DiagnosticTree/BackofHead
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{
"tree_id": "back-of-head-pain", "region": "Back-of-Head Pain", "start": "agg-1",
"redflags": {
"emergency": [
{
"id": "rf-e1",
"label": "Thunderclap headache",
"question": "Did the occipital or back-of-head pain reach maximum intensity within seconds to a minute — described as the worst headache of the patient's life?",
"rationale": "Subarachnoid haemorrhage classically presents as sudden-onset severe occipital headache. Any instantaneous-onset severe headache is an emergency until proven otherwise.",
"action": "Call emergency services immediately. Do not proceed with musculoskeletal assessment."
},
{
"id": "rf-e2",
"label": "Meningism",
"question": "Is there neck stiffness (true resistance to passive flexion, not just pain) with fever, photophobia, or non-blanching rash?",
"rationale": "Meningitis presents with occipital pain and true neck stiffness. Distinguish true meningism (resistance to passive flexion) from myofascial restricted range.",
"action": "Call emergency services immediately."
},
{
"id": "rf-e3",
"label": "Cerebellar or posterior fossa signs",
"question": "Is there ataxia, nystagmus, dysarthria, or diplopia alongside the occipital head pain?",
"rationale": "Posterior fossa lesions (cerebellar haemorrhage, posterior fossa tumour, Arnold-Chiari) can present as occipital pain. Neurological signs in this distribution are a red flag.",
"action": "Emergency medical referral. CT or MRI urgently required."
}
],
"urgent": [
{
"id": "rf-u1",
"label": "Temporal arteritis",
"question": "Is the patient aged 50+ with jaw claudication (pain building during chewing then easing at rest), scalp tenderness, or a non-pulsatile tender temporal or occipital artery?",
"rationale": "Temporal arteritis can affect the occipital arteries as well as temporal. Jaw claudication is pathognomonic. Same-day ESR required.",
"action": "Same-day GP referral + ESR and CRP. Do not delay for musculoskeletal assessment."
},
{
"id": "rf-u2",
"label": "Cervical instability",
"question": "Is there a history of significant trauma to the head or neck combined with arm symptoms, gait disturbance, or occipital pain worsened by neck loading?",
"rationale": "Odontoid fracture or cervical instability can refer pain to the occiput. Manual therapy and cervical stretch are contraindicated until cleared.",
"action": "Urgent spinal assessment — no manual therapy or cervical stretch until cleared."
},
{
"id": "rf-u3",
"label": "Progressive or new-onset occipital headache over 50",
"question": "Is this a new or changed occipital headache pattern in a patient over 50, particularly if worsening over weeks?",
"rationale": "New occipital headache in older patients warrants exclusion of posterior fossa pathology, intracranial hypertension, and temporal arteritis before myofascial assessment.",
"action": "Urgent GP or neurology referral for imaging."
}
]
},
"nodes": {
"agg-1": {
"type": "choice",
"question": "What is the PRIMARY circumstance or activity associated with the back-of-head pain?",
"clinical_rationale": "The ten muscles contributing to back-of-head pain separate cleanly into three mechanism groups. Jaw activity (chewing, clenching, bruxism) points to temporalis CTrP₄ or posterior digastric belly. Neck, shoulder, or postural loading covers the large group of posterior cervical, trapezius, and SCM muscles. Pain or aggravation specifically with head resting on a pillow at night — or a through-the-skull quality — points to the occipitalis. This first split avoids any premature commitment and routes efficiently to the correct examination pathway.",
"options": [
{
"label": "Jaw activity — chewing, clenching, or bruxism aggravates the back-of-head or posterior temporal pain",
"sublabel": "Jaw use reproduces or worsens the pain; may also have throat discomfort or swallowing symptoms",
"next": "jaw-throat-split-1"
},
{
"label": "Neck movement, sustained posture, or shoulder loading aggravates",
"sublabel": "Rotation, flexion, carrying weight, sustained desk work, or sleeping position worsens the occipital pain",
"next": "autonomic-split-1"
},
{
"label": "Pain is worst at night when resting the head on a pillow — or described as penetrating through the skull toward the eye",
"sublabel": "Cannot bear the weight of the back of the head on a pillow; OR pain feels deep inside the skull radiating forward behind the eye",
"next": "exam-occipitalis-1"
}
]
},
"jaw-throat-split-1": {
"type": "symptom",
"question": "Alongside the back-of-head or posterior temporal pain, is there throat discomfort under the chin, swallowing difficulty, or lower incisor tooth sensitivity?",
"symptom_name": "Throat or submental discomfort; lower incisor sensitivity",
"muscles_implicated": ["Digastric (Posterior Belly)"],
"muscles_excluded": ["Temporalis CTrP₄"],
"clinical_rationale": "This question separates temporalis CTrP₄ (posterior temporal above and behind the ear, activated by retrusive bruxism — no throat involvement) from the posterior belly of the digastric (refers to the upper SCM region and occasionally to the occiput, with throat or submental discomfort — often follows masseter TrPs and is closely linked to swallowing mechanics). Lower incisor sensitivity is specific to the anterior belly, but its presence alongside occiput pain suggests the whole muscle is active.",
"yes": "exam-digastric-1",
"no": "exam-temporalis-ctrp4-1"
},
"exam-temporalis-ctrp4-1": {
"type": "examination",
"question": "Does flat palpation of the posterior belly of the temporalis — above and slightly behind the ear, in the midfibre region of the posterior fan — reproduce the back-of-head or posterior temporal pain?",
"exam_type": "palpation",
"landmark": "CTrP₄ is located in the midfibre region of the posterior belly of the temporalis, above and slightly posterior to the ear. It is a central TrP (not a musculotendinous attachment TrP). Palpate with firm flat pressure in this zone — it does NOT refer to the teeth, distinguishing it from ATrP₁–₃. Ask the patient: does this reproduce the familiar back-of-head or posterior temporal pain? Also ask about retrusive bruxism or a history of grinding the back teeth.",
"positive_finding": "Focal tenderness in the posterior temporalis belly above and behind the ear, reproducing posterior temporal or occipital pain. No tooth referral.",
"muscles_implicated": ["Temporalis CTrP₄"],
"yes": "result-temporalis-ctrp4",
"no": "autonomic-split-1"
},
"exam-digastric-1": {
"type": "examination",
"question": "Does palpation of the posterior belly of the digastric — along the line from the mastoid notch downward and forward to the intermediate tendon near the hyoid — reproduce the occipital or upper SCM pain? Does the Swallowing Test show restriction or discomfort (ask the patient to swallow while palpating)?",
"exam_type": "palpation",
"landmark": "Posterior belly: palpate along its course from the mastoid notch, passing deep to the lower SCM and anterior to the SCM toward the hyoid. Ask the patient to keep the jaw completely relaxed — any jaw tension will tighten the digastric and obscure the examination. Swallowing Test: with the index finger palpating the posterior belly, ask the patient to swallow a small amount of saliva — increased pain or tension confirms digastric involvement. Mandibular Deviation Sign: open the jaw slowly while observing — the mandible may deviate toward the side of active digastric TrPs on opening.",
"positive_finding": "Tenderness along the posterior belly course from mastoid notch toward the hyoid, reproducing upper SCM or occipital pain. Swallowing Test positive.",
"muscles_implicated": ["Digastric (Posterior Belly)"],
"yes": "result-digastric",
"no": "autonomic-split-1"
},
"autonomic-split-1": {
"type": "symptom",
"question": "Is there ipsilateral AUTONOMIC phenomena alongside the occipital or back-of-head pain — profuse tearing, rhinitis (watering or blocked nose), conjunctival redness, or apparent drooping of the eyelid on the same side?",
"symptom_name": "Autonomic phenomena — tearing, rhinitis, palpebral narrowing",
"muscles_implicated": ["SCM (Sternal Division)"],
"muscles_excluded": ["SCM (Clavicular Division)", "Upper Trapezius", "Posterior Cervical muscles"],
"clinical_rationale": "Autonomic phenomena are specific to the sternal division of the SCM — no other muscle in the back-of-head group produces tearing, rhinitis, or palpebral fissure narrowing. The sternal division refers to the occiput and vertex alongside its cheek and orbital patterns. Profuse tearing is often the most alarming symptom to the patient and is frequently misattributed to eye disease.",
"yes": "exam-scm-sternal-1",
"no": "dizziness-split-1"
},
"exam-scm-sternal-1": {
"type": "examination",
"question": "Does pincer palpation of the SCM sternal head — grasping the full muscle belly from mastoid to sternum — reproduce the occipital or back-of-head pain? Does the SCM Compression Test (gripping the belly during swallowing) resolve a concurrent sore throat?",
"exam_type": "palpation",
"landmark": "Patient supine, head rotated slightly toward the TrP side to relax the muscle. Grasp the full sternal belly in a pincer grip from the mastoid process down to the sternum. SCM Compression Test: firmly grip the belly and ask the patient to swallow — resolution of pharyngeal pain with compression is pathognomonic of a sternal central TrP. Note palpebral fissure width on both sides — narrowing on the TrP side without miosis is a confirmatory sign.",
"positive_finding": "Reproduces occipital, vertex, or back-of-head pain. SCM Compression Test may relieve concurrent sore throat.",
"muscles_implicated": ["SCM (Sternal Division)"],
"yes": "result-scm-sternal",
"no": "dizziness-split-1"
},
"dizziness-split-1": {
"type": "symptom",
"question": "Is there ipsilateral postural dizziness or imbalance accompanying the back-of-head pain — veering to one side when walking, sensation of imbalance when changing head position, or worsening when lying without pillow support?",
"symptom_name": "Postural dizziness / imbalance — non-vestibular",
"muscles_implicated": ["SCM (Clavicular Division)"],
"muscles_excluded": ["Upper Trapezius", "Posterior Cervical muscles"],
"clinical_rationale": "Postural dizziness without nystagmus is a cardinal feature of the clavicular division of the SCM. The clavicular division refers to the back of the head and the frontal region. The dizziness is non-vestibular — Romberg is negative and nystagmus is absent, distinguishing it from vestibular pathology. Worsening on lying without pillow support or on turning over in bed (requiring head lift rather than roll) are characteristic postural aggravators.",
"yes": "exam-scm-clavicular-1",
"no": "posterior-cervical-split-1"
},
"exam-scm-clavicular-1": {
"type": "examination",
"question": "Does flat palpation of the clavicular head of the SCM — from the medial clavicle upward toward the mastoid, pressing posteriorly just behind the sternal head — reproduce the back-of-head pain or provoke dizziness?",
"exam_type": "palpation",
"landmark": "With the patient supine and head rotated slightly toward the opposite side, use flat palpation of the clavicular (posterior) head, which lies deep and posterior to the sternal head. Palpate from the medial clavicle upward toward the mastoid, pressing posteriorly. Ask the patient to report reproduction of the familiar back-of-head pain OR any dizziness or sense of veering.",
"positive_finding": "Reproduces back-of-head pain or provokes dizziness and sense of imbalance",
"muscles_implicated": ["SCM (Clavicular Division)"],
"yes": "result-scm-clavicular",
"no": "posterior-cervical-split-1"
},
"posterior-cervical-split-1": {
"type": "choice",
"question": "Within the neck-aggravated group — which feature best characterises the quality and location of the back-of-head pain?",
"clinical_rationale": "The remaining six muscles — upper trapezius TrP₁, semispinalis capitis, semispinalis cervicis, splenius cervicis, suboccipital group, and occipitalis — are separated here by pain quality and location. Upper trapezius produces posterolateral neck-to-mastoid referral with ipsilateral head tilt and shoulder loading. The semispinalis capitis and cervicis produce occipital and encircling patterns worsened by neck flexion. Splenius cervicis and the suboccipital group produce diffuse intracranial or orbital referral. Occipitalis produces through-the-skull deep orbital pain — but since pillow intolerance was already screened at agg-1, the occipitalis arriving here has not declared itself by pillow intolerance and needs examination.",
"options": [
{
"label": "Posterolateral neck pain sweeping up to the mastoid and occiput — shoulder carrying or neck elevation worsens it",
"sublabel": "Head tends to tilt toward the pain side; ipsilateral shoulder ache; bag or coat on the same shoulder aggravates",
"next": "exam-trapezius-1"
},
{
"label": "Occipital and back-of-head pain worsened by neck FLEXION — looking down, reading, or computing",
"sublabel": "Checkrein mechanism; may feel like pressure at the base of the skull; may have a band-like quality spreading toward the temple",
"next": "semispinalis-split-1"
},
{
"label": "Diffuse intracranial or deep orbital referral — pain feels inside the skull radiating toward the eye",
"sublabel": "Deep, poorly localised, or 'ghostly' quality; may have near-vision blurring; neck rotation may be restricted",
"next": "splenius-suboccipital-split-1"
}
]
},
"exam-trapezius-1": {
"type": "examination",
"question": "Does pincer palpation of the upper trapezius TrP₁ — grasping the anterior border of the upper trapezius at its most vertical midportion — reproduce the posterolateral neck and occipital pain?",
"exam_type": "palpation",
"landmark": "TrP₁ is at the midportion of the anterior border of the upper trapezius, in the most vertical fibres. Grasp the anterior border in a firm pincer grip — the TrP often produces a local twitch response. TrP₁ refers upward along the posterolateral neck to the mastoid process; at higher intensity the pain sweeps over the temple and toward the back of the orbit. Note the patient's head position — ipsilateral head tilt (ear toward the TrP shoulder) is a consistent postural sign of upper trapezius shortening.",
"positive_finding": "Posterolateral neck-to-occiput pain reproduced by TrP₁ pincer palpation. Ipsilateral head tilt present.",
"muscles_implicated": ["Upper Trapezius (TrP₁)"],
"yes": "result-trapezius",
"no": "semispinalis-split-1"
},
"semispinalis-split-1": {
"type": "rom",
"question": "Does cervical flexion (chin toward chest) reproduce or intensify the occipital pain? Note range — does the chin reach within one to two finger-breadths of the sternum, or is it restricted?",
"movement": "Cervical flexion",
"direction": "aggravating",
"muscles_implicated": ["Semispinalis Capitis", "Semispinalis Cervicis"],
"clinical_rationale": "Both semispinalis capitis and semispinalis cervicis provide a checkrein function during neck flexion. Reproduction of occipital pain on controlled neck flexion implicates one or both. The distinction between them is made on palpation depth and pain distribution: semispinalis capitis refers in a band-like arc to the temporal region; semispinalis cervicis refers to the occipital region and down to the upper scapular border — a more caudal and deeper pattern.",
"yes": "semispinalis-depth-1",
"no": "splenius-suboccipital-split-1"
},
"semispinalis-depth-1": {
"type": "examination",
"question": "Where is the pain predominantly located — does it encircle toward the temporal region and eye (band-like), OR does it stay predominantly occipital and extend downward toward the upper scapular border?",
"exam_type": "palpation",
"landmark": "Palpate two depths: Semispinalis capitis (Location 1 enthesopathy at nuchal line 1–2 cm lateral to midline; Location 2 upper-third TrP at C₁ level — DO NOT inject here; Location 3 middle-third at C₃–C₄). Semispinalis cervicis: requires deeper palpation 1–2 cm lateral to the spinous processes at C₂–C₅ level — press through the semispinalis capitis layer. Cervicis TrPs refer to the occiput and downward toward the upper vertebral border of the scapula rather than arcing toward the temple.",
"positive_finding": "Superficial palpation (Location 2/3) reproduces band-like temporal arc = semispinalis capitis. Deeper palpation at C₂–C₅ level reproduces occipital + scapular border pain = semispinalis cervicis.",
"muscles_implicated": ["Semispinalis Capitis", "Semispinalis Cervicis"],
"yes": "result-semispinalis-capitis",
"no": "result-semispinalis-cervicis"
},
"splenius-suboccipital-split-1": {
"type": "symptom",
"question": "Is there ipsilateral blurring of NEAR vision — transient difficulty focusing on close objects on the same side as the occipital or orbital pain?",
"symptom_name": "Ipsilateral near-vision blurring",
"muscles_implicated": ["Splenius Cervicis"],
"muscles_excluded": ["Suboccipital Group", "Occipitalis"],
"clinical_rationale": "Ipsilateral near-vision blurring is pathognomonic for splenius cervicis upper TrP — no other muscle in the back-of-head group produces this feature. Its absence shifts probability toward the suboccipital group (diffuse ghostly pain, AA rotation restricted) or occipitalis (through-the-skull deep orbital pain, pillow intolerance).",
"yes": "exam-splenius-1",
"no": "suboccipital-occipitalis-split-1"
},
"exam-splenius-1": {
"type": "examination",
"question": "Does deep palpation through the trapezius at the C₁–C₃ level — approximately 3–4 cm lateral to the midline — reproduce the diffuse orbital or intracranial pain and near-vision blurring? Is cervical rotation restricted toward the involved side?",
"exam_type": "palpation",
"landmark": "The splenius cervicis lies beneath the trapezius and is not directly accessible from behind. Press firmly through the trapezius at C₁–C₃ level, 3–4 cm lateral to the midline. The upper TrP refers a diffuse pain through the inside of the head to the back of the eye. Active rotation restriction: ask the patient to rotate toward the involved side — end-range restriction or provocation of the orbital pain is a consistent finding. This muscle often only becomes accessible after levator scapulae TrPs have been inactivated.",
"positive_finding": "Deep palpation through trapezius reproduces diffuse orbital or intracranial pain. Near-vision blurring provoked or present. Cervical rotation restricted toward the involved side.",
"muscles_implicated": ["Splenius Cervicis"],
"yes": "result-splenius-cervicis",
"no": "suboccipital-occipitalis-split-1"
},
"suboccipital-occipitalis-split-1": {
"type": "symptom",
"question": "Is the pain quality DIFFUSE and poorly localised — described as deep, ghostly, or 'all over inside the skull'? AND is there restriction of atlantoaxial rotation (inability to rotate the head purely at C₁/C₂ with the neck in slight flexion)?",
"symptom_name": "Diffuse ghostly intracranial quality + AA rotation restriction",
"muscles_implicated": ["Suboccipital Group"],
"muscles_excluded": ["Occipitalis"],
"clinical_rationale": "The suboccipital group produces the most diffuse and poorly localised back-of-head pain — patients describe it as hurting 'all over inside.' Atlantoaxial rotation restriction (tested with the neck in slight flexion to lock the lower cervical spine and isolate C₁/C₂) is a consistent examination finding. If the pain quality is more focal — through-the-skull to behind the eye — without the ghostly diffuse quality, the occipitalis is more likely.",
"yes": "exam-suboccipital-1",
"no": "exam-occipitalis-1"
},
"exam-suboccipital-1": {
"type": "examination",
"question": "Does deep suboccipital palpation just below the nuchal line — between the midline and the mastoid — reproduce the diffuse deep head pain? Is atlantoaxial rotation (head rotation with neck slightly flexed) restricted?",
"exam_type": "palpation",
"landmark": "Palpate firmly in the suboccipital triangle, inferior to the nuchal line between the midline and the mastoid process. The characteristic reproduction is diffuse, poorly localised aching that feels penetrating or 'all over inside.' AA rotation test: patient supine, examiner rotates the head with the neck in slight flexion (chin slightly tucked to lock lower cervical joints) — restriction of pure C₁/C₂ rotation confirms AA involvement. CAUTION: the vertebral artery traverses the suboccipital triangle — injection should only be performed by practitioners expert in the anatomy.",
"positive_finding": "Deep suboccipital palpation reproduces diffuse poorly localised head pain. AA rotation restricted.",
"muscles_implicated": ["Suboccipital Group"],
"yes": "result-suboccipital",
"no": "exam-occipitalis-1"
},
"exam-occipitalis-1": {
"type": "examination",
"question": "Does flat palpation of the occipitalis belly — in the small hollow just above the superior nuchal line, approximately 4 cm lateral to the midline — reproduce a deep aching pain through the skull or behind the eye? Does the patient report inability to rest the back of the head on a pillow due to pain?",
"exam_type": "palpation",
"landmark": "Occipitalis TrP: palpate in the small hollow just above the superior nuchal line, approximately 4 cm lateral to the midline, in the subcutaneous fascia over the occiput. The muscle is superficial — press firmly through the scalp skin. Pillow intolerance: a TrP here makes it impossible to bear the weight of the head on a pillow at night — the patient must sleep on their side. Apply moist heat to the occiput: if this relieves the pain, it is myofascial (favours occipitalis TrPs over nerve entrapment).",
"positive_finding": "Focal tenderness in the occipitalis belly reproducing through-the-skull deep orbital pain. Pillow intolerance reported. Moist heat relieves the pain.",
"muscles_implicated": ["Occipitalis (Occipitofrontalis)"],
"yes": "result-occipitalis",
"no": "result-overlap"
},
"result-temporalis-ctrp4": {
"type": "result",
"diagnosis": "Temporalis CTrP₄ — Posterior Belly Central Trigger Point",
"confidence": "high",
"wiki_page": "Muscle:Temporalis",
"chapter_ref": "Travell & Simons Vol.1 — Ch.9 Temporalis",
"notes": "CTrP₄ is a central TrP in the midfibre region of the posterior belly of the temporalis, located above and slightly behind the ear. It refers pain backward and upward over the posterior temporal region — producing back-of-head and posterior temporal pain without the tooth referral characteristic of ATrP₁–₃. It is specifically activated by retrusive bruxism (grinding the posterior teeth in a backward jaw movement), which distinguishes it from the anterior TrPs activated by clenching and chewing. Treating CTrP₄ requires addressing the retrusive bruxism habit and any occlusal factors that drive posterior tooth grinding.",
"treatment_hint": "Flat palpation and ischemic compression over the posterior belly. Address retrusive bruxism — a night guard with posterior contact may help. Treat upper trapezius and SCM key TrPs concurrently. The temporal artery runs through the muscle — identify it before injection.",
"also_consider": ["Upper Trapezius (key TrP)", "SCM Sternal (key TrP)", "Digastric Posterior Belly"],
"less_likely": [
{ "muscle": "Semispinalis Capitis", "reason": "No neck flexion aggravation; jaw activity (retrusive bruxism) is the primary activator for CTrP₄" },
{ "muscle": "Upper Trapezius", "reason": "No shoulder loading as primary aggravator; posterior temporal location above and behind the ear is specific to CTrP₄" },
{ "muscle": "Digastric Posterior", "reason": "No throat or swallowing symptoms; CTrP₄ is activated by retrusive bruxism rather than masticatory-chain dysfunction" }
],
"confirmatory": [
"CTrP₄ tenderness above and slightly behind the ear in the posterior belly midfibre zone — reproducing the familiar back-of-head pain",
"No tooth referral — distinguishes CTrP₄ from ATrP₁–₃ which refer to the upper teeth",
"History of retrusive bruxism — posterior tooth grinding confirmed by wear facets or patient report",
"Temporal artery confirmed pulsatile — non-pulsatile tender artery requires temporal arteritis exclusion"
],
"satellite_trps": ["Masseter", "SCM (Sternal Division)", "Upper Trapezius"],
"landing_page_topics": [
"CTrP₄ vs ATrP₁–₃ — retrusive bruxism vs clenching distinction",
"Temporal artery anatomy and injection caution",
"Satellite relationship with upper trapezius and SCM"
],
"related_pages": [
{ "label": "Temporalis full page →", "page": "Muscle:Temporalis" },
{ "label": "Upper Trapezius TrPs →", "page": "Muscle:Trapezius/Upper" }
]
},
"result-digastric": {
"type": "result",
"diagnosis": "Digastric — Posterior Belly Trigger Point",
"confidence": "moderate",
"wiki_page": "Muscle:Digastric",
"chapter_ref": "Travell & Simons Vol.1 — Ch.12 Digastric",
"notes": "The posterior belly of the digastric refers pain to the upper SCM region — a pattern so convincingly similar to SCM TrP pain that it is called pseudo-sternocleidomastoid pain. An occasional spillover extends to the occiput. The digastric nearly always develops TrPs secondary to masseter TrPs rather than in isolation — systematic treatment of the masseter is essential. The mutual satellite relationship with the SCM (either can drive the other) means both must be examined whenever either is involved. Mandibular deviation on jaw opening toward the side of active TrPs is a useful clinical sign. Eagle syndrome (elongated styloid process) must be excluded when posterior belly TrPs are recalcitrant.",
"treatment_hint": "Treat masseter TrPs first — digastric is frequently their satellite. Spray and stretch the posterior belly. Swallowing Test confirms involvement. Assess hyoid mobility — restricted lateral hyoid shift indicates tension in the suprahyoid muscles. Eagle syndrome exclusion: if pain is reproduced by intraoral palpation in the tonsillar fossa or provoked by head turning, request panoramic radiograph.",
"also_consider": ["Masseter (key TrP)", "SCM Sternal Division", "Medial Pterygoid", "Stylohyoid"],
"less_likely": [
{ "muscle": "SCM Sternal Division", "reason": "No autonomic phenomena; swallowing symptoms and pseudo-SCM pattern argue for digastric posterior belly" },
{ "muscle": "Temporalis CTrP₄", "reason": "Throat and swallowing symptoms present — these are specific to the digastric, not temporalis" },
{ "muscle": "Upper Trapezius", "reason": "No shoulder loading; pseudo-SCM pattern with swallowing involvement is specific to digastric posterior belly" }
],
"confirmatory": [
"Tenderness along the posterior belly from mastoid notch toward the hyoid — reproducing upper SCM or occipital pain",
"Swallowing Test positive — increased pain or tension in the posterior belly during swallowing",
"Mandibular Deviation Sign — jaw deviates toward the side of active TrPs on slow jaw opening",
"Masseter TrPs identified — digastric is almost always secondary to masseter dysfunction",
"Eagle syndrome excluded — no pain on intraoral palpation in the tonsillar fossa"
],
"satellite_trps": ["Masseter (key TrP)", "SCM Sternal Division", "Medial Pterygoid", "Mylohyoid"],
"landing_page_topics": [
"Pseudo-SCM pain — posterior belly vs SCM sternal comparison",
"Anterior belly and lower incisor tooth pain",
"Swallowing Test and hyoid mobility assessment",
"Eagle syndrome exclusion",
"Mandibular Deviation Sign"
],
"related_pages": [
{ "label": "SCM TrP →", "page": "Muscle:Sternocleidomastoid" },
{ "label": "Masseter TrP →", "page": "Muscle:Masseter" }
]
},
"result-scm-sternal": {
"type": "result",
"diagnosis": "SCM Trigger Point — Sternal Division",
"confidence": "high",
"wiki_page": "Muscle:Sternocleidomastoid",
"chapter_ref": "Travell & Simons Vol.1 — Ch.7 Sternocleidomastoid",
"notes": "The sternal division refers to the occiput and vertex alongside its cheek, orbit, and temple patterns. In the back-of-head context, the autonomic phenomena — profuse tearing, rhinitis, palpebral fissure narrowing — are the cardinal distinguishing features that no other muscle in this region produces. Head tilts toward the TrP side due to pain on holding the head upright. The patient prefers to lie with a pillow supporting the head so the sore face does not bear weight.",
"treatment_hint": "Pincer palpation and spray and stretch, superior to inferior. SCM Compression Test confirms sternal central TrP. Correct forward head posture. Treating sternal SCM often resolves satellite TrPs in the face, scalp, and temporalis.",
"also_consider": ["SCM Clavicular Division", "Upper Trapezius", "Temporalis (satellite)"],
"less_likely": [
{ "muscle": "Upper Trapezius TrP₁", "reason": "Autonomic phenomena are specific to the SCM sternal division — not present with trapezius TrPs" },
{ "muscle": "Semispinalis Capitis", "reason": "No encircling band quality; autonomic phenomena do not arise from posterior cervical muscles" },
{ "muscle": "SCM Clavicular Division", "reason": "Autonomic phenomena present — clavicular division produces dizziness, not tearing or rhinitis" }
],
"confirmatory": [
"SCM Compression Test positive — pharyngeal pain resolves on gripping the sternal belly during swallowing",
"Profuse ipsilateral tearing — often the most alarming symptom",
"Rhinitis on TrP side — ipsilateral nasal congestion or watering without infection",
"Apparent ptosis without miosis — confirm pupils equal and reactive",
"Head tilts toward TrP side; lies on sore side with pillow"
],
"satellite_trps": ["Temporalis", "Zygomaticus Major", "Orbicularis Oculi", "Masseter"],
"landing_page_topics": [
"Sternal vs clavicular division — full symptom profiles",
"Horner syndrome exclusion protocol",
"CN XI entrapment and trapezius weakness",
"Satellite TrP treatment sequence"
],
"related_pages": [
{ "label": "Upper Trapezius TrPs →", "page": "Muscle:Trapezius/Upper" },
{ "label": "Temporalis TrP →", "page": "Muscle:Temporalis" }
]
},
"result-scm-clavicular": {
"type": "result",
"diagnosis": "SCM Trigger Point — Clavicular Division",
"confidence": "high",
"wiki_page": "Muscle:Sternocleidomastoid",
"chapter_ref": "Travell & Simons Vol.1 — Ch.7 Sternocleidomastoid",
"notes": "The clavicular division refers to the back of the head and the frontal region. The back-of-head pain is aggravated by neck posture and head loading. Any of three presentations may dominate: back-of-head and frontal headache, postural dizziness and imbalance, or dysmetria (disturbed weight perception). There are NO autonomic phenomena — the absence of tearing and rhinitis distinguishes this from the sternal division. Dizziness worsens when lying without pillow support or on rapid head rotation.",
"treatment_hint": "Flat palpation and spray and stretch of the clavicular head from clavicle upward. Correct forward head posture. Advise rolling the head on the pillow rather than lifting it when turning in bed.",
"also_consider": ["SCM Sternal Division", "Upper Trapezius", "Semispinalis Capitis"],
"less_likely": [
{ "muscle": "SCM Sternal Division", "reason": "No autonomic phenomena — tearing, rhinitis, and palpebral narrowing absent" },
{ "muscle": "Upper Trapezius", "reason": "Dizziness and postural imbalance are specific to clavicular SCM; not produced by trapezius" },
{ "muscle": "Suboccipital Group", "reason": "Dizziness with postural character and no AA rotation restriction points to clavicular SCM" }
],
"confirmatory": [
"Back-of-head pain reproduced by flat palpation of the clavicular head",
"Straight-line walking test: veers toward the TrP side — confirms clavicular division",
"Romberg negative and nystagmus absent — distinguishes from vestibular pathology",
"No autonomic phenomena — no tearing, rhinitis, or palpebral narrowing",
"Dizziness worsened by lying without pillow or rapid rotation"
],
"satellite_trps": ["Frontalis", "Orbicularis Oculi", "Scalene muscles"],
"landing_page_topics": [
"Dizziness differentiation — vestibular vs non-vestibular: Romberg, straight-line walk",
"Hearing restoration manoeuvre",
"Dysmetria and weight perception testing",
"Satellite TrP sequence — SCM clavicular before frontalis"
],
"related_pages": [
{ "label": "SCM full page →", "page": "Muscle:Sternocleidomastoid" },
{ "label": "Upper Trapezius TrPs →", "page": "Muscle:Trapezius/Upper" }
]
},
"result-trapezius": {
"type": "result",
"diagnosis": "Upper Trapezius TrP₁ — Posterolateral Neck and Occipital Referral",
"confidence": "high",
"wiki_page": "Muscle:Trapezius",
"chapter_ref": "Travell & Simons Vol.1 — Ch.6 Trapezius",
"notes": "TrP₁ at the anterior border of the upper trapezius refers upward along the posterolateral neck to the mastoid process and at higher intensity over the temple toward the back of the orbit. It is the most frequently identified myofascial TrP location in the entire body. Ipsilateral head tilt — the ear drawn toward the shoulder on the TrP side — is a consistent postural sign of upper trapezius shortening. Upper trapezius is also a key TrP that drives temporalis, SCM, and semispinalis capitis as satellites — treating it first is essential.",
"treatment_hint": "Pincer palpation and spray and stretch with side-bending away and contralateral rotation. Correct shoulder elevation — bags on the ipsilateral shoulder are the most common perpetuating factor. Levator scapulae may co-activate and should also be treated.",
"also_consider": ["Levator Scapulae", "SCM", "Temporalis (satellite)", "Semispinalis Capitis (satellite)"],
"less_likely": [
{ "muscle": "SCM Sternal Division", "reason": "No autonomic phenomena; shoulder loading is the primary aggravator, not head posture" },
{ "muscle": "Semispinalis Capitis", "reason": "No encircling band quality; shoulder loading distinguishes trapezius from semispinalis" },
{ "muscle": "Suboccipital Group", "reason": "Focal posterolateral referral to mastoid/occiput is distinct from the diffuse ghostly suboccipital pattern" }
],
"confirmatory": [
"TrP₁ tenderness at the anterior border of the upper trapezius — most common TrP in the body; local twitch response often elicited",
"Posterolateral neck-to-occiput pain reproduced — not just local tenderness",
"Ipsilateral head tilt — ear toward shoulder on TrP side",
"Shoulder carrying on the same side reproduces or worsens the occipital headache"
],
"satellite_trps": ["Temporalis", "SCM", "Semispinalis Capitis", "Levator Scapulae"],
"landing_page_topics": [
"TrP₁ through TrP₇ referral patterns",
"Autonomic phenomena from TrP₁",
"Shoulder carry and workstation correction",
"Satellite relationship with temporalis and SCM"
],
"related_pages": [
{ "label": "Temporalis TrP →", "page": "Muscle:Temporalis" },
{ "label": "Levator Scapulae TrP →", "page": "Muscle:Levator_Scapulae" }
]
},
"result-semispinalis-capitis": {
"type": "result",
"diagnosis": "Semispinalis Capitis Trigger Point",
"confidence": "high",
"wiki_page": "Muscle:Semispinalis_Capitis",
"chapter_ref": "Travell & Simons Vol.1 — Ch.16 Semispinalis Capitis",
"notes": "Upper and middle TrPs produce a band-like headache encircling from the occiput through the temporal region forward over the eye. The nuchal line enthesopathy (Location 1) reflects sustained tension from TrPs in the upper-third midbelly (Location 2) — the causal TrP is lower than the pain. Greater occipital nerve entrapment by taut bands adds a superficial tingling or hot prickling component to the deep aching referral. Both may coexist. The checkrein loading mechanism means sustained reading, computing, or sewing with forward head posture chronically activates TrPs.",
"treatment_hint": "Spray and stretch with neck extension. Moist heat. DO NOT inject Location 2 (vertebral artery proximity at C₁ level). Treat upper trapezius and splenius capitis key TrPs first — semispinalis capitis is frequently their satellite.",
"also_consider": ["Upper Trapezius (key TrP)", "Splenius Capitis (key TrP)", "Semispinalis Cervicis", "Suboccipital Group"],
"less_likely": [
{ "muscle": "Semispinalis Cervicis", "reason": "Band-like arc to the temple is specific to semispinalis capitis; cervicis refers occipitally and to the scapular border" },
{ "muscle": "Upper Trapezius", "reason": "Encircling band with neck flexion aggravation is specific to semispinalis; no shoulder loading as primary aggravator" },
{ "muscle": "Suboccipital Group", "reason": "Band-like temporal arc is distinct from the diffuse ghostly suboccipital quality" }
],
"confirmatory": [
"Band-like headache encircling from occiput through temple to over the eye",
"Cervical flexion reproduces or intensifies the occipital and band headache",
"Enthesopathy at the nuchal line (Location 1) — 1–2 cm lateral to midline",
"Midbelly TrP at Location 2 or 3 reproduces the band headache — the causal TrP",
"Greater occipital nerve entrapment may add superficial tingling to the deep aching pattern"
],
"satellite_trps": ["Suboccipital Group", "Semispinalis Cervicis", "Multifidi", "Upper Trapezius"],
"landing_page_topics": [
"Three TrP locations — injection caution at Location 2",
"Greater occipital nerve entrapment",
"Checkrein mechanism and forward head posture",
"Satellite relationship with upper trapezius and splenius capitis"
],
"related_pages": [
{ "label": "Upper Trapezius TrPs →", "page": "Muscle:Trapezius/Upper" },
{ "label": "Suboccipital Group →", "page": "Muscle:Suboccipital" }
]
},
"result-semispinalis-cervicis": {
"type": "result",
"diagnosis": "Semispinalis Cervicis Trigger Point",
"confidence": "moderate",
"wiki_page": "Muscle:Semispinalis_Cervicis",
"chapter_ref": "Travell & Simons Vol.1 — Ch.16 Semispinalis Cervicis",
"notes": "Semispinalis cervicis TrPs refer pain into the occipital region in a pattern similar to the middle semispinalis capitis (Location 3 pattern), and additionally downward over the neck to the upper vertebral border of the scapula. This caudal extension to the scapular border is the key feature distinguishing cervicis from capitis. Like the semispinalis capitis, it provides a checkrein function during neck flexion — sustained reading and computing with forward head posture chronically load it. Its TrPs are typically part of a multi-muscle posterior cervical complex. Deep palpation — approximately 1–2 cm lateral to the spinous processes at C₂–C₅ — is required to access TrPs through the overlying semispinalis capitis layer.",
"treatment_hint": "Spray and stretch with neck extension and slight contralateral rotation. Deep palpation technique. Correct forward head posture. Treat the semispinalis capitis and upper trapezius first — semispinalis cervicis is frequently part of a multi-muscle complex and is reached after the more superficial layers.",
"also_consider": ["Semispinalis Capitis", "Upper Trapezius (key TrP)", "Multifidi", "Suboccipital Group"],
"less_likely": [
{ "muscle": "Semispinalis Capitis", "reason": "Scapular border extension of pain and deeper palpation required argues for cervicis; capitis has the encircling temporal arc" },
{ "muscle": "Upper Trapezius", "reason": "Neck flexion checkrein aggravation and deep posterior cervical location distinguish cervicis from trapezius" },
{ "muscle": "Splenius Cervicis", "reason": "No near-vision blurring and no rotation restriction; flexion checkrein is the key mechanism here" }
],
"confirmatory": [
"Occipital pain extending downward to the upper vertebral border of the scapula — the scapular extension distinguishes cervicis from capitis",
"Cervical flexion reproduces the occipital pain — checkrein mechanism",
"Deeper palpation 1–2 cm lateral to spinous processes at C₂–C₅ required — more superficial palpation reaches semispinalis capitis only",
"C₂–C₃ zygapophysial joint dysfunction must be considered in the differential — refer if articular component suspected"
],
"satellite_trps": ["Semispinalis Capitis", "Multifidi", "Rotatores", "Upper Trapezius"],
"landing_page_topics": [
"Anatomy and palpation depth — distinguishing from semispinalis capitis",
"C₂–C₃ zygapophysial joint differential",
"Checkrein mechanism — identical to semispinalis capitis",
"Multi-muscle posterior cervical complex"
],
"related_pages": [
{ "label": "Semispinalis Capitis →", "page": "Muscle:Semispinalis_Capitis" },
{ "label": "Upper Trapezius TrPs →", "page": "Muscle:Trapezius/Upper" }
]
},
"result-splenius-cervicis": {
"type": "result",
"diagnosis": "Splenius Cervicis Trigger Point",
"confidence": "moderate",
"wiki_page": "Muscle:Splenius_Cervicis",
"chapter_ref": "Travell & Simons Vol.1 — Ch.15 Splenius Cervicis",
"notes": "The upper TrP of the splenius cervicis refers a diffuse pain through the inside of the head to the back of the eye — an intracranial quality. Ipsilateral near-vision blurring is highly specific and pathognomonic for this muscle. The lower TrP produces pain at the angle of the neck and upper shoulder. The muscle lies beneath the trapezius and levator scapulae — it is not readily palpable from behind, and involvement often only becomes apparent after those overlying muscles have been treated.",
"treatment_hint": "Treat levator scapulae and upper trapezius first. Spray and stretch with contralateral rotation and slight flexion. Correct sustained ipsilateral rotation postures.",
"also_consider": ["Upper Trapezius (key TrP)", "Levator Scapulae (key TrP)", "Splenius Capitis", "Suboccipital Group"],
"less_likely": [
{ "muscle": "Suboccipital Group", "reason": "Near-vision blurring is specific to splenius cervicis; suboccipital pain is diffuse and ghostly without the vision component" },
{ "muscle": "Semispinalis Capitis", "reason": "No encircling band quality; orbital referral with vision blur distinguishes splenius cervicis" },
{ "muscle": "Upper Trapezius", "reason": "Orbital and intracranial referral with vision blur does not arise from trapezius TrP₁" }
],
"confirmatory": [
"Ipsilateral near-vision blurring — pathognomonic for splenius cervicis upper TrP",
"Diffuse intracranial pain to back of eye — deep inside the head quality",
"Cervical rotation restricted toward the involved side",
"Deep palpation through trapezius at C₁–C₃ reproduces the orbital pain",
"Becomes apparent after levator scapulae and upper trapezius TrPs have been treated"
],
"satellite_trps": ["Suboccipital Group", "Splenius Capitis", "Levator Scapulae (key TrP)"],
"landing_page_topics": [
"Near-vision blurring mechanism",
"Upper vs lower TrP — intracranial referral vs angle-of-neck pain",
"Palpation through trapezius",
"Satellite relationship with levator scapulae and upper trapezius"
],
"related_pages": [
{ "label": "Levator Scapulae TrP →", "page": "Muscle:Levator_Scapulae" },
{ "label": "Suboccipital Group →", "page": "Muscle:Suboccipital" }
]
},
"result-suboccipital": {
"type": "result",
"diagnosis": "Suboccipital Group Trigger Points",
"confidence": "moderate",
"wiki_page": "Muscle:Suboccipital",
"chapter_ref": "Travell & Simons Vol.1 — Ch.17 Suboccipital Muscles",
"notes": "Suboccipital TrPs produce characteristically diffuse, poorly localised deep head pain — described as ghostly, penetrating, or 'all over inside.' Pain radiates from the occiput toward the eye and forehead. These muscles cannot be individually identified by palpation alone — involvement is inferred from movement restrictions, particularly atlantoaxial rotation. They nearly always develop as satellites of semispinalis capitis or splenius capitis rather than in isolation — treating the key muscles first is the correct approach. Forward head posture is the most consistent perpetuating factor.",
"treatment_hint": "Treat semispinalis capitis and splenius capitis key TrPs first. Suboccipital decompression technique (occipital hold with gentle sustained traction). Keep the suboccipital region warm. CAUTION on injection — vertebral artery traverses the suboccipital triangle.",
"also_consider": ["Semispinalis Capitis (key TrP)", "Splenius Capitis (key TrP)", "Upper Trapezius", "Splenius Cervicis"],
"less_likely": [
{ "muscle": "Splenius Cervicis", "reason": "No near-vision blurring; ghostly diffuse quality and AA rotation restriction distinguish suboccipital" },
{ "muscle": "Upper Trapezius", "reason": "Diffuse penetrating quality and AA rotation restriction are distinct from trapezius focal posterolateral referral" },
{ "muscle": "Occipitalis", "reason": "Suboccipital pain is diffuse and poorly localised; occipitalis pain is more focused through-the-skull to behind the eye with pillow intolerance" }
],
"confirmatory": [
"Diffuse poorly localised deep head pain — described as penetrating or 'all over inside the skull'",
"Deep suboccipital palpation below the nuchal line reproduces the diffuse pain",
"Atlantoaxial rotation restricted — tested with neck in slight flexion",
"Occipitoatlantal extension restricted",
"Nearly always satellite TrPs — semispinalis capitis and splenius capitis confirmed as key TrPs"
],
"satellite_trps": ["Semispinalis Cervicis", "Multifidi", "Upper Trapezius (key TrP)", "Splenius Capitis (key TrP)"],
"landing_page_topics": [
"AA and OA examination technique",
"Suboccipital decompression technique",
"Vertebral artery anatomy and injection caution",
"Satellite relationship with semispinalis and splenius capitis"
],
"related_pages": [
{ "label": "Semispinalis Capitis →", "page": "Muscle:Semispinalis_Capitis" },
{ "label": "Splenius Capitis TrP →", "page": "Muscle:Splenius_Capitis" }
]
},
"result-occipitalis": {
"type": "result",
"diagnosis": "Occipitalis Trigger Point (Occipitofrontalis — Occipital Belly)",
"confidence": "moderate",
"wiki_page": "Muscle:Occipitofrontalis",
"chapter_ref": "Travell & Simons Vol.1 — Ch.14 Occipitofrontalis",
"notes": "The occipitalis belly refers pain diffusely over the back of the head and through the cranium, causing intense deep pain behind the eye — a through-the-skull referral pattern that is distinctive. The patient cannot bear the weight of the back of the head on a pillow at night and must sleep on their side. Moist heat applied to the occiput relieves the pain, distinguishing myofascial from nerve entrapment origin. Occipitalis TrPs most commonly develop as satellites of posterior cervical TrPs — semispinalis cervicis and posterior digastric referring pain to the occipital region activate occipitalis as a satellite. Experimental injection of the galea between the two bellies reproduced pain homolaterally behind the eye and in the eyelids.",
"treatment_hint": "Treat semispinalis cervicis and posterior digastric key TrPs first — occipitalis is nearly always a satellite. Moist heat to the occiput. Flat palpation and ischemic compression. Occipital nerve entrapment must be distinguished from myofascial referral: nerve entrapment produces superficial tingling and hot prickling in the scalp distribution; occipitalis TrPs produce deep aching through-the-skull pain; moist heat relieves myofascial, not neuritic pain.",
"also_consider": ["Semispinalis Cervicis (key TrP)", "Posterior Digastric (key TrP)", "Greater Occipital Nerve Entrapment"],
"less_likely": [
{ "muscle": "Suboccipital Group", "reason": "Through-the-skull deep orbital referral and pillow intolerance are specific to occipitalis; suboccipital pain is more diffuse and ghostly" },
{ "muscle": "Semispinalis Capitis", "reason": "No encircling band quality; occipitalis pain is posterior-to-orbital rather than encircling-to-temporal" },
{ "muscle": "Splenius Cervicis", "reason": "No near-vision blurring; through-the-skull and pillow intolerance are specific to occipitalis" }
],
"confirmatory": [
"Cannot bear weight of back of head on pillow at night — must sleep on side; the defining clinical sign",
"Focal tenderness in the small hollow above the superior nuchal line approximately 4 cm lateral to midline",
"Through-the-skull referral to behind the eye — deep aching, not superficial tingling",
"Moist heat to the occiput relieves the pain — distinguishes myofascial from nerve entrapment",
"Confirm semispinalis cervicis and posterior digastric TrPs as likely key TrPs driving occipitalis as a satellite"
],
"satellite_trps": ["Frontalis", "Semispinalis Cervicis (key TrP)", "Posterior Digastric (key TrP)"],
"landing_page_topics": [
"Through-the-skull referral pattern — deep aching vs superficial tingling distinction",
"Pillow intolerance as the diagnostic sign",
"Moist heat test — myofascial vs nerve entrapment",
"Satellite relationship with posterior cervical muscles",
"Greater occipital nerve entrapment exclusion"
],
"related_pages": [
{ "label": "Occipitofrontalis full page →", "page": "Muscle:Occipitofrontalis" },
{ "label": "Semispinalis Cervicis →", "page": "Muscle:Semispinalis_Cervicis" },
{ "label": "Digastric TrP →", "page": "Muscle:Digastric" }
]
},
"result-overlap": {
"type": "overlap",
"text": "Findings are inconclusive. Multi-muscle involvement is common in back-of-head pain — upper trapezius is frequently the key TrP activating several others as satellites. Perform a systematic screen in order of clinical priority.",
"screen_these": [
"Upper Trapezius TrP₁ — pincer palpation of the anterior border at the most vertical midportion; note head tilt and shoulder loading",
"SCM both divisions — sternal head pincer palpation with SCM Compression Test; clavicular head flat palpation; note autonomic phenomena and dizziness separately",
"Semispinalis capitis — nuchal line and midbelly; cervical flexion reproduction test",
"Semispinalis cervicis — deeper palpation 1–2 cm lateral to spinous processes at C₂–C₅",
"Occipitalis — small hollow 4 cm lateral to midline above nuchal line; pillow intolerance; moist heat test",
"Splenius cervicis — deep palpation through trapezius at C₁–C₃; near-vision blurring; rotation restriction",
"Suboccipital group — palpation below nuchal line; AA rotation test",
"Digastric posterior belly — along mastoid notch to hyoid; Swallowing Test; hyoid mobility"
],
"wiki_page": "Differential:Back_Of_Head_Pain"
}
},
"broad_differential": [
{
"id": "bd-1",
"condition": "Occipital Neuralgia",
"confidence": "rare",
"mimics": "Occipital and back-of-head pain — overlaps with semispinalis capitis, suboccipital, and occipitalis patterns",
"distinguishing_feature": "Paroxysmal stabbing with aching between attacks. Radiation to frontal and orbital regions. The greater occipital nerve may be entrapped by semispinalis capitis taut bands producing both neuritic pain (superficial tingling, hot prickling) and myofascial aching simultaneously. Moist heat relieves myofascial pain but not neuritic pain. Always treat TrPs first before neuroablative procedures.",
"action": "Treat semispinalis capitis and posterior cervical TrPs first. If neuritic component persists after adequate TrP treatment, refer to neurology. Moist heat test helps distinguish."
},
{
"id": "bd-2",
"condition": "Cervicogenic Headache",
"confidence": "uncommon",
"mimics": "Unilateral occipital and posterior head pain precipitated by neck movement — overlaps with SCM, upper trapezius, and semispinalis patterns",
"distinguishing_feature": "Consistent unilaterality, precipitation by specific neck movements, associated shoulder and arm pain. Most cervicogenic headache patients have myofascial TrPs reproducing their headache. Reduced cervical segmental mobility accompanies the TrPs.",
"action": "Conservative myofascial TrP management first. Treat TrPs before attributing restriction to fibrous fixation or proceeding to invasive treatments."
},
{
"id": "bd-3",
"condition": "Eagle Syndrome",
"confidence": "rare",
"mimics": "Posterior neck and occipital pain with throat discomfort — overlaps with digastric posterior belly and SCM patterns",
"distinguishing_feature": "Pain provoked by turning the head or swallowing. Elongated styloid process palpable in the tonsillar fossa on intraoral examination. Digastric posterior belly TrPs are commonly associated and should be treated first.",
"action": "If digastric posterior TrPs are recalcitrant, perform intraoral palpation in the tonsillar fossa. Panoramic radiograph to assess styloid length. Refer to oral/maxillofacial surgery."
},
{
"id": "bd-4",
"condition": "Tension-type Headache",
"confidence": "uncommon",
"mimics": "Bilateral pressing occipital pain — overlaps with bilateral upper trapezius and semispinalis capitis TrP patterns",
"distinguishing_feature": "Very high probability of myofascial TrP involvement. Pericranial muscle tenderness is the consistent finding. EMG activity is not elevated in tension-type headache — the pain arises from TrPs, not sustained contraction.",
"action": "Systematic TrP screen of all posterior cervical and pericranial muscles. Myofascial treatment with perpetuating factor correction is first-line."
},
{
"id": "bd-5",
"condition": "Atlantoaxial Instability or OA Dysfunction",
"confidence": "rare",
"mimics": "Deep occipital pain with cervical rotation restriction — overlaps with suboccipital group TrP pattern",
"distinguishing_feature": "True AA instability has neurological signs (myelopathy, upper motor neuron signs). Articular dysfunction without instability produces restricted AA rotation with reproduction of occipital pain on the restriction end-feel. Suboccipital TrPs and AA articular dysfunction commonly coexist.",
"action": "If AA rotation is restricted, clear instability before manual treatment. Upper cervical joint mobilisation and TrP treatment are often complementary."
},
{
"id": "bd-6",
"condition": "Post-traumatic Headache",
"confidence": "uncommon",
"mimics": "Occipital and back-of-head pain following whiplash — semispinalis capitis and splenius capitis are the most commonly activated TrPs after motor vehicle accidents",
"distinguishing_feature": "History of trauma. Clinically indistinguishable from tension-type headache. Semispinalis capitis and splenius capitis are most commonly involved regardless of impact direction. The occipital referral from these muscles is the dominant pattern in many post-traumatic cases.",
"action": "Systematic TrP screen with priority on semispinalis capitis, SCM, upper trapezius, and splenius capitis. Refer if neurological symptoms suggest brainstem or vestibular involvement."
},
{
"id": "bd-7",
"condition": "Intracranial Hypertension (Idiopathic)",
"confidence": "rare",
"mimics": "Bilateral posterior head pain worse in the morning — overlaps with bilateral posterior cervical TrP patterns",
"distinguishing_feature": "Headache worse on waking, worsened by Valsalva, bending forward, or lying down. Pulsatile tinnitus. Visual obscurations (brief visual blackouts on postural change). Papilloedema on fundoscopy. Predominantly affects young overweight women.",
"action": "Fundoscopy and urgent neurology referral if papilloedema or visual symptoms present. MRI/MRV to exclude venous sinus thrombosis."
},
{
"id": "bd-8",
"condition": "C2/C3 Zygapophysial Joint Dysfunction",
"confidence": "uncommon",
"mimics": "Deep occipital pain — overlaps directly with semispinalis cervicis and suboccipital referral patterns",
"distinguishing_feature": "C₂–C₃ joint refers pain in patterns overlapping semispinalis cervicis TrP distribution. Joint pain has a hard end-feel on accessory movement testing; TrP pain has a soft end-feel and responds to stretch. Both can coexist.",
"action": "Assess accessory movement at C₂–C₃. Treat TrPs first; address articular component with joint mobilisation if a hard end-feel persists after TrP inactivation."
}
]
}