically inseparable from latissimus dorsi - examine the two together.",
"subtitle": "Deep pain in the posterior shoulder (back of the deltoid) that only OCCASIONALLY spills to the dorsal forearm; worse reaching forward and up; classic history is driving a vehicle without power steering; does NOT reach the elbow or hand"
},
"ecrl": {
"label": "Extensor Carpi Radialis Longus",
"prior": 0.125,
"page": "Muscle:Extensor_Carpi_Radialis",
"key_trp_note": "The more proximal of the radial wrist extensor pair. Refers to the lateral epicondyle and along the dorsoradial forearm to the wrist and anatomical snuffbox. Provoked by resisted wrist extension and gripping. Examined and treated with the brevis as a pair, and a common residual contributor to lateral elbow pain after the triceps is cleared.",
"subtitle": "Pain at the lateral epicondyle and down the dorsoradial forearm to the wrist and snuffbox; worse on resisted wrist extension and gripping"
},
"ecrb": {
"label": "Extensor Carpi Radialis Brevis",
"prior": 0.125,
"page": "Muscle:Extensor_Carpi_Radialis",
"key_trp_note": "The principal dorsal hand referrer of the radial wrist extensor pair; its referral spreads broadly across the back of the hand rather than to one focal point, reached via the dorsal forearm. Provoked by resisted wrist extension and gripping; the common extensor origin enthesopathy is often secondary to its taut-band tension. Treat with the longus.",
"subtitle": "Pain down the dorsal forearm spreading BROADLY across the back of the hand; worse on resisted wrist extension and gripping"
},
"coracobrachialis": {
"label": "Coracobrachialis",
"prior": 0.125,
"page": "Muscle:Coracobrachialis",
"key_trp_note": "A deep anterior shoulder muscle and a residual, last-to-be-found source - discovered after anterior deltoid and biceps are cleared yet deep anterior shoulder pain persists. Its referral is a distinctive interrupted 'skip' column: anterior shoulder, posterior arm, dorsal forearm, and dorsum of the hand to the middle fingertip, sparing the elbow and wrist. The Back-rub Test (reaching behind the back) is painful and resolves with treatment.",
"subtitle": "Anterior shoulder pain with an interrupted column down the back of the arm and dorsal forearm to the back of the hand, SKIPPING the elbow and wrist, possibly to the middle fingertip; a deep residual source"
},
"scalenus_minimus": {
"label": "Scalenus Minimus",
"prior": 0.125,
"page": "Muscle:Scalene",
"key_trp_note": "An inconstant deep scalene muscle (part of the scalene complex). Scalene trigger points are a key driver of satellite trigger points throughout the extensor and triceps groups, so their referred pain reaches the dorsal forearm. The neck must always be examined when a dorsal-forearm extensor or triceps trigger point is found, since treating the arm without addressing a scalene driver leads to recurrence. May contribute to a thoracic-outlet-type picture.",
"subtitle": "Neck-origin pain spilling down the arm to the dorsal forearm; a key driver of satellite trigger points throughout the extensor group; examine the neck"
}
},
"questions": [
{
"id": "q_zone",
"text": "Where does the overall pain seem to come from?",
"sublabel": "Choose the dominant origin of the whole pattern",
"type": "choice",
"answers": [
{
"id": "posterior_arm_shoulder",
"label": "The BACK of the upper arm and shoulder, running down toward the forearm",
"sublabel": "Posterior arm / shoulder source",
"lr": {
"triceps_long_head": 6.0,
"triceps_medial_head": 2.0,
"triceps_lateral_head": 4.0,
"teres_major": 3.0,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 0.6,
"scalenus_minimus": 0.6
}
},
{
"id": "anterior_shoulder",
"label": "The FRONT of the shoulder, with a column running down the arm to the hand",
"sublabel": "Anterior shoulder source",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.6,
"teres_major": 0.8,
"ecrl": 0.4,
"ecrb": 0.4,
"coracobrachialis": 7.0,
"scalenus_minimus": 0.6
}
},
{
"id": "neck",
"label": "The NECK, spreading down the arm to the forearm",
"sublabel": "Neck source",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.6,
"teres_major": 0.6,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 0.6,
"scalenus_minimus": 7.5
}
},
{
"id": "local_forearm",
"label": "The FOREARM itself, around the elbow or just below it",
"sublabel": "Local forearm / elbow source",
"lr": {
"triceps_long_head": 1.0,
"triceps_medial_head": 3.5,
"triceps_lateral_head": 1.5,
"teres_major": 0.4,
"ecrl": 5.0,
"ecrb": 5.0,
"coracobrachialis": 0.5,
"scalenus_minimus": 0.6
}
}
]
},
{
"id": "q_provocation",
"text": "Which activity most reliably brings on the pain?",
"sublabel": "Choose the single strongest aggravator",
"type": "choice",
"answers": [
{
"id": "resisted_elbow_ext",
"label": "Pushing or straightening the elbow against resistance (press-ups, dips, pushing a heavy door)",
"sublabel": "Resisted elbow extension",
"lr": {
"triceps_long_head": 3.0,
"triceps_medial_head": 6.0,
"triceps_lateral_head": 5.0,
"teres_major": 0.6,
"ecrl": 0.6,
"ecrb": 0.6,
"coracobrachialis": 0.5,
"scalenus_minimus": 0.5
}
},
{
"id": "resisted_wrist_ext",
"label": "Cocking the wrist back or gripping (lifting with the palm down, backhand)",
"sublabel": "Resisted wrist extension / gripping",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 1.0,
"triceps_lateral_head": 0.8,
"teres_major": 0.5,
"ecrl": 6.5,
"ecrb": 6.5,
"coracobrachialis": 0.5,
"scalenus_minimus": 0.6
}
},
{
"id": "elbow_forward_posture",
"label": "Long periods with the elbow held forward and unsupported (driving, writing, deskwork, needlework)",
"sublabel": "Sustained elbow-forward posture",
"lr": {
"triceps_long_head": 7.0,
"triceps_medial_head": 0.8,
"triceps_lateral_head": 1.0,
"teres_major": 1.2,
"ecrl": 0.6,
"ecrb": 0.6,
"coracobrachialis": 0.8,
"scalenus_minimus": 0.7
}
},
{
"id": "reach_drive_steer",
"label": "Reaching forward/overhead, or turning a stiff steering wheel (heavy / non-power steering)",
"sublabel": "Shoulder reach / heavy steering",
"lr": {
"triceps_long_head": 0.7,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.6,
"teres_major": 7.0,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 3.0,
"scalenus_minimus": 0.7
}
},
{
"id": "reach_behind_back",
"label": "Reaching behind the back, or deep front-of-shoulder pain on lifting forward",
"sublabel": "Back-rub / anterior shoulder load",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.6,
"teres_major": 1.2,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 7.0,
"scalenus_minimus": 0.6
}
},
{
"id": "neck_breathing",
"label": "Neck movement, or after a respiratory illness / chronic cough",
"sublabel": "Neck / respiratory overload",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.6,
"teres_major": 0.6,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 0.6,
"scalenus_minimus": 7.0
}
}
]
},
{
"id": "q_distal",
"text": "Where does the pain travel below the elbow?",
"sublabel": "Direction of distal spread",
"type": "choice",
"answers": [
{
"id": "radial_forearm_snuffbox",
"label": "Down the RADIAL (thumb-side) forearm to the wrist and snuffbox",
"sublabel": "Dorsoradial forearm/wrist",
"lr": {
"triceps_long_head": 0.8,
"triceps_medial_head": 3.0,
"triceps_lateral_head": 0.8,
"teres_major": 0.5,
"ecrl": 6.0,
"ecrb": 1.5,
"coracobrachialis": 0.6,
"scalenus_minimus": 0.8
}
},
{
"id": "broad_back_of_hand",
"label": "Down the forearm and BROADLY across the back of the hand",
"sublabel": "Diffuse dorsal hand",
"lr": {
"triceps_long_head": 0.8,
"triceps_medial_head": 0.8,
"triceps_lateral_head": 1.0,
"teres_major": 0.5,
"ecrl": 1.5,
"ecrb": 6.5,
"coracobrachialis": 1.0,
"scalenus_minimus": 0.8
}
},
{
"id": "ring_little_fingers",
"label": "To the ring and little fingers",
"sublabel": "Ulnar fingers",
"lr": {
"triceps_long_head": 1.0,
"triceps_medial_head": 0.7,
"triceps_lateral_head": 5.5,
"teres_major": 0.6,
"ecrl": 0.7,
"ecrb": 0.8,
"coracobrachialis": 0.6,
"scalenus_minimus": 1.2
}
},
{
"id": "middle_fingertip_skip",
"label": "Out to the tip of the MIDDLE finger, with the column skipping the elbow and wrist",
"sublabel": "Middle fingertip, skip pattern",
"lr": {
"triceps_long_head": 1.5,
"triceps_medial_head": 0.6,
"triceps_lateral_head": 0.8,
"teres_major": 0.5,
"ecrl": 0.6,
"ecrb": 0.8,
"coracobrachialis": 6.5,
"scalenus_minimus": 0.8
}
},
{
"id": "no_distal",
"label": "It stays in the arm/forearm - no clear spread below into the hand",
"sublabel": "No distal hand spread",
"lr": {
"triceps_long_head": 1.5,
"triceps_medial_head": 1.2,
"triceps_lateral_head": 0.8,
"teres_major": 2.5,
"ecrl": 0.8,
"ecrb": 0.6,
"coracobrachialis": 0.6,
"scalenus_minimus": 1.0
}
}
]
},
{
"id": "q_radial_nerve",
"text": "Is there tingling or numbness over the dorsal forearm, wrist, and hand toward the base of the middle finger (as well as the aching pain)?",
"sublabel": "Radial-nerve irritation signature of the lateral head of triceps - a dual pain-plus-tingling pattern",
"type": "binary",
"answers": [
{
"id": "yes",
"label": "Yes - tingling/numbness in that dorsal distribution alongside the ache",
"lr": {
"triceps_long_head": 0.8,
"triceps_medial_head": 0.8,
"triceps_lateral_head": 7.0,
"teres_major": 0.6,
"ecrl": 0.8,
"ecrb": 0.8,
"coracobrachialis": 0.8,
"scalenus_minimus": 1.5
}
},
{
"id": "no",
"label": "No - aching pain only, no tingling or numbness",
"lr": {
"triceps_long_head": 1.1,
"triceps_medial_head": 1.1,
"triceps_lateral_head": 0.3,
"teres_major": 1.1,
"ecrl": 1.0,
"ecrb": 1.0,
"coracobrachialis": 1.0,
"scalenus_minimus": 1.0
}
}
]
},
{
"id": "q_elbow_skip",
"text": "Does the pain SKIP the elbow - present in the arm above and the forearm below, but not at the elbow itself?",
"sublabel": "The skip pattern of the long head of triceps and of coracobrachialis",
"type": "binary",
"answers": [
{
"id": "yes",
"label": "Yes - the elbow itself is spared while the arm and forearm hurt",
"lr": {
"triceps_long_head": 5.5,
"triceps_medial_head": 0.4,
"triceps_lateral_head": 1.2,
"teres_major": 1.0,
"ecrl": 0.5,
"ecrb": 0.6,
"coracobrachialis": 4.0,
"scalenus_minimus": 1.0
}
},
{
"id": "no",
"label": "No - the pain includes or centres on the elbow region",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 2.0,
"triceps_lateral_head": 1.0,
"teres_major": 0.9,
"ecrl": 1.5,
"ecrb": 1.2,
"coracobrachialis": 0.5,
"scalenus_minimus": 0.9
}
}
]
},
{
"id": "q_shoulder_pattern",
"text": "If there is a shoulder component, which fits best?",
"sublabel": "Posterior vs anterior shoulder source, vs none",
"type": "choice",
"answers": [
{
"id": "posterior_deltoid_driving",
"label": "Deep pain at the BACK of the shoulder (posterior deltoid), worse reaching forward/up or with heavy steering",
"sublabel": "Posterior deltoid - teres major",
"lr": {
"triceps_long_head": 1.5,
"triceps_medial_head": 0.6,
"triceps_lateral_head": 0.8,
"teres_major": 7.0,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 0.8,
"scalenus_minimus": 0.6
}
},
{
"id": "anterior_deep_skip",
"label": "Deep pain at the FRONT of the shoulder with the skipping column to the hand",
"sublabel": "Anterior shoulder - coracobrachialis",
"lr": {
"triceps_long_head": 0.7,
"triceps_medial_head": 0.5,
"triceps_lateral_head": 0.7,
"teres_major": 0.7,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 7.0,
"scalenus_minimus": 0.7
}
},
{
"id": "back_of_arm_shoulder",
"label": "Back of the shoulder and upper arm, blending into the posterior arm pain",
"sublabel": "Posterior arm - long head of triceps",
"lr": {
"triceps_long_head": 5.0,
"triceps_medial_head": 1.0,
"triceps_lateral_head": 2.5,
"teres_major": 1.5,
"ecrl": 0.6,
"ecrb": 0.6,
"coracobrachialis": 0.8,
"scalenus_minimus": 0.8
}
},
{
"id": "no_shoulder",
"label": "No shoulder component - pain is forearm/elbow only",
"sublabel": "No shoulder involvement",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 2.0,
"triceps_lateral_head": 1.0,
"teres_major": 0.3,
"ecrl": 2.5,
"ecrb": 2.5,
"coracobrachialis": 0.4,
"scalenus_minimus": 0.8
}
}
]
},
{
"id": "q_neck_driver",
"text": "Is there accompanying neck pain or tightness, or does pressing the side of the neck reproduce or worsen the arm pain?",
"sublabel": "Scalene driver screen - scalene trigger points seed satellite trigger points down the extensor group",
"type": "binary",
"answers": [
{
"id": "yes",
"label": "Yes - neck pain/tightness, or neck pressure reproduces the arm pain",
"lr": {
"triceps_long_head": 0.8,
"triceps_medial_head": 0.7,
"triceps_lateral_head": 0.9,
"teres_major": 0.8,
"ecrl": 0.7,
"ecrb": 0.7,
"coracobrachialis": 0.8,
"scalenus_minimus": 6.5
}
},
{
"id": "no",
"label": "No - no neck component",
"lr": {
"triceps_long_head": 1.1,
"triceps_medial_head": 1.1,
"triceps_lateral_head": 1.0,
"teres_major": 1.1,
"ecrl": 1.1,
"ecrb": 1.1,
"coracobrachialis": 1.1,
"scalenus_minimus": 0.3
}
}
]
},
{
"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": "long_head_pincer",
"label": "Deep in the back of the upper arm, lifting the long head off the bone with a pincer grip",
"sublabel": "Long head of triceps location",
"lr": {
"triceps_long_head": 7.0,
"triceps_medial_head": 0.6,
"triceps_lateral_head": 0.8,
"teres_major": 0.6,
"ecrl": 0.4,
"ecrb": 0.4,
"coracobrachialis": 0.4,
"scalenus_minimus": 0.4
}
},
{
"id": "above_lateral_epicondyle",
"label": "In the distal arm 4-6 cm above the lateral epicondyle (lateral border of the medial head)",
"sublabel": "Medial head (lateral portion) location",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 7.0,
"triceps_lateral_head": 1.2,
"teres_major": 0.5,
"ecrl": 0.8,
"ecrb": 0.6,
"coracobrachialis": 0.4,
"scalenus_minimus": 0.4
}
},
{
"id": "lateral_head_radial_nerve",
"label": "At the lateral border of the lateral head, where pressing provokes tingling into the hand",
"sublabel": "Lateral head location (over the radial nerve)",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 1.0,
"triceps_lateral_head": 7.0,
"teres_major": 0.5,
"ecrl": 0.5,
"ecrb": 0.5,
"coracobrachialis": 0.4,
"scalenus_minimus": 0.4
}
},
{
"id": "posterior_axillary_fold",
"label": "In the posterior axillary fold (the deeper muscle within it)",
"sublabel": "Teres major location",
"lr": {
"triceps_long_head": 0.6,
"triceps_medial_head": 0.4,
"triceps_lateral_head": 0.5,
"teres_major": 7.0,
"ecrl": 0.4,
"ecrb": 0.4,
"coracobrachialis": 0.5,
"scalenus_minimus": 0.4
}
},
{
"id": "radial_extensor_mass",
"label": "Just below the elbow crease in the radial wrist-extensor mass (ulnar to brachioradialis)",
"sublabel": "Radial wrist extensor location (longus/brevis)",
"lr": {
"triceps_long_head": 0.5,
"triceps_medial_head": 0.8,
"triceps_lateral_head": 0.5,
"teres_major": 0.4,
"ecrl": 6.5,
"ecrb": 6.5,
"coracobrachialis": 0.4,
"scalenus_minimus": 0.4
}
},
{
"id": "deep_anterior_shoulder",
"label": "Deep in the front of the shoulder, beneath the deltoid (deeper than the deltoid)",
"sublabel": "Coracobrachialis location",
"lr": {
"triceps_long_head": 0.5,
"triceps_medial_head": 0.4,
"triceps_lateral_head": 0.5,
"teres_major": 0.7,
"ecrl": 0.4,
"ecrb": 0.4,
"coracobrachialis": 7.0,
"scalenus_minimus": 0.5
}
},
{
"id": "side_of_neck",
"label": "In the side of the neck (scalene muscles)",
"sublabel": "Scalenus minimus location",
"lr": {
"triceps_long_head": 0.5,
"triceps_medial_head": 0.4,
"triceps_lateral_head": 0.5,
"teres_major": 0.5,
"ecrl": 0.4,
"ecrb": 0.4,
"coracobrachialis": 0.5,
"scalenus_minimus": 7.5
}
}
]
}
],
"pairwise": [
{
"id": "pw_tlh_tlat",
"pair": [
"triceps_long_head",
"triceps_lateral_head"
],
"text": "Tiebreaker - Triceps long head vs lateral head",
"question": "Is there tingling/numbness toward the base of the middle finger (radial-nerve irritation), or is it aching pain that skips the elbow with no tingling?",
"sublabel": "Lateral head irritates the radial nerve; long head gives the elbow-skipping ache",
"answers": [
{
"id": "tingling",
"label": "Tingling/numbness to the middle-finger base - lateral head",
"lr": {
"triceps_long_head": 0.3,
"triceps_lateral_head": 6.0
}
},
{
"id": "skip_ache",
"label": "Aching that skips the elbow, no tingling - long head",
"lr": {
"triceps_long_head": 6.0,
"triceps_lateral_head": 0.3
}
}
]
},
{
"id": "pw_tmh_ecrl",
"pair": [
"triceps_medial_head",
"ecrl"
],
"text": "Tiebreaker - Triceps medial head vs Extensor Carpi Radialis Longus",
"question": "Is the lateral epicondyle pain reproduced by resisted ELBOW extension (pushing), or by resisted WRIST extension and gripping?",
"sublabel": "Triceps source (elbow extensor) vs radial wrist extensor source",
"answers": [
{
"id": "elbow",
"label": "Resisted elbow extension - triceps medial head",
"lr": {
"triceps_medial_head": 6.0,
"ecrl": 0.3
}
},
{
"id": "wrist",
"label": "Resisted wrist extension / gripping - extensor carpi radialis longus",
"lr": {
"triceps_medial_head": 0.3,
"ecrl": 6.0
}
}
]
},
{
"id": "pw_ecrl_ecrb",
"pair": [
"ecrl",
"ecrb"
],
"text": "Tiebreaker - Extensor Carpi Radialis Longus vs Brevis",
"question": "Is the distal pain focal toward the dorsoradial wrist and snuffbox, or spread BROADLY across the back of the hand?",
"sublabel": "Longus refers more to the dorsoradial wrist; brevis broadly across the hand",
"answers": [
{
"id": "dorsoradial",
"label": "Focal dorsoradial wrist / snuffbox - longus",
"lr": {
"ecrl": 5.0,
"ecrb": 0.4
}
},
{
"id": "broad",
"label": "Broadly across the back of the hand - brevis",
"lr": {
"ecrl": 0.4,
"ecrb": 5.0
}
}
]
},
{
"id": "pw_tlh_cb",
"pair": [
"triceps_long_head",
"coracobrachialis"
],
"text": "Tiebreaker - Triceps long head vs Coracobrachialis",
"question": "Does the pain start at the BACK of the shoulder/posterior arm, or at the FRONT of the shoulder with a column to the middle fingertip?",
"sublabel": "Both can skip the elbow - separate them by the shoulder end of the pattern",
"answers": [
{
"id": "posterior",
"label": "Back of the shoulder / posterior arm - long head of triceps",
"lr": {
"triceps_long_head": 6.0,
"coracobrachialis": 0.3
}
},
{
"id": "anterior",
"label": "Front of the shoulder, column to the middle fingertip - coracobrachialis",
"lr": {
"triceps_long_head": 0.3,
"coracobrachialis": 6.0
}
}
]
},
{
"id": "pw_tm_cb",
"pair": [
"teres_major",
"coracobrachialis"
],
"text": "Tiebreaker - Teres Major vs Coracobrachialis",
"question": "Is the shoulder pain at the BACK (posterior deltoid, worse with heavy steering), or deep at the FRONT (with the skipping column to the hand)?",
"sublabel": "Posterior deltoid source vs deep anterior shoulder source",
"answers": [
{
"id": "posterior",
"label": "Posterior deltoid, heavy-steering history - teres major",
"lr": {
"teres_major": 6.0,
"coracobrachialis": 0.3
}
},
{
"id": "anterior",
"label": "Deep anterior shoulder, skip column - coracobrachialis",
"lr": {
"teres_major": 0.3,
"coracobrachialis": 6.0
}
}
]
}
],
"treatment_dag": {
"edges": [
{
"from": "scalenus_minimus",
"to": "triceps_long_head",
"type": "key_satellite",
"label": "Scalene trigger points seed satellite triceps trigger points; treat the neck first"
},
{
"from": "scalenus_minimus",
"to": "ecrb",
"type": "key_satellite",
"label": "Scalene trigger points seed satellite extensor trigger points; address the neck driver"
},
{
"from": "triceps_long_head",
"to": "triceps_medial_head",
"type": "functional_unit",
"label": "Triceps heads act together in elbow extension; examine all heads"
},
{
"from": "triceps_long_head",
"to": "triceps_lateral_head",
"type": "functional_unit",
"label": "Triceps heads act together; the lateral head additionally risks radial-nerve irritation"
},
{
"from": "ecrl",
"to": "ecrb",
"type": "functional_unit",
"label": "Radial wrist extensor pair - examine and treat together"
},
{
"from": "teres_major",
"to": "triceps_long_head",
"type": "secondary_load",
"label": "Teres major and the long head share a myotatic unit; teres major can drive the long head"
},
{
"from": "triceps_lateral_head",
"to": "ecrl",
"type": "secondary_load",
"label": "If lateral elbow pain persists after the triceps, examine the radial wrist extensors"
},
{
"from": "coracobrachialis",
"to": "triceps_long_head",
"type": "secondary_load",
"label": "Coracobrachialis is a deep residual anterior-shoulder source; treat after the primary muscles"
}
],
"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 or elevation? Pain sharply increased by passive finger or wrist movement? Tense or woody forearm? Paraesthesia, pallor, or weakness of the hand? Recent fracture, crush, tight cast, or circumferential burn?",
"source": "Pedowitz & Toutounghi 1988; standard limb emergency screen"
},
{
"id": "rf-e2",
"label": "Septic arthritis of the elbow / forearm joints",
"question": "Acutely hot, swollen, exquisitely tender elbow or wrist 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": "Chronic exertional compartment syndrome of the forearm",
"question": "Effort-related forearm aching and swelling that builds with sustained, strenuous activity (manual work, gripping sport) and eases with rest, sometimes with paraesthesia of the ulnar or median distribution? Forearm fullness after exercise? Often misattributed to epicondylitis. Intramuscular pressure studies confirm; decompressive fasciotomy is the treatment.",
"source": "Pedowitz & Toutounghi 1988"
},
{
"id": "rf-u2",
"label": "Forearm fracture or fracture-dislocation (Monteggia, Galeazzi, Essex-Lopresti)",
"question": "Significant trauma, fall, or axial load to the forearm? Bony tenderness, deformity, or a painful, limited, or 'popping' forearm rotation after an apparent isolated fracture? NOTE: when one forearm bone is fractured, suspect a dislocation of the other - a radial head fracture with wrist pain suggests Essex-Lopresti (interosseous membrane disruption); an ulnar fracture with radial head dislocation is a Monteggia injury; a radial shaft fracture with distal radioulnar joint dislocation is a Galeazzi injury.",
"source": "LaStayo & Lee 2006"
},
{
"id": "rf-u3",
"label": "Radial sensory nerve / posterior interosseous nerve entrapment",
"question": "Burning or electric dorsoradial forearm and wrist pain with paraesthesia, worsened by ulnar wrist flexion (Wartenberg's), or progressive weakness of finger/thumb extension (posterior interosseous nerve)? A positive Tinel sign over the radial sensory nerve as it emerges between brachioradialis and the radial wrist extensor? Distinguish neuropathic pain and any motor loss from a myofascial source.",
"source": "Calotta & Dellon 2022; Forman et al. 2005"
},
{
"id": "rf-u4",
"label": "Cervical radiculopathy (C6-C8) / thoracic outlet syndrome",
"question": "Neck pain with dermatomal forearm/hand pain, sensory deficit, reflex change, or myotomal weakness? Positive Spurling's test? Or ulnar-sided symptoms with positive EAST/Roos and a vascular component? A proximal driver must be excluded - and scalene trigger points frequently coexist with and drive a thoracic-outlet picture.",
"source": "Forman et al. 2005; standard radiculopathy screen"
}
],
"broad_differential": [
{
"id": "bd-1",
"condition": "Chronic exertional compartment syndrome of the forearm",
"confidence": "uncommon",
"mimics": "Effort-related dorsal/volar forearm aching and swelling in manual workers and gripping athletes - overlaps the overuse history and forearm location of the extensor and triceps trigger points",
"distinguishing_feature": "Forearm aching, fullness, and sometimes paraesthesia that build predictably with sustained strenuous activity and resolve with rest, often initially misdiagnosed as epicondylitis. Volumetric forearm swelling with exercise; elevated resting and post-exercise intramuscular pressures are diagnostic (e.g. post-exercise pressure at or above 25 mmHg). Trigger-point pain is reproduced by muscle palpation and is not pressure-dependent on exertion.",
"action": "Intramuscular (slit/wick catheter) pressure measurement before and after exercise confirms the diagnosis; MRI may show post-exercise fascial-plane obscuration. Decompressive fasciotomy is effective when conservative measures fail. Maintain a high index of suspicion - the upper-limb form is rare and frequently diagnosed late.",
"source": "Pedowitz & Toutounghi 1988"
},
{
"id": "bd-2",
"condition": "Radial sensory nerve pain (Wartenberg's syndrome / cheiralgia paraesthetica)",
"confidence": "uncommon",
"mimics": "Dorsoradial forearm and wrist pain - overlaps the radial wrist extensor and lateral-head triceps referral and is on the same nerve's course",
"distinguishing_feature": "Burning or electric pain with paraesthesia/numbness over the dorsoradial forearm, wrist, and thumb-index web, worsened by ulnar wrist flexion (which tightens the nerve where it emerges between the brachioradialis and the radial wrist extensor) and by tight watch straps; positive Tinel sign over the nerve. In up to 75% of people the lateral antebrachial cutaneous nerve overlaps the radial sensory territory, so a residual painful area after a radial-nerve block points to that second nerve. Trigger-point pain produces aching without objective sensory loss.",
"action": "Differential diagnostic nerve blocks (radial sensory nerve, then lateral antebrachial cutaneous nerve) localise the generator. Remove external compression, activity modification, neural gliding; for refractory neuroma pain, neuroma resection with muscular implantation of BOTH involved nerves gives the best results (resecting the radial sensory nerve alone commonly fails).",
"source": "Calotta & Dellon 2022"
},
{
"id": "bd-3",
"condition": "Posterior interosseous nerve / radial tunnel syndrome",
"confidence": "uncommon",
"mimics": "Deep dorsoradial proximal-forearm pain - overlaps the medial-head and lateral-head triceps and radial wrist extensor zones",
"distinguishing_feature": "Aching localised to the extensor muscle bellies more distal than the lateral epicondyle, reproduced by resisted supination and resisted middle-finger extension; weakness of finger/thumb extension with preserved wrist extension indicates posterior interosseous nerve motor involvement. The lateral head of triceps can itself irritate the radial nerve proximally - distinguish the level by where the Tinel sign and tenderness localise.",
"action": "Clinical localisation; EMG/NCS for motor involvement; imaging for a compressive ganglion or mass. Activity modification and trigger-point treatment first; surgical decompression for progressive motor loss.",
"source": "Calotta & Dellon 2022; Forman et al. 2005"
},
{
"id": "bd-4",
"condition": "Radial head fracture / Essex-Lopresti injury",
"confidence": "uncommon",
"mimics": "Lateral and dorsal proximal-forearm pain after a fall - overlaps the proximal extensor and triceps zones",
"distinguishing_feature": "Radial head tenderness and painful, limited forearm rotation after a fall on the outstretched hand. Crucially, a radial head fracture accompanied by ULNAR-SIDED WRIST pain and proximal migration of the radius signals an Essex-Lopresti injury (interosseous membrane disruption) - the wrist pain is easily overlooked and changes management entirely. Trigger-point pain has no bony tenderness or rotation block.",
"action": "Radiographs of the elbow AND wrist; assess ulnar variance and distal radioulnar joint. CT/MRI for the interosseous membrane if Essex-Lopresti is suspected. Orthopaedic referral - radial head reconstruction is preferred over excision to prevent proximal migration and wrist pain.",
"source": "LaStayo & Lee 2006"
},
{
"id": "bd-5",
"condition": "Monteggia / Galeazzi fracture-dislocation",
"confidence": "rare",
"mimics": "Forearm pain with limited rotation after trauma - the muscular pain pattern can distract from an unreduced joint",
"distinguishing_feature": "A proximal ulnar fracture with radial head dislocation (Monteggia) or a radial shaft fracture with distal radioulnar joint dislocation (Galeazzi). The dislocation is missed if only the obvious fracture is treated; recurrent painful, limited forearm rotation after fixation of a single bone is the warning. Trigger-point pain follows no fracture history.",
"action": "Radiographs that include BOTH the elbow and wrist with any single-bone forearm fracture; restore length and alignment of the fractured bone surgically so the dislocation reduces and the annular ligament/soft tissues heal. Monitor for recurrent radial head subluxation.",
"source": "LaStayo & Lee 2006"
},
{
"id": "bd-6",
"condition": "Lateral epicondylitis (tennis elbow)",
"confidence": "common",
"mimics": "Lateral elbow and proximal dorsoradial forearm pain - overlaps the medial-head triceps and radial wrist extensor referral directly",
"distinguishing_feature": "Localised tenderness at the common extensor origin 1-2 cm distal to the lateral epicondyle; pain on resisted wrist extension (Cozen's) and resisted middle-finger extension. The enthesopathy is frequently secondary to taut-band tension in the radial wrist extensors; residual posterior-epicondyle percussion tenderness after the forearm extensors are treated instead implicates the medial head of triceps.",
"action": "Examine for the central trigger point driving the enthesopathy before labelling it isolated epicondylitis. Load modification, counterforce strap, eccentric loading, trigger-point release; surgery only after prolonged failed conservative care.",
"source": "Forman et al. 2005; LaStayo & Lee 2006"
},
{
"id": "bd-7",
"condition": "Cervical radiculopathy (C7) / thoracic outlet syndrome",
"confidence": "uncommon",
"mimics": "Posterior arm and dorsal forearm pain referred from the neck - overlaps the triceps (C7) referral and the scalene spillover",
"distinguishing_feature": "C7 radiculopathy gives dermatomal pain to the middle finger with possible triceps weakness and a diminished triceps reflex; positive Spurling's. Thoracic outlet syndrome gives ulnar-sided symptoms with positive EAST/Roos and sometimes vascular signs. Trigger-point referral produces no reflex change or true dermatomal deficit and IS reproduced by muscle palpation - and triceps/scalene trigger points are themselves commonly mistaken for C7 radiculopathy.",
"action": "Full neurological and upper-quarter examination; Spurling, EAST. MRI cervical spine and EMG/NCS if neurological signs. Treat coexisting scalene and triceps trigger points concurrently - they may be the dominant or driving source.",
"source": "Forman et al. 2005"
},
{
"id": "bd-8",
"condition": "Systemic and inflammatory causes (RA, gout/CPPD, peripheral neuropathy)",
"confidence": "uncommon",
"mimics": "Diffuse or multi-site forearm and wrist pain - can be mislabelled as regional overuse",
"distinguishing_feature": "Inflammatory arthritis (the wrist is the most common joint in RA) gives swelling, morning stiffness over an hour, and multi-joint involvement; crystal arthritis gives acute hot swollen joints; diabetic or other peripheral neuropathy gives glove-distribution sensory change. Trigger-point pain is focal, mechanically reproduced, and lacks systemic features - but a thorough review of systems is essential, as the wrist/forearm can be the first site of systemic disease.",
"action": "Review of systems and inflammatory/metabolic screen where suggested (ESR/CRP, urate, rheumatoid serology, glucose/HbA1c); rheumatology or internal-medicine referral as indicated. Treat coexisting trigger points concurrently.",
"source": "Forman et al. 2005"
}
]
}