The Spinal Cord: Complete Guide - Anatomy, Tracts, and Clinical Correlations

ls /home/daytona/workspace/ 2>/dev/null || echo "workspace empty or missing"

mkdir -p /home/daytona/workspace/spinal-cord && python3 -c "from reportlab.lib.p…

~/spinal-cord/generate_pdf.py

from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm
from reportlab.lib.colors import HexColor, black, white
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    PageBreak, HRFlowable, KeepTogether
)
from reportlab.lib.enums import TA_LEFT, TA_CENTER, TA_JUSTIFY
from reportlab.platypus import ListFlowable, ListItem

OUTPUT = "/home/daytona/workspace/spinal-cord/Spinal_Cord_Complete_Guide.pdf"

# ── Colour palette ────────────────────────────────────────────────────────────
C_DARK_BLUE   = HexColor("#1a3a5c")
C_MID_BLUE    = HexColor("#2d6fa5")
C_LIGHT_BLUE  = HexColor("#d6e8f7")
C_ACCENT      = HexColor("#e8401c")
C_GOLD        = HexColor("#c98a1a")
C_LIGHT_GOLD  = HexColor("#fdf4e3")
C_GREEN       = HexColor("#1e7a44")
C_LIGHT_GREEN = HexColor("#e8f5ee")
C_GRAY        = HexColor("#555555")
C_LIGHT_GRAY  = HexColor("#f5f5f5")
C_TABLE_HEAD  = HexColor("#1a3a5c")
C_TABLE_ALT   = HexColor("#eaf2fb")
C_CLINICAL    = HexColor("#fff3e0")
C_CLINICAL_BD = HexColor("#e65100")

styles = getSampleStyleSheet()

def style(name, **kw):
    s = ParagraphStyle(name, **kw)
    return s

# Define all styles
TITLE = style("MyTitle",
    fontSize=26, leading=32, textColor=C_DARK_BLUE,
    fontName="Helvetica-Bold", alignment=TA_CENTER, spaceAfter=6)

SUBTITLE = style("MySubtitle",
    fontSize=12, leading=16, textColor=C_MID_BLUE,
    fontName="Helvetica", alignment=TA_CENTER, spaceAfter=4)

SOURCES = style("MySources",
    fontSize=8, leading=11, textColor=C_GRAY,
    fontName="Helvetica-Oblique", alignment=TA_CENTER, spaceAfter=2)

H1 = style("MyH1",
    fontSize=16, leading=20, textColor=white,
    fontName="Helvetica-Bold", spaceBefore=14, spaceAfter=6,
    leftIndent=0, backColor=C_DARK_BLUE,
    borderPadding=(6, 8, 6, 8))

H2 = style("MyH2",
    fontSize=13, leading=17, textColor=C_DARK_BLUE,
    fontName="Helvetica-Bold", spaceBefore=12, spaceAfter=4,
    borderPadding=(4, 0, 2, 6))

H3 = style("MyH3",
    fontSize=11, leading=15, textColor=C_MID_BLUE,
    fontName="Helvetica-Bold", spaceBefore=8, spaceAfter=3)

H4 = style("MyH4",
    fontSize=10, leading=14, textColor=C_GREEN,
    fontName="Helvetica-Bold", spaceBefore=6, spaceAfter=2)

BODY = style("MyBody",
    fontSize=9.5, leading=14, textColor=HexColor("#222222"),
    fontName="Helvetica", spaceBefore=2, spaceAfter=4,
    alignment=TA_JUSTIFY)

BULLET = style("MyBullet",
    fontSize=9.5, leading=13, textColor=HexColor("#222222"),
    fontName="Helvetica", spaceBefore=1, spaceAfter=1,
    leftIndent=14, bulletIndent=4)

CLINICAL = style("MyClinical",
    fontSize=9.5, leading=14, textColor=HexColor("#222222"),
    fontName="Helvetica", spaceBefore=3, spaceAfter=3,
    alignment=TA_JUSTIFY,
    leftIndent=10, rightIndent=10,
    backColor=C_CLINICAL,
    borderPadding=(6, 8, 6, 8))

CLINICAL_TITLE = style("MyClinicalTitle",
    fontSize=10, leading=13, textColor=C_CLINICAL_BD,
    fontName="Helvetica-Bold", spaceBefore=0, spaceAfter=2,
    leftIndent=10)

NOTE = style("MyNote",
    fontSize=9, leading=13, textColor=HexColor("#333333"),
    fontName="Helvetica-Oblique", spaceBefore=2, spaceAfter=3,
    leftIndent=16, rightIndent=8,
    backColor=C_LIGHT_GOLD,
    borderPadding=(4, 6, 4, 6))

PAGE_NUM = style("MyPageNum",
    fontSize=8, textColor=C_GRAY, fontName="Helvetica", alignment=TA_CENTER)

# ── Helper builders ───────────────────────────────────────────────────────────

def h1(text):
    return Paragraph(f"  {text}", H1)

def h2(text):
    return [
        HRFlowable(width="100%", thickness=2, color=C_DARK_BLUE, spaceAfter=2),
        Paragraph(text, H2),
    ]

def h3(text):
    return Paragraph(text, H3)

def h4(text):
    return Paragraph(text, H4)

def p(text):
    return Paragraph(text, BODY)

def sp(n=6):
    return Spacer(1, n)

def clinical(title, text):
    return KeepTogether([
        Paragraph(f"■ CLINICAL: {title}", CLINICAL_TITLE),
        Paragraph(text, CLINICAL),
        sp(4),
    ])

def note(text):
    return Paragraph(f"<i>Note: {text}</i>", NOTE)

def bullets(items):
    out = []
    for item in items:
        out.append(Paragraph(f"• {item}", BULLET))
    return out

def make_table(headers, rows, col_widths=None):
    data = [[Paragraph(f"<b>{h}</b>", style("TH",
                fontSize=8.5, leading=11, fontName="Helvetica-Bold",
                textColor=white, alignment=TA_CENTER)) for h in headers]]
    for i, row in enumerate(rows):
        bg = C_TABLE_ALT if i % 2 == 0 else white
        data.append([Paragraph(str(c), style(f"TD{i}",
                fontSize=8, leading=11, fontName="Helvetica",
                textColor=HexColor("#111111"))) for c in row])

    page_w = A4[0] - 3*cm
    if col_widths is None:
        w = page_w / len(headers)
        col_widths = [w] * len(headers)

    t = Table(data, colWidths=col_widths, repeatRows=1)
    ts = TableStyle([
        ("BACKGROUND", (0, 0), (-1, 0), C_TABLE_HEAD),
        ("ROWBACKGROUNDS", (0, 1), (-1, -1), [C_TABLE_ALT, white]),
        ("GRID", (0, 0), (-1, -1), 0.4, HexColor("#bbbbbb")),
        ("TOPPADDING", (0, 0), (-1, -1), 4),
        ("BOTTOMPADDING", (0, 0), (-1, -1), 4),
        ("LEFTPADDING", (0, 0), (-1, -1), 5),
        ("RIGHTPADDING", (0, 0), (-1, -1), 5),
        ("VALIGN", (0, 0), (-1, -1), "TOP"),
    ])
    t.setStyle(ts)
    return t

# ── Page template ─────────────────────────────────────────────────────────────
def on_first_page(canvas, doc):
    canvas.saveState()
    w, h = A4
    # header bar
    canvas.setFillColor(C_DARK_BLUE)
    canvas.rect(0, h - 1.2*cm, w, 1.2*cm, fill=1, stroke=0)
    canvas.setFillColor(white)
    canvas.setFont("Helvetica-Bold", 9)
    canvas.drawCentredString(w/2, h - 0.8*cm, "SPINAL CORD & TRACTS — COMPLETE MEDICAL REFERENCE")
    # footer
    canvas.setFillColor(C_DARK_BLUE)
    canvas.rect(0, 0, w, 0.9*cm, fill=1, stroke=0)
    canvas.setFillColor(white)
    canvas.setFont("Helvetica", 8)
    canvas.drawCentredString(w/2, 0.3*cm, "Sources: Gray's Anatomy | Localization in Clinical Neurology | Neuroanatomy through Clinical Cases | Guyton & Hall | Bradley & Daroff's Neurology")
    canvas.restoreState()

def on_later_pages(canvas, doc):
    canvas.saveState()
    w, h = A4
    canvas.setFillColor(C_DARK_BLUE)
    canvas.rect(0, h - 1.0*cm, w, 1.0*cm, fill=1, stroke=0)
    canvas.setFillColor(white)
    canvas.setFont("Helvetica-Bold", 8)
    canvas.drawCentredString(w/2, h - 0.65*cm, "SPINAL CORD & TRACTS — COMPLETE MEDICAL REFERENCE")
    canvas.setFillColor(C_DARK_BLUE)
    canvas.rect(0, 0, w, 0.8*cm, fill=1, stroke=0)
    canvas.setFillColor(white)
    canvas.setFont("Helvetica", 8)
    canvas.drawString(1.5*cm, 0.28*cm, "Orris Medical Reference")
    canvas.drawRightString(w - 1.5*cm, 0.28*cm, f"Page {doc.page}")
    canvas.restoreState()

# ── Content ───────────────────────────────────────────────────────────────────
story = []

# ── COVER ─────────────────────────────────────────────────────────────────────
story += [
    sp(60),
    Paragraph("SPINAL CORD", TITLE),
    Paragraph("Ascending, Descending &amp; Intersegmental Tracts", SUBTITLE),
    sp(8),
    HRFlowable(width="60%", thickness=3, color=C_GOLD, hAlign="CENTER"),
    sp(10),
    Paragraph("Complete Medical Reference with Clinical Correlations", SOURCES),
    sp(4),
    Paragraph("Sources: Gray's Anatomy for Students • Localization in Clinical Neurology 8e • Neuroanatomy through Clinical Cases 3e<br/>"
              "Neuroscience: Exploring the Brain 5e • Guyton &amp; Hall Medical Physiology • Bradley &amp; Daroff's Neurology in Clinical Practice<br/>"
              "Adams &amp; Victor's Principles of Neurology • Medical Physiology (Boron &amp; Boulpaep)", SOURCES),
    PageBreak(),
]

# ══════════════════════════════════════════════════════════════════════════════
# PART 1 — GROSS ANATOMY
# ══════════════════════════════════════════════════════════════════════════════
story.append(h1("PART 1: GROSS ANATOMY OF THE SPINAL CORD"))
story.append(sp(8))

story += h2("1.1 Extent and Termination")
story.append(p("The spinal cord extends from the <b>foramen magnum</b> (continuous with the medulla oblongata) inferiorly "
               "to approximately the level of the <b>disc between L1 and L2</b> in adults — though it can end as high as T12 "
               "or as low as the L2/L3 disc. In neonates it extends to ~L3 (sometimes L4). This discrepancy results from "
               "differential post-natal growth: the vertebral column grows faster than the cord."))
story.append(p("The distal end tapers into the <b>conus medullaris</b> (cone-shaped). A fine thread of connective tissue, "
               "the <b>pial filum terminale</b>, continues inferiorly. The dural sac ends at S2; beyond that, the "
               "<b>dural (coccygeal) part of the filum terminale</b> attaches to the coccyx."))
story.append(clinical("Lumbar Puncture",
    "The cord ends at L1–L2, so lumbar puncture is safely performed at L3/L4 or L4/L5 in adults. "
    "The needle enters the subarachnoid space (which extends to S2), where cauda equina roots float "
    "aside rather than being skewered. In neonates, the puncture should be at L4/L5 or L5/S1 because "
    "the cord extends lower."))

story += h2("1.2 Enlargements")
story.append(p("Two fusiform swellings correspond to limb innervation:"))
story += bullets([
    "<b>Cervical enlargement (C5–T1)</b> — contains alpha motor neurons for the upper limb; spinal nerves form the brachial plexus.",
    "<b>Lumbosacral enlargement (L1–S3)</b> — contains motor neurons for the lower limb; spinal nerves form the lumbar and sacral plexuses.",
])

story += h2("1.3 External Surface Landmarks")
story.append(make_table(
    ["Feature", "Location", "Significance"],
    [
        ["Anterior median fissure", "Deep midline anteriorly", "Anterior spinal artery runs within it"],
        ["Posterior median sulcus", "Shallow midline posteriorly", "Marks the dorsal midline"],
        ["Posterolateral sulcus (×2)", "Posterior surface, lateral", "Dorsal rootlet entry zone"],
        ["Anterolateral sulcus (×2)", "Anterior surface, lateral", "Ventral rootlet exit zone"],
        ["Posterior intermediate sulcus", "C–T levels only", "Separates fasciculus gracilis from cuneatus"],
    ],
    col_widths=[5.5*cm, 5.5*cm, 7.5*cm]
))
story.append(sp(6))

story += h2("1.4 Internal Architecture")
story.append(h3("Gray Matter (H-shaped)"))
story += bullets([
    "<b>Dorsal (posterior) horn</b> — sensory processing",
    "<b>Ventral (anterior) horn</b> — alpha and gamma motor neuron cell bodies (lower motor neurons)",
    "<b>Lateral horn</b> — present only at T1–L2 (sympathetic preganglionic) and S2–S4 (parasympathetic preganglionic)",
    "<b>Central canal</b> — ependyma-lined remnant of neural tube lumen",
])
story.append(h3("Rexed's Laminae (I – X)"))
story.append(make_table(
    ["Lamina", "Location", "Key Function / Neurons"],
    [
        ["I", "Dorsal horn tip (marginal zone)", "Pain/temperature 1st-order synapse; origin of spinothalamic tract"],
        ["II", "Substantia gelatinosa", "Pain modulation interneurons; receives C and Aδ fibers"],
        ["III–IV", "Nucleus proprius", "Touch, pressure; 2nd-order neurons for posterior pathway"],
        ["V", "Neck of dorsal horn", "Convergence of nociceptive + non-nociceptive; wide-dynamic-range neurons"],
        ["VI", "Base of dorsal horn (limb levels)", "Proprioceptive input from muscle spindles"],
        ["VII", "Intermediate zone; Clarke's col. (T1–L2)", "Origin of dorsal spinocerebellar; autonomic preganglionic neurons"],
        ["VIII", "Medial ventral horn", "Interneurons; commissural neurons"],
        ["IX", "Lateral ventral horn", "Alpha and gamma motor neurons (LMNs)"],
        ["X", "Around central canal", "Commissural neurons; visceral input"],
    ],
    col_widths=[1.6*cm, 5.5*cm, 11.4*cm]
))
story.append(sp(4))

story.append(h3("White Matter Funiculi"))
story += bullets([
    "<b>Posterior (dorsal) funiculus</b> — between dorsal median sulcus and dorsal horn",
    "<b>Lateral funiculus</b> — between dorsal and ventral horns",
    "<b>Anterior (ventral) funiculus</b> — between ventral horn and anterior median fissure",
    "<b>Anterior white commissure</b> — connects both halves; crossing zone for spinothalamic fibers",
])

# ══════════════════════════════════════════════════════════════════════════════
# PART 2 — ASCENDING TRACTS
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 2: ASCENDING TRACTS"))
story.append(sp(8))

# 2A DCML
story += h2("2A. Posterior Column – Medial Lemniscal Pathway (DCML)")
story.append(p("<b>Modalities carried:</b> Fine/discriminative touch, vibration sense, conscious proprioception (position sense, "
               "kinesthesia), two-point discrimination, stereognosis, weight perception, pressure touch."))

story.append(h3("First-Order Neuron"))
story += bullets([
    "Cell body: dorsal root ganglion (DRG) — pseudounipolar",
    "Peripheral receptors: Meissner's corpuscles, Pacinian corpuscles, muscle spindles, Golgi tendon organs",
    "Central process enters cord via <i>medial bundle</i> of dorsal root",
    "Ascends <b>ipsilaterally</b> in dorsal funiculus without synapsing in cord",
    "Collaterals enter laminae III–IV for local reflexes",
])
story.append(h3("Somatotopic Organization Within the Dorsal Funiculus"))
story += bullets([
    "<b>Fasciculus gracilis (Goll's column)</b> — medial; fibers from sacral, lumbar, lower 6 thoracic levels (T7–S5; lower limb + lower trunk)",
    "<b>Fasciculus cuneatus (Burdach's column)</b> — lateral; fibers from upper 6 thoracic and all cervical levels (C1–T6; upper limb, neck)",
    "New fibers added laterally at each level, pushing older fibers medially",
    "<b>Memory aid:</b> Legs are medial (gracilis), Arms are lateral (cuneatus)",
])
story.append(h3("Second-Order Neuron"))
story += bullets([
    "Cell body: nucleus gracilis (lower medulla) or nucleus cuneatus (upper medulla) — together = dorsal column nuclei",
    "Axons sweep anteriorly as <b>internal arcuate fibers</b> and <b>decussate</b> in the lower medulla (sensory decussation)",
    "Form the <b>medial lemniscus</b> contralaterally",
    "Ascend to <b>ventral posterior lateral (VPL) nucleus</b> of thalamus",
])
story.append(h3("Third-Order Neuron"))
story += bullets([
    "VPL thalamus → posterior limb of internal capsule (thalamic somatosensory radiations)",
    "Terminate in <b>primary somatosensory cortex</b> (postcentral gyrus, Brodmann areas 3, 1, and 2)",
])
story.append(clinical("Subacute Combined Degeneration (Vitamin B12 Deficiency)",
    "Demyelinates dorsal columns AND lateral corticospinal tracts (bilateral). Clinical features: loss of vibration "
    "and proprioception, positive Romberg's sign, broad-based sensory ataxia, spasticity. Dorsal column involvement "
    "is ipsilateral (before decussation). Peripheral neuropathy may co-exist (reducing reflexes and masking hyperreflexia)."))
story.append(clinical("Tabes Dorsalis (Neurosyphilis)",
    "Treponema pallidum destroys DRGs and posterior columns. Presents with: lightning pains, loss of proprioception "
    "(Romberg +ve), wide-based stamping gait ('stomping' — patients can't feel their feet), Argyll-Robertson pupils "
    "(accommodate but do not react to light), loss of deep tendon reflexes."))
story.append(clinical("Friedreich's Ataxia",
    "Autosomal recessive. Degeneration of dorsal columns, spinocerebellar tracts, and corticospinal tracts. "
    "Presents in adolescence with progressive limb and gait ataxia, dysarthria, loss of proprioception, "
    "areflexia, and hypertrophic cardiomyopathy (major cause of death)."))

# 2B Spinothalamic
story += h2("2B. Anterolateral (Spinothalamic) System")
story.append(p("Comprises three tracts: (i) Lateral spinothalamic, (ii) Spinoreticular, (iii) Spinomesencephalic."))

story.append(h3("i. Lateral Spinothalamic Tract (Neospinothalamic)"))
story.append(p("<b>Modalities:</b> Pain (sharp, well-localized), temperature (hot and cold)."))
story.append(h4("First-Order Neuron"))
story += bullets([
    "Cell body: DRG; peripheral receptors: free nerve endings (C-fibers for slow burning pain; Aδ for sharp fast pain)",
    "Enter cord via <i>lateral bundle</i> of dorsal root",
    "Enter <b>Lissauer's tract (dorsolateral tract)</b> — bifurcate, ascending/descending 1–2 spinal segments before entering gray matter",
    "Synapse on 2nd-order neurons in <b>lamina I</b> (marginal zone) and <b>lamina V</b> (also lamina II for C-fiber slow pain)",
])
story.append(h4("Second-Order Neuron"))
story += bullets([
    "Cell body: laminae I and V of ipsilateral dorsal horn",
    "Axons cross in the <b>anterior white commissure</b> over <b>2–3 spinal cord segments</b>",
    "<b>Clinical consequence:</b> pain/temperature loss is 2–3 dermatomes <i>below</i> the actual lesion",
    "Ascend in <b>anterolateral quadrant</b> (lateral funiculus) as the lateral spinothalamic tract",
    "Somatotopy: sacral fibers most lateral, cervical fibers most medial (S→L→T→C from outside in)",
    "Temperature fibers lie <b>dorsolaterally</b> to pain fibers within the tract",
    "Terminate in <b>VPL nucleus</b> of thalamus (also intralaminar and mediodorsal nuclei)",
])
story.append(h4("Third-Order Neuron"))
story += bullets([
    "VPL thalamus → posterior limb of internal capsule → primary somatosensory cortex (areas 3, 1, 2)",
])

story.append(h3("ii. Spinoreticular Tract (Paleospinothalamic)"))
story += bullets([
    "Origin: laminae I, V (similar to spinothalamic)",
    "Ascends <b>bilaterally</b> (does not cross completely)",
    "Terminates in <b>medullary and pontine reticular formation</b>, then relays to <b>intralaminar thalamic nuclei</b> (centromedian nucleus)",
    "Function: <b>emotional and arousal aspects of pain</b> — the 'suffering' pathway. Active in chronic pain states.",
])

story.append(h3("iii. Spinomesencephalic Tract"))
story += bullets([
    "Origin: dorsal horn",
    "Terminates in <b>periaqueductal gray (PAG)</b> and <b>superior colliculi</b>",
    "Function: <b>central modulation of pain</b>. The PAG is rich in opioid receptors; its stimulation produces profound analgesia.",
    "This is the primary site of action of morphine and endogenous opioids (enkephalins, endorphins).",
])
story.append(clinical("Anterolateral Cordotomy",
    "Surgical or percutaneous section of the lateral spinothalamic tract to relieve intractable cancer pain. "
    "Produces contralateral pain and temperature loss beginning 2–3 segments below the cordotomy level. "
    "Does NOT affect touch, vibration, or proprioception (dorsal columns intact)."))
story.append(clinical("Syringomyelia — Early Presentation",
    "A central cord cavity (syrinx) first destroys the anterior white commissure, interrupting decussating spinothalamic fibers. "
    "Produces bilateral, 'cape-like' or 'vest-like' loss of pain and temperature at involved segments (neck, shoulders, arms) "
    "with PRESERVED touch, vibration, and proprioception (dorsal columns uninvolved) — called dissociated sensory loss. "
    "Painless burns on hands are a classic early clue."))
story.append(clinical("Herpes Zoster (Shingles)",
    "Varicella-zoster virus reactivates in the DRG (first-order neuron cell bodies). Pain and vesicular rash follow a dermatomal "
    "distribution. Motor function is typically preserved because the DRG is purely sensory. Zoster motor neuropathy is rare. "
    "Post-herpetic neuralgia (persistent burning pain) results from central sensitization."))

# 2C Spinocerebellar
story += h2("2C. Spinocerebellar Tracts (Unconscious Proprioception)")
story.append(p("These tracts convey unconscious proprioceptive information from muscles and joints to the cerebellum for coordination."))

story.append(h3("Dorsal (Posterior) Spinocerebellar Tract (DSCT)"))
story += bullets([
    "<b>Origin:</b> Clarke's nucleus (nucleus thoracicus, lamina VII) at T1–L2/L3",
    "<b>Input:</b> Ia afferents (muscle spindles) and Ib afferents (Golgi tendon organs) via 1st-order DRG neurons",
    "<b>Course:</b> Ascends <b>ipsilaterally</b> in dorsal part of lateral funiculus (peripheral portion)",
    "<b>Entry to cerebellum:</b> Inferior cerebellar peduncle (restiform body)",
    "<b>Termination:</b> Ipsilateral cerebellar cortex (vermis, anterior lobe)",
    "Carries information from lower half of body and trunk",
    "No relay — Clarke's nucleus neurons project directly (very fast conduction)",
    "Sacral/lower lumbar proprioception first ascends in posterior columns to reach Clarke's nucleus at L2",
])

story.append(h3("Ventral (Anterior) Spinocerebellar Tract (VSCT)"))
story += bullets([
    "<b>Origin:</b> Laminae V–VII (border cells) of lumbosacral enlargement",
    "<b>Course:</b> Crosses to <b>contralateral</b> lateral funiculus (anterior part), ascends through entire cord and brainstem",
    "<b>Entry to cerebellum:</b> Superior cerebellar peduncle; then <b>re-crosses</b> within cerebellum",
    "Net result: information reaches <b>ipsilateral</b> cerebellar hemisphere (double crossing)",
    "Carries info about state of the spinal interneuronal circuitry — important for locomotion",
])

story.append(h3("Cuneocerebellar Tract"))
story += bullets([
    "<b>Origin:</b> Accessory (external) cuneate nucleus, medulla (receives fibers from C1–T6)",
    "Functional equivalent of DSCT for upper limb and neck",
    "<b>Entry:</b> Inferior cerebellar peduncle",
])

story.append(h3("Rostral Spinocerebellar Tract"))
story += bullets([
    "Equivalent of VSCT for upper limb",
    "Ascends mostly ipsilaterally",
    "Enters via inferior or superior cerebellar peduncle",
])
story.append(clinical("Spinocerebellar Ataxias (SCAs)",
    "Hereditary SCAs (e.g., SCA1, SCA2, SCA3/Machado-Joseph disease) degenerate spinocerebellar tracts and cerebellar cortex. "
    "Clinical features: gait ataxia, limb ataxia (dysmetria, dysdiadochokinesia), intention tremor, nystagmus, dysarthria. "
    "DSCT lesions cause ipsilateral ataxia. Friedreich's ataxia additionally involves dorsal columns and corticospinal tracts."))

# 2D Minor tracts
story += h2("2D. Other Ascending Tracts")
story.append(make_table(
    ["Tract", "Origin", "Termination", "Function"],
    [
        ["Spinotectal", "Dorsal horn", "Superior colliculus (tectum)", "Spinovisual reflexes — turning head/eyes to noxious stimuli"],
        ["Spino-olivary", "Dorsal and ventral horn", "Inferior olivary nucleus → cerebellum", "Cutaneous + proprioceptive info for cerebellar modulation"],
        ["Spinovestibular", "Cervical cord", "Vestibular nuclei", "Neck proprioception integrated with vestibular information"],
        ["Spinohypothalamic", "Dorsal horn", "Hypothalamus", "Autonomic (CV, endocrine) responses to pain"],
    ],
    col_widths=[4.5*cm, 4.0*cm, 5.5*cm, 4.5*cm]
))
story.append(sp(4))

# ══════════════════════════════════════════════════════════════════════════════
# PART 3 — DESCENDING TRACTS
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 3: DESCENDING TRACTS"))
story.append(sp(8))
story.append(p("Descending tracts are divided into <b>lateral pathways</b> (voluntary fine motor control — corticospinal, rubrospinal) "
               "and <b>ventromedial pathways</b> (postural control and locomotion — reticulospinal, vestibulospinal, tectospinal). "
               "The lateral pathways are under direct cortical control; the ventromedial pathways are under brainstem control."))

# 3A Corticospinal
story += h2("3A. Corticospinal Tract (Pyramidal Tract)")
story.append(p("The most important and longest descending tract in the CNS. Contains ~<b>1 million axons</b> per side."))

story.append(h3("Origin (Cortical Areas)"))
story += bullets([
    "<b>60–70%</b> from Brodmann areas <b>4</b> (primary motor cortex, precentral gyrus) and <b>6</b> (premotor and supplementary motor cortex)",
    "<b>30–40%</b> from parietal lobe: areas 3, 1, 2 (somatosensory cortex), area 5 (superior parietal lobule), cingulate gyrus",
    "Giant <b>Betz cells</b> of area 4 produce the largest-diameter, fastest-conducting axons",
])

story.append(h3("Course"))
story += bullets([
    "<b>Corona radiata</b> — convergence in cerebral white matter",
    "<b>Posterior limb of internal capsule</b> — arm fibers anterolateral, leg fibers posteromedial",
    "<b>Crus cerebri (cerebral peduncle)</b> — middle 3/5ths of midbrain",
    "<b>Anterior pons</b> — scattered as small bundles (disrupted by transverse pontocerebellar fibers)",
    "<b>Medullary pyramid</b> — re-grouped as bilateral ventral swellings on medullary surface",
    "<b>Pyramidal decussation</b> (caudal medulla): ~90% cross → <b>lateral corticospinal tract (LCST)</b> in lateral funiculus",
    "Remaining ~10% do NOT cross → <b>anterior (ventral) corticospinal tract (ACST)</b> in anterior funiculus; cross later via ventral commissure at each cervical/upper thoracic level",
])

story.append(h3("Somatotopy of LCST in the Cord"))
story += bullets([
    "Cervical fibers most dorsomedial; sacral fibers most ventrolateral",
    "New fibers added ventrally as the tract descends; old fibers pushed dorsally",
    "Clinically: <b>extrinsic cord compression</b> (peripheral) first affects leg fibers (lateral); <b>intramedullary</b> lesions first affect arm fibers (central)",
])

story.append(h3("Termination"))
story += bullets([
    "LCST: laminae IV–VII (via interneurons) and directly on lamina IX (alpha motor neurons) — monosynaptic for fine hand movements",
    "ACST: lamina III of cervical and upper thoracic cord — mainly axial/proximal muscles",
    "Medial motor column (axial muscles): mainly receives ventromedial pathway input",
    "Lateral motor column (distal limb muscles): heavy direct corticospinal input → voluntary fine finger movements",
])
story.append(clinical("Upper Motor Neuron (UMN) Syndrome",
    "LCST lesion at any level: spastic paralysis (increased tone, hyper-reflexia, clonus), positive Babinski sign "
    "(extensor plantar response — great toe dorsiflexes, other toes fan out), loss of superficial abdominal reflexes. "
    "Babinski is the single most important UMN sign; it is the normal response in infants before LCST myelinates."))
story.append(clinical("Internal Capsule Stroke",
    "Lateral striate artery occlusion → infarction in the posterior limb of internal capsule. Produces contralateral hemiplegia "
    "(face, arm, leg equally) WITHOUT cortical signs (no aphasia, no cortical sensory loss) — 'pure motor hemiplegia.' "
    "The LCST is the tightest choke-point in the motor system."))
story.append(clinical("Amyotrophic Lateral Sclerosis (ALS)",
    "Destroys BOTH UMNs (corticospinal) and LMNs (anterior horn cells). Combined UMN signs (spasticity, hyperreflexia) "
    "AND LMN signs (fasciculations, atrophy, hyporeflexia) at the same time. Co-occurrence is clinically diagnostic of ALS."))
story.append(clinical("Spinal Shock",
    "Immediately after acute cord transection: flaccid paralysis WITH absent reflexes (areflexia) below the lesion — paradoxically "
    "resembles LMN syndrome despite upper cord lesion. Caused by sudden loss of facilitatory brain input. After weeks to months, "
    "UMN pattern emerges: spasticity, hyperreflexia, Babinski sign."))

# 3B Rubrospinal
story += h2("3B. Rubrospinal Tract")
story += bullets([
    "<b>Origin:</b> Red nucleus (magnocellular part, midbrain tegmentum) — receives input from cortex and dentate nucleus",
    "Immediately decussates in <b>ventral tegmentum</b> (ventral tegmental decussation)",
    "Descends in <b>lateral funiculus</b>, just anterior to LCST",
    "Terminates mainly in <b>cervical cord</b> levels (laminae V–VII)",
    "Function: voluntary control of distal limb movements, especially arm; supplements and partially compensates for LCST damage",
    "In humans, this tract is relatively small (may be partially vestigial compared to animals)",
])

# 3C Vestibulospinal
story += h2("3C. Vestibulospinal Tracts")
story.append(h3("Lateral Vestibulospinal Tract (LVST)"))
story += bullets([
    "<b>Origin:</b> Lateral (Deiters') vestibular nucleus",
    "Descends <b>ipsilaterally</b> in anterior/ventrolateral funiculus; extends to all cord levels",
    "Function: <b>strongly FACILITATES extensor</b> motor neurons and inhibits flexors → facilitates antigravity posture",
])
story.append(h3("Medial Vestibulospinal Tract (MVST)"))
story += bullets([
    "<b>Origin:</b> Medial vestibular nucleus (bilateral contributions)",
    "Descends within the <b>medial longitudinal fasciculus (MLF)</b> — reaches cervical cord only",
    "Function: coordinates head and neck with vestibular signals; reflexive head-righting responses",
])
story.append(clinical("Decerebrate vs. Decorticate Posturing",
    "Decerebrate (lesion between red nucleus and vestibular nuclei, midbrain/pons): vestibulospinal "
    "tract intact but rubrospinal/corticospinal inhibition gone → extension of all four limbs, arching of back. "
    "Decorticate (lesion above red nucleus): rubrospinal inhibition also removed → arm flexion, leg extension. "
    "Decerebrate indicates deeper, more severe brainstem damage."))

# 3D Reticulospinal
story += h2("3D. Reticulospinal Tracts")
story.append(h3("Pontine (Medial) Reticulospinal Tract"))
story += bullets([
    "<b>Origin:</b> Pontine reticular formation (nucleus reticularis pontis oralis et caudalis)",
    "Descends <b>ipsilaterally</b> in anterior funiculus",
    "Function: <b>FACILITATES</b> axial and proximal extensor motor neurons; supports antigravity posture; modulates muscle tone",
])
story.append(h3("Medullary (Lateral) Reticulospinal Tract"))
story += bullets([
    "<b>Origin:</b> Medullary reticular formation (nucleus gigantocellularis); receives cortical input",
    "Descends <b>bilaterally</b> in lateral funiculus",
    "Function: <b>INHIBITS</b> extensor motor neurons; facilitates flexors. Cortical lesions disinhibit extensor posture.",
    "Also mediates <b>descending inhibitory control of pain</b> via serotonin and noradrenaline pathways",
])
story.append(clinical("Central Pain Modulation (Descending Inhibition)",
    "The medullary reticulospinal system is part of the descending pain inhibitory pathway. "
    "Activation: cortex → PAG → nucleus raphe magnus → dorsal horn (laminae I, II, V). "
    "Opioids act primarily at the PAG. SNRIs (duloxetine, venlafaxine) and TCAs enhance noradrenergic inhibition. "
    "Disruption of this system is implicated in fibromyalgia, chronic widespread pain, and central sensitization syndromes."))

# 3E Tectospinal
story += h2("3E. Tectospinal Tract")
story += bullets([
    "<b>Origin:</b> Superior colliculus (tectum of midbrain)",
    "Immediately crosses in <b>dorsal tegmentum</b> (dorsal tegmental decussation)",
    "Descends in anterior funiculus, medial to ACST; extends only to <b>upper cervical cord (C4)</b>",
    "Function: reflexive turning of head and neck in response to sudden visual or auditory stimuli; coordinates head orientation with gaze",
])

# ══════════════════════════════════════════════════════════════════════════════
# PART 4 — INTERSEGMENTAL TRACTS
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 4: INTERSEGMENTAL (PROPRIOSPINAL) TRACTS"))
story.append(sp(8))
story.append(p("Intersegmental (propriospinal) tracts are intrinsic to the spinal cord and connect different segmental levels. "
               "They are also called the <b>fasciculus proprius</b> and form a collar of short ascending and descending fibers "
               "immediately adjacent to the gray matter in all three funiculi."))

story += h2("4.1 Fasciculus Proprius")
story += bullets([
    "Lies immediately adjacent to the gray matter in <i>all</i> three funiculi (posterior, lateral, anterior)",
    "Neurons originate from laminae V, VI, VII, and VIII",
    "Spans multiple cord segments — some fibers travel only 1–2 segments, others may span the entire cord length",
    "Function: coordinate motor activity across multiple cord levels (inter-limb coordination during locomotion, sequential muscle group activation)",
])

story += h2("4.2 Lissauer's Tract (Posterolateral Tract / Dorsolateral Fasciculus)")
story += bullets([
    "Located in the <b>posterolateral funiculus</b>, just lateral to the dorsal horn tip",
    "Contains finely myelinated (Aδ) and unmyelinated (C) fibers from dorsal roots",
    "Fibers bifurcate on entering and ascend/descend <b>1–2 spinal segments</b> before synapsing in dorsal horn laminae I and II",
    "Contains both primary afferent collaterals AND short propriospinal fibers",
    "Function: allows pain signals to spread over several segments before entering the spinothalamic relay; contributes to dermatomal overlap of pain",
])
story.append(clinical("Pain Referral and Dermatome Overlap",
    "Because Lissauer's tract fibers spread over 2 segments before synapsing, pain from a single spinal nerve root "
    "routinely overlaps adjacent dermatomes. A single DRG lesion typically produces analgesia extending 1–2 levels in each direction. "
    "This is why single-root compressive radiculopathy produces pain across a wide dermatomal band, not a sharp single-segment line."))

story += h2("4.3 Interfascicular Fasciculus (Comma Tract of Schultze)")
story += bullets([
    "Located within the <b>fasciculus cuneatus</b> (dorsal funiculus) at cervical/upper thoracic levels",
    "Contains descending fibers from rostral cord levels (axon collaterals from dorsal column fibers)",
    "Relays proprioceptive information back down to lower cord segments",
])

story += h2("4.4 Septomarginal Fasciculus (Oval Bundle of Flechsig)")
story += bullets([
    "Located within the <b>fasciculus gracilis</b> (medial dorsal funiculus) at lower thoracic/sacral regions",
    "Contains both ascending and descending short-range propriospinal fibers",
])

story += h2("4.5 Medial Longitudinal Fasciculus (MLF)")
story += bullets([
    "Runs from the midbrain through the brainstem to <b>upper cervical cord</b>",
    "In the cord, located in the <b>anterior funiculus medially</b> (sulcomarginal fasciculus)",
    "Contains the medial vestibulospinal tract and tectospinal fibers",
    "Critical for coordinating head, neck, and eye movements",
])
story.append(clinical("Internuclear Ophthalmoplegia (INO) — MLF Syndrome",
    "In the brainstem, the MLF connects the CN VI nucleus (pons) to the contralateral CN III nucleus (midbrain) for conjugate lateral gaze. "
    "Demyelination (MS) or ischemia of the MLF causes INO: failure of adduction of the ipsilateral eye on lateral gaze, "
    "with nystagmus of the abducting contralateral eye. Bilateral INO in a young person = MS until proven otherwise."))

# ══════════════════════════════════════════════════════════════════════════════
# PART 5 — VASCULATURE
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 5: VASCULATURE AND CLINICAL IMPLICATIONS"))
story.append(sp(8))

story += h2("5.1 Anterior Spinal Artery (ASA)")
story += bullets([
    "Single vessel running in the anterior median fissure",
    "Formed by contributions from both vertebral arteries at the cervicomedullary junction",
    "Reinforced by <b>8–10 anterior medullary (radicular) arteries</b> along its course",
    "<b>Artery of Adamkiewicz (arteria radicularis magna)</b> — the most important reinforcing vessel; arises from T9–T12 (left side in ~75%)",
    "Supplies the <b>anterior 2/3 of the cord</b>: anterior horn cells, anterior and lateral funiculi (spinothalamic tract AND corticospinal tract)",
])
story.append(clinical("Anterior Cord Syndrome (ASA Occlusion)",
    "Occurs in aortic surgery (cross-clamping), atherosclerosis, dissection, or severe flexion injury. "
    "Features: bilateral paralysis below lesion (corticospinal + anterior horn), bilateral loss of pain and temperature "
    "(spinothalamic), but PRESERVED vibration, proprioception, and fine touch (posterior columns intact — supplied by PSA). "
    "Worst prognosis of all incomplete cord syndromes."))

story += h2("5.2 Posterior Spinal Arteries (PSA)")
story += bullets([
    "Two paired vessels running along the posterolateral surface",
    "Reinforced by posterior medullary arteries",
    "Supply the <b>posterior 1/3 of the cord</b>: posterior horn, dorsal columns, posterior funiculi",
])
story.append(clinical("Posterior Cord Syndrome (PSA Occlusion)",
    "Rare. Isolated loss of vibration, proprioception, and fine touch (dorsal column modalities). "
    "Motor function and pain/temperature completely preserved. Clinically: sensory ataxia, positive Romberg."))

# ══════════════════════════════════════════════════════════════════════════════
# PART 6 — CLINICAL SYNDROMES
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 6: CLINICAL SPINAL CORD SYNDROMES"))
story.append(sp(8))

story += h2("6A. Complete Cord Transection")
story.append(p("All motor and sensory functions lost below the lesion (both sides). Initial <b>spinal shock</b> (flaccid paralysis, areflexia) → "
               "weeks/months later: UMN syndrome (spasticity, hyperreflexia, Babinski). "
               "Bladder/bowel: urinary retention initially → later reflex incontinence."))

story += h2("6B. Brown-Séquard Syndrome (Hemisection)")
story.append(p("Unilateral cord lesion: stab wound, herniated cervical disc, tumor, multiple sclerosis. Accounts for 1–4% of traumatic SCIs. "
               "<b>Best prognosis</b> for functional recovery. Most subjects regain bowel and bladder continence."))
story.append(make_table(
    ["Feature", "Side", "Level"],
    [
        ["Spastic paralysis (UMN — LCST)", "IPSILATERAL", "Below lesion"],
        ["Loss of fine touch, vibration, proprioception (DCML)", "IPSILATERAL", "Below lesion"],
        ["Loss of pain and temperature (spinothalamic)", "CONTRALATERAL", "2–3 segments below lesion"],
        ["LMN weakness + atrophy (anterior horn)", "IPSILATERAL", "AT lesion level"],
        ["Horner's syndrome (ciliospinal center)", "IPSILATERAL", "If C8–T2 lesion"],
    ],
    col_widths=[8.0*cm, 4.5*cm, 6.0*cm]
))
story.append(sp(4))
story.append(note("Memory aid: 'Motor same, pain opposite' — ipsilateral motor loss (LCST decussated above at medulla); contralateral pain loss (spinothalamic crossed in cord)."))
story.append(sp(4))

story += h2("6C. Central Cord Syndrome")
story.append(p("Most common incomplete SCI (~50%). Mechanism: hyperextension in elderly with cervical spondylosis, syringomyelia, intramedullary tumor. "
               "Because LCST leg fibers are lateral and cervical fibers are medial, central damage hits arm fibers first."))
story.append(p("<b>Mnemonic — 'MUD':</b>"))
story += bullets([
    "<b>M</b>otor > sensory deficit",
    "<b>U</b>pper > lower limb weakness (arms worse than legs)",
    "<b>D</b>istal > proximal (hands affected most)",
])
story += bullets([
    "Bladder dysfunction (usually urinary retention)",
    "Burning dysesthetic pain in the arms",
    "Variable sensory loss below lesion",
])

story += h2("6D. Anterior Cord Syndrome")
story += bullets([
    "Cause: ASA occlusion (aortic surgery, severe flexion injury)",
    "Bilateral loss of motor function (paraplegia/tetraplegia)",
    "Bilateral loss of pain and temperature",
    "PRESERVED dorsal column modalities (touch, vibration, proprioception)",
    "<b>Worst prognosis</b> of the incomplete syndromes",
])

story += h2("6E. Posterior Cord Syndrome")
story += bullets([
    "PSA occlusion (rare)",
    "Bilateral loss of vibration, proprioception, fine touch",
    "Motor function and pain/temperature preserved",
    "Sensory ataxia, Romberg positive",
])

story += h2("6F. Conus Medullaris Syndrome")
story += bullets([
    "Lesion at L1–L2 (conus) — mixed UMN and LMN signs",
    "Saddle anesthesia (S3–S5: inner thighs, perineum, perianal area)",
    "Areflexic/atonic bladder, bowel dysfunction, sexual dysfunction",
    "Relatively preserved lower limb strength (lumbar anterior horn cells may be spared)",
])

story += h2("6G. Cauda Equina Syndrome")
story += bullets([
    "NOT a cord syndrome — compression of L2–S5 nerve roots below L1/L2",
    "Causes: central disc herniation, tumor, epidural hematoma/abscess",
    "<b>Pure LMN signs</b>: flaccid weakness, areflexia, muscle atrophy",
    "Saddle anesthesia, bladder/bowel dysfunction (urinary retention → overflow incontinence)",
    "Asymmetric and patchy — individual roots affected selectively",
    "<b>Surgical emergency</b> — decompression within 24–48 hours to preserve bladder/bowel function",
])
story.append(note("Cauda Equina vs. Conus: Cauda equina = pure LMN (flaccid), sacral reflexes absent; Conus = mixed UMN/LMN, saddle anesthesia with variable reflexes."))
story.append(sp(4))

story += h2("6H. Syringomyelia — Full Progression")
story += bullets([
    "<b>Association:</b> Chiari malformation type I (most common), spinal cord trauma, intramedullary tumor, arachnoiditis",
    "<b>Stage 1 (central):</b> Anterior white commissure destroyed → bilateral cape-like dissociated sensory loss (pain/temp lost, touch/vibration preserved)",
    "<b>Stage 2 (ventral horn):</b> LMN weakness, atrophy, areflexia at lesion level (hands, arms)",
    "<b>Stage 3 (lateral column):</b> LCST involvement → spastic paraparesis below syrinx",
    "<b>Stage 4 (Horner's):</b> C8–T2 involvement → ipsilateral Horner's syndrome (miosis, ptosis, anhidrosis)",
    "<b>Stage 5 (dorsal column):</b> Loss of proprioception and vibration",
    "Painless burns on hands are a classic early presenting feature",
])

story += h2("6I. Subacute Combined Degeneration")
story += bullets([
    "Vitamin B12 (or copper) deficiency; myelination failure",
    "Dorsal columns + lateral corticospinal tracts (bilateral) — the 'combined' refers to both column types",
    "Loss of vibration + proprioception (dorsal columns), spasticity + hyperreflexia (corticospinal)",
    "Positive Romberg, broad-based gait; cognitive changes may co-exist",
    "Peripheral neuropathy (reducing reflexes) can mask hyperreflexia",
    "Treatment: intramuscular vitamin B12 (hydroxocobalamin); neurological recovery depends on duration",
])

story += h2("6J. Autonomic Dysreflexia")
story += bullets([
    "Occurs in SCI above <b>T6</b> (above major splanchnic sympathetic outflow)",
    "Trigger: noxious stimulus below lesion (full bladder, bowel impaction, pressure sore, tight clothing)",
    "Pathophysiology: massive uncontrolled sympathetic discharge below lesion without supraspinal inhibition",
    "<b>Life-threatening hypertension</b> (BP may reach 300 mmHg systolic), bradycardia (baroreceptor reflex), "
    "sweating/flushing ABOVE lesion, pallor/piloerection BELOW lesion",
    "Treatment: sit patient upright (orthostatic drop), identify and remove trigger, sublingual nifedipine or GTN",
])

# ══════════════════════════════════════════════════════════════════════════════
# PART 7 — MASTER SUMMARY TABLE
# ══════════════════════════════════════════════════════════════════════════════
story.append(PageBreak())
story.append(h1("PART 7: MASTER SUMMARY TABLE OF ALL TRACTS"))
story.append(sp(8))

story.append(make_table(
    ["Tract", "Type", "Funiculus", "Origin", "Decussation", "Termination", "Function"],
    [
        ["Fasciculus gracilis", "Asc.", "Post. (medial)", "DRG T7–S5", "Medulla", "VPL thalamus → cortex", "Vibration, proprioception, fine touch (lower body)"],
        ["Fasciculus cuneatus", "Asc.", "Post. (lateral)", "DRG C1–T6", "Medulla", "VPL thalamus → cortex", "Vibration, proprioception, fine touch (upper body)"],
        ["Lat. spinothalamic", "Asc.", "Lateral", "Laminae I, V", "Ant. commissure (2–3 seg. below)", "VPL thalamus → cortex", "Pain, temperature"],
        ["Ant. spinothalamic", "Asc.", "Anterior", "Laminae VI, VII", "Ant. commissure", "VPL thalamus", "Crude touch"],
        ["Spinoreticular", "Asc.", "Lateral", "Laminae I, V", "Bilateral", "Reticular formation", "Emotional pain, arousal"],
        ["Spinomesencephalic", "Asc.", "Lateral", "Dorsal horn", "Bilateral", "PAG, sup. colliculus", "Pain modulation, visual reflexes"],
        ["Dorsal spinocerebellar", "Asc.", "Lat. (dorsal)", "Clarke's nucleus T1–L2", "None (ipsilateral)", "Cerebellum (inf. ped.)", "Unconscious proprioception (lower body)"],
        ["Ventral spinocerebellar", "Asc.", "Lat. (ventral)", "Laminae V–VII", "Contralateral; re-crosses", "Cerebellum (sup. ped.)", "Unconscious proprioception (lower body)"],
        ["Spinotectal", "Asc.", "Lateral", "Dorsal horn", "Contralateral", "Superior colliculus", "Spinovisual reflexes"],
        ["Lat. corticospinal (LCST)", "Desc.", "Lateral", "Motor cortex (areas 4, 6)", "Pyramidal decussation (medulla)", "Laminae IV–VII, IX", "Voluntary movement (contralateral)"],
        ["Ant. corticospinal (ACST)", "Desc.", "Anterior", "Motor cortex", "Ventral commissure (segmental)", "Lamina III (cervical)", "Axial/proximal voluntary (bilateral)"],
        ["Rubrospinal", "Desc.", "Lateral", "Red nucleus", "Ventral tegmentum (midbrain)", "Laminae V–VII (cervical)", "Distal limb movements, arm control"],
        ["Lat. vestibulospinal", "Desc.", "Ant./ventrolateral", "Lateral vest. nucleus", "None (ipsilateral)", "All levels, laminae VII–IX", "Extensor facilitation, balance"],
        ["Med. vestibulospinal", "Desc.", "Anterior (MLF)", "Medial vest. nucleus", "Bilateral", "Cervical cord only", "Head and neck reflexes"],
        ["Med. reticulospinal", "Desc.", "Lateral", "Medullary reticular form.", "Bilateral", "All levels", "Inhibits extensors, pain modulation"],
        ["Pont. reticulospinal", "Desc.", "Anterior", "Pontine reticular form.", "Ipsilateral", "All levels", "Facilitates extensors, axial tone"],
        ["Tectospinal", "Desc.", "Anterior", "Superior colliculus", "Dorsal tegmentum", "Upper cervical only", "Head orientation to stimuli"],
        ["Fasciculus proprius", "Interseg.", "All funiculi", "Laminae V–VIII", "Both sides", "Multiple cord levels", "Inter-segmental coordination"],
        ["Lissauer's tract", "Interseg.", "Posterolateral", "DRG (Aδ, C fibers)", "None", "1–2 segments up/down", "Pain signal dispersion, dermatomal overlap"],
        ["MLF (in cord)", "Interseg.", "Anterior (medial)", "Vestibular nuclei / tectum", "Bilateral", "Cervical cord", "Head/neck/eye coordination"],
    ],
    col_widths=[3.5*cm, 1.4*cm, 2.5*cm, 3.2*cm, 3.0*cm, 3.2*cm, 4.7*cm]
))
story.append(sp(10))

# end note
story.append(HRFlowable(width="100%", thickness=1, color=C_MID_BLUE))
story.append(sp(4))
story.append(Paragraph("Compiled by Orris Medical AI • Sources: Gray's Anatomy for Students | Localization in Clinical Neurology 8e | "
                        "Neuroanatomy through Clinical Cases 3e | Neuroscience: Exploring the Brain 5e | Guyton &amp; Hall Medical Physiology | "
                        "Bradley &amp; Daroff's Neurology in Clinical Practice | Adams &amp; Victor's Principles of Neurology", SOURCES))

# ── Build ─────────────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=1.8*cm, rightMargin=1.8*cm,
    topMargin=1.6*cm, bottomMargin=1.5*cm,
    title="Spinal Cord & Tracts — Complete Medical Reference",
    author="Orris Medical AI",
    subject="Neuroanatomy",
)
doc.build(story, onFirstPage=on_first_page, onLaterPages=on_later_pages)
print(f"PDF generated: {OUTPUT}")

cd /home/daytona/workspace/spinal-cord && python3 generate_pdf.py 2>&1

ls -lh /home/daytona/workspace/spinal-cord/Spinal_Cord_Complete_Guide.pdf

mkdir -p /home/daytona/workspace/spinal-cord/images && cd /home/daytona/workspac…

ls -lh /home/daytona/workspace/spinal-cord/images/ 2>/dev/null && echo "---" && …

ls -lh /home/daytona/workspace/spinal-cord/images/