DiagnosticTree/VolarFinger
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{
"model": "bayesian_lr_scoring",
"version": "1.0",
"region_label": "Volar Finger Pain",
"description": "Probabilistic scoring model for pain on the volar (palmar) surface of the fingers. Three local sources generate it at the hand: the flexores digitorum superficialis and profundus, whose trigger points refer through the full length of the corresponding finger and beyond the fingertip; the interossei, referring through the palm and the radial index finger; and the abductor digiti minimi along the ulnar border of the little finger. Three more distant muscles refer to the palm and fingers from the trunk - latissimus dorsi (ulnar palm and ring/little fingers), serratus anterior (medial arm to the palm and ring finger, with a respiratory component), and subclavius (radial thumb/index/middle with an elbow-and-wrist skip). Structural differential led by trigger finger (stenosing flexor tenosynovitis) and the can't-miss flexor suppurative tenosynovitis, with jersey finger, carpal tunnel syndrome, Dupuytren's disease, and metacarpophalangeal joint arthritis (Jeanmonod et al. 2024; Shehab & Mirabelli 2013; AFP Finger Injuries).",
"thresholds": {
"early_exit_posterior": 0.55,
"early_exit_gap": 0.18,
"pairwise_trigger": 0.15
},
"muscles": {
"flexores_digitorum": {
"label": "Flexor Digitorum Superficialis and Profundus",
"prior": 0.2,
"page": "Muscle:Hand_and_Finger_Flexors",
"key_trp_note": "The long finger flexors in the forearm refer pain through the full volar length of the finger each one moves, characteristically 'shooting beyond the fingertip' - the lightning-stroke quality typical of the finger flexors and felt on the palmar surface. Each finger is served fairly specifically, so the painful finger points to the responsible muscle band. Kellgren showed that injecting the flexor digitorum profundus produces pain felt at the metacarpophalangeal joint that is indistinguishable from true intra-articular pain - a key reason these trigger points are mistaken for finger-joint arthritis. Activated by gross gripping; the tendon of the flexor is the structure involved in trigger finger.",
"subtitle": "Pain felt along the whole PALMAR (front) length of one finger, often described as shooting out past the fingertip; brought on by sustained or forceful gripping; the deep flexor's pain can be felt as if it comes from the knuckle joint"
},
"interossei": {
"label": "Interossei",
"prior": 0.2,
"page": "Muscle:Interossei",
"key_trp_note": "The intrinsic muscles between the metacarpals. The first dorsal interosseous is the most commonly involved, referring to the radial side of the index finger and deeply through the dorsum and palm; the other interossei refer along the side of the finger each occupies and into the palm. Activated by sustained or repetitive pincer grasp. A finger end-joint node may guide to the trigger point. Together with the abductor digiti minimi these are the intrinsic-hand sources of palmar and finger pain, as distinct from the long-finger-flexor referral that shoots to the fingertip.",
"subtitle": "Pain down the side of a finger (most often the radial side of the index) and deep through the PALM; brought on by sustained fine pinch; a Heberden's-type end-joint node on the affected finger may be a guide"
},
"abductor_digiti_minimi": {
"label": "Abductor Digiti Minimi",
"prior": 0.2,
"page": "Muscle:Interossei",
"key_trp_note": "The hypothenar muscle along the ulnar border of the hand; refers pain to the ulnar border of the little finger and the adjacent edge of the palm. A discrete source of little-finger pain distinct from the interossei and from the referred ulnar patterns of the trunk muscles. Activated by gripping and by repetitive little-finger abduction. Examine with the interossei, with which it shares the intrinsic-hand overload mechanism.",
"subtitle": "Pain along the ULNAR (outer) border of the LITTLE finger and the edge of the palm beneath it; brought on by gripping and by spreading the little finger out repeatedly"
},
"latissimus_dorsi": {
"label": "Latissimus Dorsi",
"prior": 0.133333,
"page": "Muscle:Latissimus_Dorsi",
"key_trp_note": "Refers from the inferior scapular angle and mid-back down the posterior arm to the ulnar forearm and hand, reaching the ulnar palm and the ring and little fingers. The mid-thoracic ache is characteristically constant and unchanged by ordinary movement. One of the pseudo-thoracic-outlet muscles; suspect it when volar ulnar-finger pain is accompanied by a constant mid-back or posterior axillary-fold ache. Activated by sustained loaded reaching.",
"subtitle": "A constant MID-BACK ache that spills down the back of the arm to the ULNAR palm and the ring and little fingers; unchanged by ordinary movement; a member of the pseudo-thoracic-outlet group"
},
"serratus_anterior": {
"label": "Serratus Anterior",
"prior": 0.133333,
"page": "Muscle:Serratus_Anterior",
"key_trp_note": "A lateral chest-wall muscle whose essential pain is at the anterolateral midchest (and a separate interscapular patch), with spillover down the medial arm to the palm and ring finger - which is how it reaches this region. Its signature is respiratory: a 'stitch in the side' on running, air hunger, and the inability to finish a sentence without pausing for breath. Activated by fast/prolonged running, push-ups, severe coughing, and the characteristic torsional stress of wrenching the body around (forcefully turning a steering wheel without power steering). The trigger point sits in the midaxillary line over the fifth or sixth rib. Left-sided pain must not be called myofascial until cardiac disease has been excluded.",
"subtitle": "Pain on the SIDE of the chest (and a patch between the shoulder blades) that spills down the inner arm to the PALM and RING finger; a 'stitch in the side', shortness of breath, or 'can't take a deep breath without it hurting'; brought on by hard running or wrenching the body around"
},
"subclavius": {
"label": "Subclavius",
"prior": 0.133333,
"page": "Muscle:Subclavius",
"key_trp_note": "A small muscle beneath the clavicle whose referral runs down the radial side of the arm and forearm, characteristically SKIPPING the elbow and wrist, and reappears on the radial hand at the volar thumb, index, and middle fingers. Its shortening draws the clavicle toward the subclavian vessels, a vascular (reduced-radial-pulse) mechanism. Routinely overlooked because it is palpated through the pectoralis major, with which it is almost always co-active. The radial-finger counterpart to the ulnar trunk referrers in this region.",
"subtitle": "Front-of-shoulder pain running down the RADIAL arm and forearm, SKIPPING the elbow and wrist, reappearing on the palm side of the thumb, index, and middle fingers; may reduce the radial pulse; almost always with pectoralis major"
}
},
"questions": [
{
"id": "q_zone",
"text": "Where does the pain seem to come from?",
"sublabel": "The dominant origin of the whole pattern",
"type": "choice",
"answers": [
{
"id": "finger_palm",
"label": "The FINGER and PALM themselves (forearm/hand)",
"sublabel": "Local hand source",
"lr": {
"flexores_digitorum": 5.0,
"interossei": 5.0,
"abductor_digiti_minimi": 5.0,
"latissimus_dorsi": 0.4,
"serratus_anterior": 0.4,
"subclavius": 0.6
}
},
{
"id": "mid_back",
"label": "The MID-BACK or below the shoulder blade, wrapping down the arm",
"sublabel": "Posterior thorax source",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 0.4,
"abductor_digiti_minimi": 0.5,
"latissimus_dorsi": 7.0,
"serratus_anterior": 1.2,
"subclavius": 0.6
}
},
{
"id": "side_of_chest",
"label": "The SIDE of the CHEST (and maybe between the shoulder blades)",
"sublabel": "Lateral chest source",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 0.4,
"abductor_digiti_minimi": 0.4,
"latissimus_dorsi": 1.0,
"serratus_anterior": 7.0,
"subclavius": 0.6
}
},
{
"id": "front_shoulder_skip",
"label": "The FRONT of the shoulder, with a column down the arm that skips the elbow",
"sublabel": "Anterior shoulder, skip column",
"lr": {
"flexores_digitorum": 0.5,
"interossei": 0.5,
"abductor_digiti_minimi": 0.5,
"latissimus_dorsi": 0.8,
"serratus_anterior": 0.9,
"subclavius": 7.0
}
}
]
},
{
"id": "q_which_finger",
"text": "Which fingers carry the pain, on the palm side?",
"sublabel": "The fingers involved separate the local and referred sources",
"type": "choice",
"answers": [
{
"id": "single_to_tip",
"label": "ONE finger in particular, the pain running its whole length and past the tip",
"sublabel": "Single finger to the tip",
"lr": {
"flexores_digitorum": 6.5,
"interossei": 1.5,
"abductor_digiti_minimi": 1.0,
"latissimus_dorsi": 0.5,
"serratus_anterior": 0.5,
"subclavius": 0.7
}
},
{
"id": "radial_thumb_index_middle",
"label": "The THUMB, INDEX, or MIDDLE finger (radial side) / deep palm",
"sublabel": "Radial fingers / palm",
"lr": {
"flexores_digitorum": 1.2,
"interossei": 4.0,
"abductor_digiti_minimi": 0.5,
"latissimus_dorsi": 0.5,
"serratus_anterior": 0.8,
"subclavius": 3.5
}
},
{
"id": "little_finger_ulnar",
"label": "The LITTLE finger and its ULNAR border",
"sublabel": "Little finger / ulnar border",
"lr": {
"flexores_digitorum": 1.0,
"interossei": 1.2,
"abductor_digiti_minimi": 6.0,
"latissimus_dorsi": 2.0,
"serratus_anterior": 1.0,
"subclavius": 0.5
}
},
{
"id": "ring_little",
"label": "The RING and LITTLE fingers / ulnar palm broadly",
"sublabel": "Ring & little / ulnar palm",
"lr": {
"flexores_digitorum": 1.0,
"interossei": 1.0,
"abductor_digiti_minimi": 1.5,
"latissimus_dorsi": 3.5,
"serratus_anterior": 3.0,
"subclavius": 0.5
}
}
]
},
{
"id": "q_quality",
"text": "What is the pain like?",
"sublabel": "The character separates the long flexors, the hand intrinsics, and the distant referrers",
"type": "choice",
"answers": [
{
"id": "shoots_past_tip",
"label": "A line of pain shooting along the finger and beyond the fingertip",
"sublabel": "Shoots past the fingertip",
"lr": {
"flexores_digitorum": 6.5,
"interossei": 0.8,
"abductor_digiti_minimi": 0.8,
"latissimus_dorsi": 0.5,
"serratus_anterior": 0.5,
"subclavius": 0.7
}
},
{
"id": "deep_palm_side_finger",
"label": "A deep ache in the palm and down the side of the finger",
"sublabel": "Deep palm / side of finger",
"lr": {
"flexores_digitorum": 0.8,
"interossei": 4.5,
"abductor_digiti_minimi": 3.5,
"latissimus_dorsi": 0.6,
"serratus_anterior": 0.6,
"subclavius": 0.8
}
},
{
"id": "knuckle_joint",
"label": "As though it comes from the KNUCKLE joint at the base of the finger",
"sublabel": "Knuckle-joint quality",
"lr": {
"flexores_digitorum": 4.5,
"interossei": 2.0,
"abductor_digiti_minimi": 1.0,
"latissimus_dorsi": 0.5,
"serratus_anterior": 0.5,
"subclavius": 0.6
}
},
{
"id": "distant_ache",
"label": "A spillover from an ache that really lives in the trunk, arm, or chest",
"sublabel": "Referred from a distance",
"lr": {
"flexores_digitorum": 0.5,
"interossei": 0.5,
"abductor_digiti_minimi": 0.6,
"latissimus_dorsi": 4.0,
"serratus_anterior": 4.0,
"subclavius": 3.0
}
}
]
},
{
"id": "q_provocation",
"text": "Which activity most reliably brings on the pain?",
"sublabel": "Choose the single strongest aggravator",
"type": "choice",
"answers": [
{
"id": "gross_gripping",
"label": "Forceful or sustained whole-hand gripping (tools, carrying, climbing)",
"sublabel": "Gross gripping",
"lr": {
"flexores_digitorum": 6.0,
"interossei": 1.0,
"abductor_digiti_minimi": 2.0,
"latissimus_dorsi": 0.7,
"serratus_anterior": 0.7,
"subclavius": 0.7
}
},
{
"id": "fine_pinch",
"label": "Sustained fine pinch between thumb and finger (sewing, writing, small tools)",
"sublabel": "Fine pinch",
"lr": {
"flexores_digitorum": 1.2,
"interossei": 6.0,
"abductor_digiti_minimi": 2.0,
"latissimus_dorsi": 0.6,
"serratus_anterior": 0.6,
"subclavius": 0.7
}
},
{
"id": "loaded_reaching",
"label": "Sustained loaded reaching, pulling, or working overhead",
"sublabel": "Loaded reaching / pulling",
"lr": {
"flexores_digitorum": 0.7,
"interossei": 0.7,
"abductor_digiti_minimi": 0.7,
"latissimus_dorsi": 6.0,
"serratus_anterior": 1.5,
"subclavius": 1.2
}
},
{
"id": "running_cough_torsion",
"label": "Hard running, coughing, or wrenching the body around (turning a heavy steering wheel)",
"sublabel": "Running / cough / torsion",
"lr": {
"flexores_digitorum": 0.6,
"interossei": 0.6,
"abductor_digiti_minimi": 0.6,
"latissimus_dorsi": 0.9,
"serratus_anterior": 7.0,
"subclavius": 0.9
}
},
{
"id": "front_shoulder_reach",
"label": "Reaching forward / round-shouldered posture, with a column of pain down the radial arm",
"sublabel": "Anterior shoulder load",
"lr": {
"flexores_digitorum": 0.7,
"interossei": 0.7,
"abductor_digiti_minimi": 0.7,
"latissimus_dorsi": 0.9,
"serratus_anterior": 1.0,
"subclavius": 5.5
}
}
]
},
{
"id": "q_respiratory",
"text": "Is there a 'stitch in the side', breathlessness, or pain that is clearly worse on taking a deep breath?",
"sublabel": "Serratus anterior signature - a respiratory symptom complex (air hunger, can't finish a sentence) distinguishes it from the other referrers",
"type": "binary",
"answers": [
{
"id": "yes",
"label": "Yes - a stitch in the side, breathlessness, or pain on deep breathing",
"lr": {
"flexores_digitorum": 0.6,
"interossei": 0.6,
"abductor_digiti_minimi": 0.6,
"latissimus_dorsi": 0.8,
"serratus_anterior": 7.0,
"subclavius": 0.9
}
},
{
"id": "no",
"label": "No - breathing does not affect it",
"lr": {
"flexores_digitorum": 1.1,
"interossei": 1.1,
"abductor_digiti_minimi": 1.1,
"latissimus_dorsi": 1.05,
"serratus_anterior": 0.3,
"subclavius": 1.0
}
}
]
},
{
"id": "q_skip_radial",
"text": "Does the arm pain SKIP the elbow and wrist - present in the arm and again in the radial fingers (thumb, index, middle), but not at the elbow or wrist?",
"sublabel": "The radial skip pattern of the subclavius",
"type": "binary",
"answers": [
{
"id": "yes",
"label": "Yes - the elbow and wrist are spared while the arm and radial fingers hurt",
"lr": {
"flexores_digitorum": 0.7,
"interossei": 0.8,
"abductor_digiti_minimi": 0.7,
"latissimus_dorsi": 0.9,
"serratus_anterior": 1.0,
"subclavius": 7.0
}
},
{
"id": "no",
"label": "No - the pain includes the elbow or wrist, or stays in the hand",
"lr": {
"flexores_digitorum": 1.1,
"interossei": 1.05,
"abductor_digiti_minimi": 1.1,
"latissimus_dorsi": 1.0,
"serratus_anterior": 1.0,
"subclavius": 0.3
}
}
]
},
{
"id": "q_palpation",
"text": "Where does firm palpation most precisely reproduce the familiar finger/palm pain?",
"sublabel": "The reproducing tender point - the most specific localiser",
"type": "choice",
"answers": [
{
"id": "volar_forearm",
"label": "In the front of the forearm (the finger-flexor muscle bellies)",
"sublabel": "Finger flexors location",
"lr": {
"flexores_digitorum": 7.0,
"interossei": 0.5,
"abductor_digiti_minimi": 0.5,
"latissimus_dorsi": 0.4,
"serratus_anterior": 0.4,
"subclavius": 0.4
}
},
{
"id": "between_metacarpals",
"label": "Between the long bones on the back/palm of the hand (the web spaces)",
"sublabel": "Interossei location",
"lr": {
"flexores_digitorum": 0.5,
"interossei": 7.0,
"abductor_digiti_minimi": 1.0,
"latissimus_dorsi": 0.4,
"serratus_anterior": 0.4,
"subclavius": 0.4
}
},
{
"id": "hypothenar_border",
"label": "Along the fleshy ulnar edge of the palm below the little finger",
"sublabel": "Abductor digiti minimi location",
"lr": {
"flexores_digitorum": 0.5,
"interossei": 1.0,
"abductor_digiti_minimi": 7.0,
"latissimus_dorsi": 0.5,
"serratus_anterior": 0.4,
"subclavius": 0.4
}
},
{
"id": "posterior_axillary_fold",
"label": "In the back wall of the armpit / side of the back (latissimus dorsi)",
"sublabel": "Latissimus dorsi location",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 0.4,
"abductor_digiti_minimi": 0.5,
"latissimus_dorsi": 7.0,
"serratus_anterior": 0.8,
"subclavius": 0.5
}
},
{
"id": "midaxillary_ribs",
"label": "On the side of the chest over the ribs, in line with the armpit (midaxillary line)",
"sublabel": "Serratus anterior location",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 0.4,
"abductor_digiti_minimi": 0.4,
"latissimus_dorsi": 0.8,
"serratus_anterior": 7.0,
"subclavius": 0.5
}
},
{
"id": "beneath_clavicle",
"label": "Deep beneath the collarbone (through the chest muscle)",
"sublabel": "Subclavius location",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 0.4,
"abductor_digiti_minimi": 0.4,
"latissimus_dorsi": 0.6,
"serratus_anterior": 0.6,
"subclavius": 7.0
}
}
]
}
],
"pairwise": [
{
"id": "pw_flex_inter",
"pair": [
"flexores_digitorum",
"interossei"
],
"text": "Tiebreaker - Finger Flexors vs Interossei",
"question": "Does the pain shoot along the finger and PAST THE FINGERTIP from a forearm point (finger flexors), or sit DEEP IN THE PALM and the side of the finger from a tender point between the hand bones (interossei)?",
"sublabel": "Long forearm flexors vs intrinsic hand muscles",
"answers": [
{
"id": "flex",
"label": "Shoots past the fingertip, forearm tender point - finger flexors",
"lr": {
"flexores_digitorum": 6.0,
"interossei": 0.4
}
},
{
"id": "inter",
"label": "Deep palm / side of finger, web-space tender point - interossei",
"lr": {
"flexores_digitorum": 0.4,
"interossei": 6.0
}
}
]
},
{
"id": "pw_inter_adm",
"pair": [
"interossei",
"abductor_digiti_minimi"
],
"text": "Tiebreaker - Interossei vs Abductor Digiti Minimi",
"question": "Is the pain in the radial index / deep palm from the web spaces (interossei), or specifically along the ULNAR BORDER of the little finger and the edge of the palm (abductor digiti minimi)?",
"sublabel": "Both are intrinsic-hand sources",
"answers": [
{
"id": "inter",
"label": "Radial index / deep palm, web-space point - interossei",
"lr": {
"interossei": 5.5,
"abductor_digiti_minimi": 0.4
}
},
{
"id": "adm",
"label": "Ulnar border of the little finger, hypothenar edge - abductor digiti minimi",
"lr": {
"interossei": 0.4,
"abductor_digiti_minimi": 5.5
}
}
]
},
{
"id": "pw_latd_sant",
"pair": [
"latissimus_dorsi",
"serratus_anterior"
],
"text": "Tiebreaker - Latissimus Dorsi vs Serratus Anterior",
"question": "Is the source a constant MID-BACK / posterior axillary ache (latissimus), or a SIDE-OF-CHEST pain with a respiratory component - stitch in the side, breathlessness (serratus anterior)?",
"sublabel": "Two trunk referrers reaching the palm and ulnar fingers",
"answers": [
{
"id": "latd",
"label": "Constant mid-back / posterior axillary fold - latissimus dorsi",
"lr": {
"latissimus_dorsi": 5.5,
"serratus_anterior": 0.4
}
},
{
"id": "sant",
"label": "Side of chest with stitch/breathlessness - serratus anterior",
"lr": {
"latissimus_dorsi": 0.4,
"serratus_anterior": 5.5
}
}
]
},
{
"id": "pw_sant_subcl",
"pair": [
"serratus_anterior",
"subclavius"
],
"text": "Tiebreaker - Serratus Anterior vs Subclavius",
"question": "Is the pain a SIDE-OF-CHEST/respiratory pattern reaching the palm and ring finger (serratus anterior), or a RADIAL arm column that SKIPS the elbow and wrist to the thumb/index/middle (subclavius)?",
"sublabel": "Lateral chest respiratory source vs radial skip source",
"answers": [
{
"id": "sant",
"label": "Side of chest, stitch/breathlessness, palm & ring finger - serratus anterior",
"lr": {
"serratus_anterior": 5.5,
"subclavius": 0.4
}
},
{
"id": "subcl",
"label": "Radial arm skipping elbow & wrist to thumb/index/middle - subclavius",
"lr": {
"serratus_anterior": 0.4,
"subclavius": 5.5
}
}
]
},
{
"id": "pw_flex_adm",
"pair": [
"flexores_digitorum",
"abductor_digiti_minimi"
],
"text": "Tiebreaker - Finger Flexors vs Abductor Digiti Minimi",
"question": "When the little finger is involved, does the pain shoot its whole length to the tip from a FOREARM point (flexor), or stay along its ULNAR BORDER from a point on the edge of the palm (abductor digiti minimi)?",
"sublabel": "Both can produce little-finger pain",
"answers": [
{
"id": "flex",
"label": "Shoots to the tip, forearm point - finger flexors",
"lr": {
"flexores_digitorum": 5.5,
"abductor_digiti_minimi": 0.4
}
},
{
"id": "adm",
"label": "Ulnar border, hypothenar palm point - abductor digiti minimi",
"lr": {
"flexores_digitorum": 0.4,
"abductor_digiti_minimi": 5.5
}
}
]
}
],
"treatment_dag": {
"edges": [
{
"from": "flexores_digitorum",
"to": "interossei",
"type": "functional_unit",
"label": "The long finger flexors and the hand intrinsics share the gripping/pinching load; examine the forearm flexors and the intrinsic muscles together"
},
{
"from": "interossei",
"to": "abductor_digiti_minimi",
"type": "functional_unit",
"label": "Interossei and abductor digiti minimi are intrinsic-hand muscles overloaded together by sustained grip and pinch; treat in the same session"
},
{
"from": "serratus_anterior",
"to": "latissimus_dorsi",
"type": "functional_unit",
"label": "Serratus anterior and latissimus dorsi are functional antagonists for scapular movement; latissimus may be overloaded secondarily - examine both"
},
{
"from": "latissimus_dorsi",
"to": "flexores_digitorum",
"type": "secondary_load",
"label": "Trunk and shoulder-girdle referrers (latissimus, serratus anterior, subclavius) can refer to the palm and fingers; address them when local hand treatment gives incomplete relief"
},
{
"from": "subclavius",
"to": "flexores_digitorum",
"type": "secondary_load",
"label": "Subclavius is a deep residual radial source (co-active with pectoralis major); treat after the local hand 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": "Flexor (suppurative) tenosynovitis",
"question": "Surgical emergency. The four Kanavel signs: fusiform ('sausage') swelling of the whole finger, the finger held semi-flexed at rest, tenderness along the flexor tendon sheath into the palm, and severe pain on PASSIVE EXTENSION of the finger. Usually follows a penetrating injury or bite. Needs urgent hand-surgery referral, IV antibiotics, and drainage - infection tracks proximally along the volar sheath.",
"source": "Standard hand-infection emergency criteria (Kanavel)"
},
{
"id": "rf-e2",
"label": "Deep palmar space infection / septic joint / felon",
"question": "A hot, red, tensely swollen palm or finger pulp with throbbing pain and severe tenderness, fever, or systemic upset, after a puncture, bite, or wound? A felon (closed-pulp-space infection of the fingertip), deep palmar-space infection, or septic finger joint needs urgent drainage and antibiotics.",
"source": "Sanderson, Mohr & Abraham 2020; standard hand-infection screen"
}
],
"urgent": [
{
"id": "rf-u1",
"label": "Jersey finger (flexor digitorum profundus avulsion)",
"question": "After a forced extension of an actively flexed finger (grabbing a jersey, a fall while gripping): inability to actively flex the fingertip (distal interphalangeal joint) of an otherwise intact finger, with volar tenderness and sometimes a palpable retracted tendon stump (a lump) in the finger or palm? The ring finger is most often affected and the patient often feels a 'snap'. Repair is urgent - the tendon must be reattached within about 10 days, before it retracts into the palm and becomes ischaemic.",
"source": "Brukner & Khan, Clinical Sports Medicine 3E, Ch.19; AFP Finger Injuries"
},
{
"id": "rf-u2",
"label": "Flexor tendon laceration / closed rupture",
"question": "Loss of active finger flexion at one or both finger joints after a volar laceration or forceful injury, with a posture of the finger out of the normal resting cascade? Partial lacerations may still flex but are at risk of rupture. Volar tendon injuries need hand-surgery assessment.",
"source": "AFP Finger Injuries; Sanderson, Mohr & Abraham 2020"
},
{
"id": "rf-u3",
"label": "Volar plate injury / proximal interphalangeal fracture-dislocation",
"question": "After a hyperextension injury: pain, swelling, and tenderness on the palmar side of the middle (proximal interphalangeal) finger joint, with instability or a fracture involving the joint surface on radiographs? Volar plate avulsions and unstable PIP fracture-dislocations need splinting in the correct position and hand-surgery referral to avoid stiffness and deformity.",
"source": "Brukner & Khan, Clinical Sports Medicine 3E, Ch.19; AFP Finger Injuries"
},
{
"id": "rf-u4",
"label": "Carpal tunnel syndrome (median neuropathy) with motor signs",
"question": "Palmar numbness and tingling of the thumb, index, middle, and radial ring finger, worse at night and with sustained gripping, with thenar weakness or wasting or a positive Phalen/Tinel? Progressive median neuropathy with motor loss needs nerve conduction studies and timely decompression. The finger flexors share the median nerve's course (pronator/anterior interosseous overlap).",
"source": "Shehab & Mirabelli 2013; Hand and Finger Flexors (Ch.38)"
}
],
"broad_differential": [
{
"id": "bd-1",
"condition": "Trigger finger (stenosing flexor tenosynovitis)",
"confidence": "common",
"mimics": "Palmar finger pain with catching - overlaps the finger-flexor and the volar metacarpophalangeal referral directly",
"distinguishing_feature": "Painful catching, clicking, or locking of the finger during active flexion and extension, with a palpable tender NODULE at the A1 pulley over the metacarpal head on the palmar side (usually at the metacarpophalangeal joint; occasionally A2/A3). The fourth finger and thumb are most often affected; women in the fifth-sixth decades, and people with diabetes or rheumatoid arthritis, are predisposed. Trigger-point pain has no mechanical locking and no A1-pulley nodule, though the two coexist and a flexor trigger point can aggravate the triggering.",
"action": "Clinical diagnosis; ultrasound (pulley thickening) in doubtful cases. Activity modification and splinting, then corticosteroid injection (less effective in diabetes); surgical A1-pulley release for refractory locking. Treat coexisting finger-flexor trigger points. Note the recently described variant of insertional flexor tendinopathy causing triggering without A1-pulley pathology.",
"source": "Jeanmonod et al. 2024 (Trigger Finger StatPearls); Donati et al. 2024"
},
{
"id": "bd-2",
"condition": "Carpal tunnel syndrome / median neuropathy",
"confidence": "common",
"mimics": "Palmar thumb/index/middle pain and numbness - overlaps the finger-flexor and interosseous palmar referral",
"distinguishing_feature": "Palmar median-distribution paraesthesia (thumb, index, middle, radial ring finger), nocturnal symptoms, and positive Phalen and Tinel tests, with thenar weakness/wasting in advanced disease. Symptoms follow the median sensory territory and are relieved by shaking the hand. Trigger-point referral produces no fixed sensory deficit, no nocturnal paraesthesia, and is reproduced by muscle palpation - though forearm finger-flexor trigger points (and pronator-level median compression) can mimic and coexist with it.",
"action": "Phalen/Tinel, sensory testing, thenar assessment; nerve conduction studies confirm and grade it. Night splinting, activity modification, corticosteroid injection; decompression for motor loss. Treat coexisting forearm finger-flexor and pronator trigger points.",
"source": "Shehab & Mirabelli 2013; Hand and Finger Flexors (Ch.38)"
},
{
"id": "bd-3",
"condition": "Metacarpophalangeal / proximal interphalangeal joint osteoarthritis or synovitis",
"confidence": "common",
"mimics": "Pain felt at the base or middle joint of the finger - the flexor digitorum profundus refers pain indistinguishable from joint pain (Kellgren)",
"distinguishing_feature": "Joint-line tenderness, swelling, stiffness, and crepitus at the affected finger joint, with radiographic joint-space narrowing or osteophytes; inflammatory synovitis adds warmth, prolonged morning stiffness, and a symmetrical multi-joint pattern (consider rheumatoid arthritis). Kellgren showed that flexor digitorum profundus trigger-point injection produces pain felt at the metacarpophalangeal joint indistinguishable from intra-articular pain, so a trigger-point source must be examined before attributing the pain to the joint.",
"action": "Joint examination and radiographs; inflammatory markers and a rheumatological review where synovitis or a symmetrical polyarthritis is suspected. Treat the joint disease and any coexisting finger-flexor and interosseous trigger points, which may be the dominant pain source even when radiographic changes are present.",
"source": "Hand and Finger Flexors (Ch.38); Interossei (Ch.40)"
},
{
"id": "bd-4",
"condition": "Dupuytren's disease (palmar fascial contracture)",
"confidence": "uncommon",
"mimics": "A palmar nodule or cord at the finger base - can be mistaken for a flexor trigger point or trigger-finger nodule",
"distinguishing_feature": "A firm, painless palmar NODULE and longitudinal CORD in the palmar fascia (most often the ring and little fingers), progressing to a fixed flexion contracture of the metacarpophalangeal and proximal interphalangeal joints that the patient cannot passively straighten (positive tabletop test). The cord is in the fascia, not the tendon, and there is no triggering or catching. Trigger-point pain is not associated with a fixed contracture or a palpable fascial cord.",
"action": "Clinical diagnosis; track the contracture with the tabletop test and goniometry. Observation while mild; needle aponeurotomy, collagenase injection, or fasciectomy when contracture limits function. Distinguish the painless fascial cord from a painful flexor trigger point.",
"source": "Interossei (Ch.40) context; general hand-surgery knowledge; WikiMSK"
},
{
"id": "bd-5",
"condition": "Flexor tendon / pulley injury and jersey finger",
"confidence": "uncommon",
"mimics": "Volar finger pain and loss of flexion after injury - overlaps the finger-flexor referral with a structural lesion",
"distinguishing_feature": "Jersey finger is a flexor digitorum profundus avulsion (forced extension of an actively flexed finger - most often the ring finger), giving loss of active distal-joint flexion, a felt 'snap', and sometimes a retracted tendon stump palpable as a lump in the finger or palm. Closed pulley ruptures (notably A2/A4 in rock climbers) cause volar pain, bowstringing of the tendon, and loss of grip power; lumbrical tears are a related climbing overuse injury. Trigger-point pain has no loss of active flexion and no structural defect.",
"action": "Test active flexion at each finger joint individually; ultrasound or MRI for tendon retraction and pulley integrity. Prompt hand-surgery referral for tendon avulsion or significant pulley rupture - profundus avulsions are repaired within about 10 days, before the tendon scars and retracts into the palm.",
"source": "Brukner & Khan, Clinical Sports Medicine 3E, Ch.19 (incl. Schoffl, Schweizer on climber pulley/lumbrical injuries); AFP Finger Injuries"
},
{
"id": "bd-6",
"condition": "Digital flexor tendon ganglion / retinacular cyst",
"confidence": "uncommon",
"mimics": "A small tender palmar lump at the finger base with pain on gripping - can mimic a trigger-finger nodule or flexor trigger point",
"distinguishing_feature": "A small, firm, often tender cyst (retinacular ganglion) fixed to the flexor tendon sheath at the base of the finger on the palmar side, painful when gripping a hard object. It does not move with the tendon, has no triggering or locking, and transilluminates. Trigger-point tenderness is in the muscle belly and lacks a discrete fixed cystic lump.",
"action": "Clinical diagnosis; ultrasound confirms a cyst. Reassurance, aspiration, or excision if symptomatic. Distinguish from a trigger-finger nodule (which moves with the tendon and causes catching).",
"source": "Jeanmonod et al. 2024 (Trigger Finger StatPearls, differential)"
},
{
"id": "bd-7",
"condition": "C8-T1 cervical radiculopathy / thoracic outlet syndrome",
"confidence": "uncommon",
"mimics": "Palmar ulnar-finger pain and numbness referred from the neck or shoulder girdle - overlaps the latissimus and the ulnar palmar referral",
"distinguishing_feature": "Dermatomal C8-T1 sensory change including the MEDIAL FOREARM (above the wrist), reflex/motor change, and a positive Spurling's point to a root lesion; thoracic outlet syndrome adds positional/provocative findings and sometimes vascular signs. Trigger-point referral produces no objective deficit, spares the medial forearm, and is reproduced by muscle palpation - and the trunk referrers here (latissimus, serratus anterior) are themselves common myofascial mimics of these.",
"action": "Full neurological and upper-quarter examination; Spurling's and thoracic-outlet provocative tests; MRI cervical spine and electrodiagnostics where neurological signs are present. Treat coexisting latissimus, serratus anterior, subclavius, and scalene trigger points concurrently.",
"source": "Differential:ThoracicOutletSyndrome; Shehab & Mirabelli 2013"
},
{
"id": "bd-8",
"condition": "Cardiac / referred visceral pain (left-sided)",
"confidence": "rare",
"mimics": "Left medial-arm and palm pain accompanying chest discomfort - the serratus anterior and pectoral patterns can contribute to or mimic cardiac pain",
"distinguishing_feature": "Exertional or rest chest pressure radiating to the left medial arm and hand, with breathlessness, diaphoresis, or cardiac risk factors. Serratus anterior trigger points can contribute to the pain of myocardial infarction, and relief of chest-wall pain by trigger-point treatment does NOT exclude cardiac disease. Trigger-point pain is reproduced by chest-wall palpation and lacks exertional ECG change.",
"action": "When left-sided chest and medial-arm/palm pain are present, establish cardiac status independently (ECG, troponin, risk assessment) regardless of any response to trigger-point treatment. Treat the chest-wall trigger points only once cardiac disease is addressed.",
"source": "Serratus Anterior (Ch.46); T&S Ch.42"
}
]
}