mkdir -p /home/daytona/workspace/spinal-cord-pdf && ls /home/daytona/workspace/s…

~/spinal-cord-pdf/generate_pdf.py

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

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

# Colors
DARK_BLUE = HexColor("#1a3a5c")
MED_BLUE = HexColor("#2e6da4")
LIGHT_BLUE = HexColor("#dce8f5")
ACCENT_RED = HexColor("#c0392b")
ACCENT_GREEN = HexColor("#1a7a4a")
ACCENT_ORANGE = HexColor("#d35400")
LIGHT_GRAY = HexColor("#f5f5f5")
DARK_GRAY = HexColor("#333333")
MED_GRAY = HexColor("#666666")
CLINICAL_BG = HexColor("#fff3cd")
CLINICAL_BORDER = HexColor("#e6a817")
TABLE_HEADER = HexColor("#2e6da4")
TABLE_ALT = HexColor("#eaf2fb")

styles = getSampleStyleSheet()

def make_styles():
    s = {}
    s['title'] = ParagraphStyle('title', fontName='Helvetica-Bold', fontSize=28,
        textColor=white, spaceAfter=4, alignment=TA_CENTER, leading=34)
    s['subtitle'] = ParagraphStyle('subtitle', fontName='Helvetica', fontSize=14,
        textColor=HexColor("#cce0ff"), spaceAfter=2, alignment=TA_CENTER, leading=18)
    s['h1'] = ParagraphStyle('h1', fontName='Helvetica-Bold', fontSize=18,
        textColor=white, spaceBefore=8, spaceAfter=4, leading=22,
        backColor=DARK_BLUE, leftIndent=-12, rightIndent=-12, borderPadding=(6,12,6,12))
    s['h2'] = ParagraphStyle('h2', fontName='Helvetica-Bold', fontSize=14,
        textColor=DARK_BLUE, spaceBefore=10, spaceAfter=4, leading=18,
        borderPadding=(4,0,2,0))
    s['h3'] = ParagraphStyle('h3', fontName='Helvetica-Bold', fontSize=12,
        textColor=MED_BLUE, spaceBefore=8, spaceAfter=3, leading=16)
    s['h4'] = ParagraphStyle('h4', fontName='Helvetica-BoldOblique', fontSize=11,
        textColor=ACCENT_ORANGE, spaceBefore=6, spaceAfter=2, leading=14)
    s['body'] = ParagraphStyle('body', fontName='Helvetica', fontSize=10,
        textColor=DARK_GRAY, spaceBefore=3, spaceAfter=3, leading=15,
        alignment=TA_JUSTIFY)
    s['bullet'] = ParagraphStyle('bullet', fontName='Helvetica', fontSize=10,
        textColor=DARK_GRAY, spaceBefore=2, spaceAfter=2, leading=14,
        leftIndent=16, bulletIndent=4)
    s['clinical'] = ParagraphStyle('clinical', fontName='Helvetica', fontSize=10,
        textColor=HexColor("#5a3e00"), spaceBefore=3, spaceAfter=3, leading=14,
        alignment=TA_JUSTIFY)
    s['clinical_title'] = ParagraphStyle('clinical_title', fontName='Helvetica-Bold',
        fontSize=11, textColor=HexColor("#c0392b"), spaceBefore=2, spaceAfter=2, leading=14)
    s['note'] = ParagraphStyle('note', fontName='Helvetica-Oblique', fontSize=9.5,
        textColor=MED_GRAY, spaceBefore=2, spaceAfter=2, leading=13,
        leftIndent=10)
    s['toc_entry'] = ParagraphStyle('toc_entry', fontName='Helvetica', fontSize=10.5,
        textColor=DARK_BLUE, spaceBefore=3, spaceAfter=3, leading=14, leftIndent=10)
    s['toc_sub'] = ParagraphStyle('toc_sub', fontName='Helvetica', fontSize=9.5,
        textColor=MED_GRAY, spaceBefore=1, spaceAfter=1, leading=12, leftIndent=24)
    return s

S = make_styles()

def clinical_box(title, lines, s):
    """Returns a list of flowables forming a clinical note box."""
    content = []
    rows = [[Paragraph(f"⚠  CLINICAL CORRELATE: {title}", s['clinical_title'])]]
    for line in lines:
        rows.append([Paragraph(line, s['clinical'])])
    t = Table(rows, colWidths=[165*mm])
    t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), CLINICAL_BG),
        ('BACKGROUND', (0,1), (-1,-1), HexColor("#fffdf0")),
        ('LINEABOVE', (0,0), (-1,0), 2, CLINICAL_BORDER),
        ('LINEBELOW', (0,-1), (-1,-1), 2, CLINICAL_BORDER),
        ('LINEBEFORE', (0,0), (0,-1), 3, CLINICAL_BORDER),
        ('LINEAFTER', (-1,0), (-1,-1), 1, HexColor("#f0d080")),
        ('TOPPADDING', (0,0), (-1,-1), 5),
        ('BOTTOMPADDING', (0,0), (-1,-1), 5),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 8),
    ]))
    content.append(Spacer(1, 4))
    content.append(t)
    content.append(Spacer(1, 4))
    return content

def section_header(text, s):
    t = Table([[Paragraph(text, s['h1'])]], colWidths=[165*mm])
    t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), DARK_BLUE),
        ('TOPPADDING', (0,0), (-1,-1), 8),
        ('BOTTOMPADDING', (0,0), (-1,-1), 8),
        ('LEFTPADDING', (0,0), (-1,-1), 12),
        ('RIGHTPADDING', (0,0), (-1,-1), 12),
    ]))
    return [Spacer(1, 8), t, Spacer(1, 4)]

def info_table(headers, rows, col_widths):
    data = [[Paragraph(h, ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9,
                        textColor=white, leading=12)) for h in headers]]
    for row in rows:
        data.append([Paragraph(str(c), ParagraphStyle('td', fontName='Helvetica',
                        fontSize=9, textColor=DARK_GRAY, leading=12)) for c in row])
    t = Table(data, colWidths=col_widths)
    style = [
        ('BACKGROUND', (0,0), (-1,0), TABLE_HEADER),
        ('ROWBACKGROUNDS', (0,1), (-1,-1), [white, TABLE_ALT]),
        ('GRID', (0,0), (-1,-1), 0.5, HexColor("#b0c4de")),
        ('TOPPADDING', (0,0), (-1,-1), 5),
        ('BOTTOMPADDING', (0,0), (-1,-1), 5),
        ('LEFTPADDING', (0,0), (-1,-1), 6),
        ('RIGHTPADDING', (0,0), (-1,-1), 6),
        ('VALIGN', (0,0), (-1,-1), 'TOP'),
    ]
    t.setStyle(TableStyle(style))
    return t

def build_pdf():
    doc = SimpleDocTemplate(
        OUTPUT_PATH,
        pagesize=A4,
        leftMargin=22*mm, rightMargin=22*mm,
        topMargin=20*mm, bottomMargin=22*mm,
        title="Spinal Cord: Complete Guide",
        author="Orris Medical Library",
        subject="Neuroanatomy - Spinal Cord"
    )

    story = []

    # ── COVER PAGE ──────────────────────────────────────────────────────────────
    cover_table = Table([[
        Paragraph("SPINAL CORD", S['title']),
    ]], colWidths=[165*mm])
    cover_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), DARK_BLUE),
        ('TOPPADDING', (0,0), (-1,-1), 30),
        ('BOTTOMPADDING', (0,0), (-1,-1), 10),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 10),
    ]))
    story.append(cover_table)

    sub_table = Table([[
        Paragraph("Ascending, Descending & Intersegmental Tracts", S['subtitle']),
    ]], colWidths=[165*mm])
    sub_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), MED_BLUE),
        ('TOPPADDING', (0,0), (-1,-1), 10),
        ('BOTTOMPADDING', (0,0), (-1,-1), 14),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 10),
    ]))
    story.append(sub_table)

    desc_table = Table([[
        Paragraph("Complete Neuroanatomy with Clinical Correlates", ParagraphStyle(
            'desc', fontName='Helvetica', fontSize=11, textColor=DARK_GRAY,
            alignment=TA_CENTER, leading=16)),
    ]], colWidths=[165*mm])
    desc_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), LIGHT_BLUE),
        ('TOPPADDING', (0,0), (-1,-1), 10),
        ('BOTTOMPADDING', (0,0), (-1,-1), 14),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 10),
    ]))
    story.append(desc_table)
    story.append(Spacer(1, 20))

    source_text = [
        "Sources: Gray's Anatomy for Students | Neuroanatomy through Clinical Cases |",
        "Localization in Clinical Neurology | Neuroscience: Exploring the Brain |",
        "Histology: A Text and Atlas | Bradley and Daroff's Neurology in Clinical Practice"
    ]
    for st in source_text:
        story.append(Paragraph(st, ParagraphStyle('src', fontName='Helvetica-Oblique',
            fontSize=9, textColor=MED_GRAY, alignment=TA_CENTER, leading=13)))
    story.append(Spacer(1, 10))
    story.append(Paragraph("July 2026", ParagraphStyle('date', fontName='Helvetica',
        fontSize=9, textColor=MED_GRAY, alignment=TA_CENTER)))

    story.append(PageBreak())

    # ── TABLE OF CONTENTS ───────────────────────────────────────────────────────
    story.extend(section_header("TABLE OF CONTENTS", S))
    toc_items = [
        ("1. Overview & General Anatomy", []),
        ("2. Spinal Meninges", []),
        ("3. External Features", []),
        ("4. Internal Features & Gray Matter", ["Rexed's Laminae", "White Matter Funiculi"]),
        ("5. Ascending Tracts", [
            "Anterolateral Pathways (Spinothalamic, Spinoreticular, Spinomesencephalic)",
            "Posterior Column - Medial Lemniscal Pathway",
            "Spinocerebellar Tracts",
        ]),
        ("6. Descending Tracts", [
            "Lateral Motor System (Corticospinal, Rubrospinal)",
            "Medial Motor System (Anterior Corticospinal, Vestibulospinal, Reticulospinal, Tectospinal)",
        ]),
        ("7. Intersegmental Tracts (Fasciculus Proprius)", []),
        ("8. Tract of Lissauer", []),
        ("9. Vascular Supply", []),
        ("10. Clinical Correlates", [
            "Brown-Sequard Syndrome",
            "Central Cord Syndrome & Syringomyelia",
            "Anterior Cord Syndrome",
            "Posterior Cord Syndrome",
            "Complete Cord Transection",
            "Cauda Equina Syndrome",
            "Tabes Dorsalis",
            "UMN vs LMN Lesions",
        ]),
        ("11. Summary Tables", []),
    ]
    for main, subs in toc_items:
        story.append(Paragraph(f"● {main}", S['toc_entry']))
        for sub in subs:
            story.append(Paragraph(f"◦ {sub}", S['toc_sub']))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 1: OVERVIEW
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("1. OVERVIEW & GENERAL ANATOMY", S))
    story.append(Paragraph("Introduction", S['h2']))
    story.append(Paragraph(
        "The spinal cord is a cylindrical structure of the central nervous system (CNS) that is continuous "
        "with the medulla oblongata near the foramen magnum at the base of the skull. It occupies the vertebral "
        "canal of the vertebral column, extending from the foramen magnum down to the LI-LII vertebral level in "
        "an adult (it is relatively longer in newborns, reaching LII-LIII). Numerous ascending and descending "
        "axonal tracts course through the spinal cord, connecting with the brain to convey sensory (afferent) and "
        "motor (efferent) information for facilitation of movement, reflexes, sensory input, and feedback mechanisms.",
        S['body']))

    story.append(Paragraph("Extent and Enlargements", S['h3']))
    rows = [
        ["Feature", "Detail"],
        ["Upper limit", "Foramen magnum (C1 level), continuous with medulla oblongata"],
        ["Lower limit (adult)", "LI-LII vertebral level - terminates as conus medullaris"],
        ["Lower limit (newborn)", "LII-LIII vertebral level"],
        ["Length", "Approximately 40-45 cm in adults"],
        ["Weight", "~30 grams"],
        ["Cervical enlargement", "C5-T1 - gives rise to brachial plexus (upper limb innervation)"],
        ["Lumbosacral enlargement", "L1-S2 - gives rise to lumbosacral plexus (lower limb innervation)"],
        ["Conus medullaris", "Pointed inferior end of spinal cord"],
        ["Filum terminale", "Fibrous extension from conus to coccyx; anchors cord"],
        ["Cauda equina", "Bundle of spinal nerve roots below the conus medullaris"],
    ]
    story.append(info_table(rows[0], rows[1:], [55*mm, 110*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph("Spinal Segments and Nerve Roots", S['h3']))
    story.append(Paragraph(
        "The spinal cord has 31 segments, each giving rise to a pair of spinal nerves through anterior (ventral) "
        "and posterior (dorsal) roots:", S['body']))
    seg_rows = [
        ["Region", "No. of Segments", "Vertebral Levels"],
        ["Cervical (C)", "8", "C1-C8"],
        ["Thoracic (T)", "12", "T1-T12"],
        ["Lumbar (L)", "5", "L1-L5"],
        ["Sacral (S)", "5", "S1-S5"],
        ["Coccygeal (Co)", "1", "Co1"],
    ]
    story.append(info_table(seg_rows[0], seg_rows[1:], [55*mm, 55*mm, 55*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph(
        "Note: Due to differential growth between the vertebral column and the spinal cord during development, "
        "the spinal cord segments do NOT correspond to the same-numbered vertebral levels below the cervical region. "
        "The nerve roots must travel increasingly longer distances caudally to reach their intervertebral foramina "
        "- this creates the cauda equina.", S['note']))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 2: MENINGES
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("2. SPINAL MENINGES", S))
    story.append(Paragraph(
        "Like the brain, the spinal cord is surrounded by three concentric meninges: the dura mater, "
        "arachnoid mater, and pia mater.", S['body']))

    meninges_rows = [
        ["Meninx", "Extent", "Key Features", "Clinical Importance"],
        ["Dura mater (outer)", "Foramen magnum to S2 vertebra",
         "Continuous with inner cranial dura; separated from bony vertebral canal by epidural/extradural space",
         "Epidural space used for epidural anaesthesia; spinal subdural hematoma rare"],
        ["Arachnoid mater (middle)", "Continuous; subarachnoid space to S2",
         "Less adherent to dura than intracranially; subdural space is a potential space",
         "Subarachnoid space: CSF flows here; lumbar puncture accesses this space safely below L2"],
        ["Pia mater (inner)", "Adherent to cord surface",
         "Highly vascular; forms denticulate ligaments and filum terminale interna",
         "Denticulate ligaments anchor cord in subarachnoid space"],
    ]
    story.append(info_table(meninges_rows[0], meninges_rows[1:], [30*mm, 38*mm, 55*mm, 42*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph("Denticulate Ligaments", S['h3']))
    story.append(Paragraph(
        "The pia mater, midway between the anterior and posterior roots, forms a flat continuous sheet called "
        "the denticulate ligament. At the posterior and anterior rootlets, sleeve-like projections extend out "
        "through the arachnoid mater to attach to the dura mater. These delicate attachments anchor and position "
        "the spinal cord within the central area of the subarachnoid space. There are 21 tooth-like projections "
        "on each side.", S['body']))

    story.extend(clinical_box("Lumbar Puncture (Spinal Tap)", [
        "Because the spinal cord ends at LI-LII but the subarachnoid space extends to S2, "
        "lumbar puncture is safely performed at the L3-L4 or L4-L5 interspace (below the conus medullaris) "
        "in adults. The needle passes through: skin → subcutaneous tissue → supraspinous ligament → "
        "interspinous ligament → ligamentum flavum → epidural space → dura mater → subdural space (brief) "
        "→ arachnoid → subarachnoid space (CSF obtained here).",
        "Indications: meningitis workup, subarachnoid hemorrhage diagnosis, intrathecal drug delivery.",
        "Contraindications: raised ICP with papilloedema (herniation risk), local infection, coagulopathy.",
    ], S))

    story.extend(clinical_box("Epidural Anaesthesia", [
        "Local anaesthetics injected into the epidural space (between dura mater and bony vertebral canal) "
        "block nerve roots as they cross this space. Used in obstetric analgesia, post-operative pain, and "
        "surgical anaesthesia for lower body procedures.",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 3 & 4: EXTERNAL AND INTERNAL FEATURES
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("3. EXTERNAL FEATURES", S))
    story.append(Paragraph(
        "The anterior and posterior surfaces of the spinal cord have several longitudinally running fissures and sulci:", S['body']))
    ext_rows = [
        ["Surface Feature", "Location", "Description"],
        ["Anterior median fissure", "Anterior midline", "Deep separation; contains anterior spinal artery"],
        ["Posterior median sulcus", "Posterior midline", "Shallower; continued inward by posterior median septum"],
        ["Posterolateral sulcus", "Bilateral, posterior", "Entry point of posterior (dorsal) nerve root rootlets"],
        ["Anterolateral sulcus", "Bilateral, anterior", "Less distinct; exit point of anterior (ventral) root rootlets"],
        ["Posterior intermediate sulcus", "Between post. median & posterolateral", "Present only in cervical cord; separates fasciculus gracilis from fasciculus cuneatus"],
    ]
    story.append(info_table(ext_rows[0], ext_rows[1:], [42*mm, 48*mm, 75*mm]))
    story.append(Spacer(1, 8))

    story.extend(section_header("4. INTERNAL FEATURES", S))
    story.append(Paragraph("Gray Matter", S['h2']))
    story.append(Paragraph(
        "A cross-section of the spinal cord reveals an inner H-shaped (or butterfly-shaped) gray matter "
        "consisting of neuronal cell bodies and an outer white matter composed of myelinated neuronal axons. "
        "The gray matter has distinct horns:", S['body']))

    horns_rows = [
        ["Horn", "Location", "Contents", "Function"],
        ["Anterior (Ventral) Horn", "Anterior lateral",
         "Alpha motor neurons (large), Gamma motor neurons (small), interneurons",
         "Motor output to skeletal muscles via ventral root"],
        ["Posterior (Dorsal) Horn", "Posterior lateral",
         "Sensory interneurons receiving afferent input",
         "Sensory processing and relay"],
        ["Lateral Horn (Intermediolateral column)", "T1-L2 and S2-S4",
         "Preganglionic autonomic neurons",
         "Sympathetic outflow (T1-L2); Parasympathetic outflow (S2-S4)"],
    ]
    story.append(info_table(horns_rows[0], horns_rows[1:], [38*mm, 30*mm, 52*mm, 45*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph("Motor Neuron Types in Anterior Horn", S['h3']))
    story.append(Paragraph(
        "Alpha (α) motor neurons: Large neurons that innervate extrafusal muscle fibers of skeletal muscles. "
        "Their axons constitute the final common pathway for motor control. Gamma (γ) motor neurons: Smaller "
        "neurons that innervate the intrafusal fibers (nuclear chain and nuclear bag fibers) of neuromuscular "
        "spindles - these are the receptors for the muscle stretch reflex. This allows central modulation of "
        "spindle sensitivity. Somatotopic organization: ventral horn neurons innervating flexor muscles lie "
        "dorsal to those innervating extensor muscles; neurons innervating distal muscles (hand) lie laterally "
        "to those innervating proximal/trunk muscles.", S['body']))

    story.append(Paragraph("Rexed's Laminae", S['h2']))
    story.append(Paragraph(
        "The Swedish anatomist Bror Rexed divided the spinal cord gray matter into 10 cytoarchitectural "
        "zones (laminae I-X), based on cell size, density, and arrangement. This system is critical for "
        "understanding synaptic targets of various tracts:", S['body']))

    rexed_rows = [
        ["Lamina", "Location", "Nucleus", "Function / Tract Connection"],
        ["I", "Tip of dorsal horn", "Nucleus posteromarginalis (Marginal zone)", "Receives pain/temp from Aδ & C fibers; origin of STT"],
        ["II", "Dorsal horn", "Substantia gelatinosa of Rolando", "Pain modulation; interneurons; gate control; opioid receptors"],
        ["III, IV", "Dorsal horn", "Nucleus proprius", "Touch, pressure, proprioception relay"],
        ["V", "Neck of dorsal horn", "Nucleus reticularis", "Wide dynamic range neurons; convergence of pain/touch; STT origin"],
        ["VI", "Base of dorsal horn", "Base of dorsal horn", "Present mainly in enlargements; proprioception from muscle spindles"],
        ["VII", "Intermediate zone", "Clarke's nucleus (C8-L2/L3); Intermediolateral column", "Clarke's nucleus: origin of posterior spinocerebellar tract; IML: preganglionic sympathetics"],
        ["VIII", "Ventral horn (medial)", "Commissural nucleus", "Interneurons; receives vestibulospinal and reticulospinal tracts"],
        ["IX", "Ventral horn", "Medial & lateral motor nuclei", "Alpha and gamma lower motor neurons"],
        ["X", "Around central canal", "Grisea centralis", "Surrounds central canal; visceral afferent input"],
    ]
    story.append(info_table(rexed_rows[0], rexed_rows[1:],
        [13*mm, 28*mm, 42*mm, 82*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph("White Matter - Funiculi (Columns)", S['h2']))
    story.append(Paragraph(
        "Each half of the spinal cord white matter is separated into three funiculi by the gray matter "
        "and intramedullary portions of the spinal nerve roots:", S['body']))
    funiculi_rows = [
        ["Funiculus", "Location", "Main Tracts", "Function"],
        ["Dorsal (Posterior)", "Between dorsomedian septum and dorsolateral sulcus",
         "Fasciculus gracilis; Fasciculus cuneatus",
         "Conscious proprioception, vibration, discriminative touch (ipsilateral)"],
        ["Lateral", "Between dorsolateral and ventrolateral sulci",
         "Lateral corticospinal (descending); Lateral spinothalamic, Spinocerebellar tracts (ascending); Rubrospinal",
         "Mixed motor and sensory functions"],
        ["Ventral (Anterior)", "Between ventrolateral sulcus and ventromedian fissure",
         "Anterior corticospinal; Anterior spinothalamic; Vestibulospinal; Reticulospinal; Tectospinal",
         "Motor (voluntary and postural); crude touch"],
    ]
    story.append(info_table(funiculi_rows[0], funiculi_rows[1:], [25*mm, 38*mm, 55*mm, 47*mm]))
    story.append(Spacer(1, 6))

    story.append(Paragraph(
        "Important Principle: White matter is thickest at cervical levels (most fibers present) and "
        "thinnest at sacral levels (most fibers have already terminated). Gray matter volume is greatest "
        "at the cervical and lumbosacral enlargements.", S['note']))

    story.extend(clinical_box("Conus Medullaris vs Cauda Equina Lesions", [
        "Conus medullaris lesion (S3-S5): Combined UMN + LMN picture. Bladder: spastic + flaccid (mixed). "
        "Saddle anesthesia. Erectile dysfunction. Perianal areflexia.",
        "Cauda equina lesion (below L2): Pure LMN lesion. Flaccid paralysis. Bladder: atonic/overflow incontinence. "
        "Absent reflexes. Severe radicular pain. Saddle anesthesia.",
        "Key difference: Cauda equina is peripheral nerve roots (PNS), so lesions cause LMN features; "
        "conus is spinal cord (CNS) causing mixed features.",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 5: ASCENDING TRACTS
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("5. ASCENDING TRACTS (SENSORY PATHWAYS)", S))
    story.append(Paragraph(
        "Sensory information entering the CNS from peripheral sensory receptors is conducted through a series "
        "of neurons that synapse with targets in the spinal cord, cerebral cortex, and other brain structures. "
        "The sensory modalities carried in these pathways include pain, temperature, tactile, and proprioceptive "
        "input. All conscious sensory pathways from the body follow a three-neuron chain: "
        "1st-order neuron (peripheral receptor to spinal cord/brainstem), "
        "2nd-order neuron (crosses midline, ascends to thalamus), "
        "3rd-order neuron (thalamus to cortex).", S['body']))

    story.append(Paragraph("Two Major Somatosensory Pathways:", S['h3']))
    story.append(Paragraph(
        "● Anterolateral system (ALS) - Pain, temperature, crude touch (crosses in spinal cord)",
        S['bullet']))
    story.append(Paragraph(
        "● Posterior column-medial lemniscal (PCML) pathway - Fine touch, vibration, conscious proprioception (crosses in medulla)",
        S['bullet']))

    # 5A: Anterolateral System
    story.append(Paragraph("5A. ANTEROLATERAL PATHWAYS", S['h2']))
    story.append(Paragraph(
        "The anterolateral system consists of three tracts that together convey pain, temperature, crude touch, "
        "and itch. They all begin with first-order neurons in the dorsal root ganglion:", S['body']))

    # Spinothalamic Tract
    story.append(Paragraph("i. Lateral Spinothalamic Tract (Neospinothalamic Tract)", S['h3']))
    story.append(Paragraph("Modalities: Sharp, well-localized pain and temperature", S['note']))

    stt_rows = [
        ["Neuron Order", "Cell Body Location", "Pathway", "Target"],
        ["1st Order Neuron", "Dorsal root ganglion (DRG)",
         "Enters spinal cord via posterior root → travels in Lissauer's tract (ascends/descends 1-2 segments) → synapses in posterior horn (laminae I and V)",
         "Posterior horn (ipsilateral)"],
        ["2nd Order Neuron", "Posterior horn (laminae I, V)",
         "Axons cross obliquely over 2-3 segments via anterior commissure → join anterolateral tract on contralateral side → ascend through spinal cord, brainstem",
         "VPL nucleus of thalamus"],
        ["3rd Order Neuron", "VPL nucleus, thalamus",
         "Projects via posterior limb of internal capsule",
         "Primary somatosensory cortex (S1), postcentral gyrus (areas 3,1,2)"],
    ]
    story.append(info_table(stt_rows[0], stt_rows[1:], [30*mm, 35*mm, 65*mm, 35*mm]))
    story.append(Spacer(1, 4))
    story.append(Paragraph(
        "Somatotopic Lamination in STT: Due to the laminar arrangement within the anterolateral tract, "
        "fibers from sacral levels are situated most laterally, and cervical fibers are situated most medially "
        "(or dorsomedially). This is clinically important in cordotomy procedures and in distinguishing "
        "intramedullary from extramedullary lesions.", S['note']))

    story.extend(clinical_box("Spinothalamic Tract - Key Clinical Points", [
        "Lesion ABOVE the level of decussation (e.g., lateral cord compression): Contralateral loss of pain "
        "and temperature sensation BELOW the level of the lesion.",
        "Lesion AT the level of decussation (anterior commissure, e.g., syringomyelia): BILATERAL loss of "
        "pain and temperature in a cape/vest-like distribution, sparing posterior column modalities "
        "(dissociated sensory loss).",
        "Anterolateral cordotomy: Surgical section of the STT for intractable pain relief; "
        "produces contralateral analgesia below the lesion level.",
        "STT carries fibers from OPPOSITE side; thus a right-sided cord lesion causes LEFT-sided pain/temp loss.",
        "Temperature: Temperature fibers are slightly dorsolateral to pain fibers within the STT.",
    ], S))

    story.append(Paragraph("ii. Anterior Spinothalamic Tract", S['h3']))
    story.append(Paragraph("Modalities: Crude (non-discriminative) touch, tickle, pressure", S['note']))
    story.append(Paragraph(
        "The anterior spinothalamic tract has a similar pathway to the lateral spinothalamic tract. "
        "First-order neuron cell bodies in the DRG enter the posterior horn, synapse in laminae VI and VII. "
        "Second-order axons cross via the anterior white commissure and ascend in the anterior funiculus. "
        "They project to the VPL nucleus of the thalamus and then to the somatosensory cortex. "
        "Note: Crude touch has BILATERAL representation to some degree because some uncrossed fibers travel "
        "in the ipsilateral posterior columns. Therefore, unilateral cord lesions may spare crude touch "
        "bilaterally.", S['body']))

    story.append(Paragraph("iii. Spinoreticular Tract", S['h3']))
    story.append(Paragraph("Modalities: Poorly localized, dull, aching, burning pain (affective/motivational component)", S['note']))
    story.append(Paragraph(
        "The spinoreticular tract is also called the paleospinothalamic pathway. First-order neurons "
        "are similar to the STT. Second-order axons ascend bilaterally in the anterolateral funiculus but "
        "instead of reaching the thalamus directly, they terminate on multiple synaptic stations in the "
        "brainstem reticular formation. From there, multisynaptic connections project to the intralaminar "
        "nuclei of the thalamus and then diffusely to the cortex. This pathway mediates the emotional, "
        "unpleasant, motivational, and arousal aspects of pain (suffering). It explains why lesions of the "
        "medial thalamus can relieve the suffering but not the sensation of pain.", S['body']))

    story.append(Paragraph("iv. Spinomesencephalic Tract (Spinotectal Tract)", S['h3']))
    story.append(Paragraph(
        "Second-order axons from the posterior horn ascend in the anterolateral funiculus and terminate in "
        "the midbrain: specifically the periaqueductal gray (PAG) matter and the superior colliculus. "
        "The PAG connection is important for endogenous pain modulation (descending inhibitory pathways). "
        "The superior colliculus connection mediates reflex orientation of head and eyes toward painful stimuli.", S['body']))

    story.extend(clinical_box("Gate Control Theory of Pain (Melzack & Wall, 1965)", [
        "Substantia gelatinosa (Lamina II) acts as a 'gate' modulating pain transmission. "
        "Large-diameter Aβ fibers (touch/vibration) can activate interneurons in SG that INHIBIT transmission "
        "from small C and Aδ fibers (pain). This explains why rubbing an injury reduces pain.",
        "Descending inhibition from PAG (via spinomesencephalic tract feedback), raphe nuclei (serotonin), "
        "and locus coeruleus (noradrenaline) also modulates pain at the dorsal horn level.",
        "Clinical application: TENS (Transcutaneous Electrical Nerve Stimulation) uses this principle.",
    ], S))

    story.append(PageBreak())

    # Posterior Column-Medial Lemniscal
    story.append(Paragraph("5B. POSTERIOR COLUMN - MEDIAL LEMNISCAL PATHWAY (DCML)", S['h2']))
    story.append(Paragraph(
        "Modalities: Fine (discriminative) touch, vibration sense, two-point discrimination, conscious proprioception (joint position sense), stereognosis (object recognition by touch), graphesthesia",
        S['note']))
    story.append(Paragraph(
        "This pathway has a key distinguishing feature: the first-order neurons ascend ipsilaterally all "
        "the way to the caudal medulla BEFORE decussating. Therefore, lesions in the spinal cord cause "
        "ipsilateral loss of these modalities.", S['body']))

    dcml_rows = [
        ["Neuron Order", "Cell Body", "Pathway", "Target"],
        ["1st Order", "DRG (large-diameter Aα, Aβ fibers)",
         "Enters cord via medial bundle of posterior root → ascends IPSILATERALLY in posterior funiculus. "
         "Lower limb fibers (T7 and below) → fasciculus gracilis (medial). "
         "Upper limb/neck fibers (above T6) → fasciculus cuneatus (lateral).",
         "Nucleus gracilis / Nucleus cuneatus (caudal medulla)"],
        ["2nd Order", "Nucleus gracilis (lower body) / Nucleus cuneatus (upper body) in caudal medulla",
         "Axons arc ventrally as internal arcuate fibers → decussate (sensory decussation) → "
         "form medial lemniscus on contralateral side → ascend through brainstem",
         "VPL nucleus of thalamus"],
        ["3rd Order", "VPL nucleus, thalamus",
         "Projects via posterior limb of internal capsule",
         "Primary somatosensory cortex (S1), areas 3,1,2"],
    ]
    story.append(info_table(dcml_rows[0], dcml_rows[1:], [22*mm, 35*mm, 73*mm, 35*mm]))
    story.append(Spacer(1, 4))

    story.append(Paragraph("Key Structures:", S['h3']))
    story.append(Paragraph(
        "Fasciculus Gracilis (Tract of Goll): Carries sensory information from the lower limb and trunk "
        "(T7 and below). Located medially in the posterior funiculus. Narrower in cross-section.",
        S['bullet']))
    story.append(Paragraph(
        "Fasciculus Cuneatus (Tract of Burdach): Carries information from the upper limb and neck "
        "(above T6). Located laterally in the posterior funiculus. Present only in thoracic and cervical cord.",
        S['bullet']))
    story.append(Paragraph(
        "Somatotopic arrangement in posterior columns: Sacral fibers are most medial, cervical fibers most lateral.",
        S['bullet']))

    story.extend(clinical_box("Posterior Column Lesions", [
        "Bilateral posterior column lesion (e.g., Subacute Combined Degeneration in Vit B12 deficiency, "
        "Friedreich's ataxia, Tabes dorsalis from syphilis): Loss of vibration sense, proprioception, "
        "fine touch bilaterally → sensory ataxia, positive Romberg's sign.",
        "Romberg's Sign: Patient can stand with feet together with eyes open (uses visual input) but falls "
        "when eyes closed (proprioceptive input lost). Sensory ataxia - not cerebellar ataxia.",
        "Lhermitte's Sign: Electric shock sensation radiating down spine and limbs on neck flexion - "
        "indicates posterior column pathology, classically seen in multiple sclerosis.",
        "Tabes dorsalis (neurosyphilis): Posterior column degeneration → lightning pains, Argyll Robertson "
        "pupils, sensory ataxia, absent deep tendon reflexes, Charcot joints.",
    ], S))

    # Spinocerebellar Tracts
    story.append(Paragraph("5C. SPINOCEREBELLAR TRACTS", S['h2']))
    story.append(Paragraph(
        "These tracts convey proprioceptive and exteroceptive information to the cerebellum for "
        "subconscious coordination of movement. They do NOT reach conscious awareness. "
        "There are four spinocerebellar tracts:", S['body']))

    sc_rows = [
        ["Tract", "Origin (1st neuron synapse)", "Course", "Enters Cerebellum Via", "Function"],
        ["Posterior Spinocerebellar Tract (PSCT)", "Clarke's nucleus (nucleus dorsalis), lamina VII, C8-L2/L3",
         "UNCROSSED - ascends ipsilaterally in lateral funiculus (posterior part)",
         "Inferior cerebellar peduncle (ICP)",
         "Subconscious proprioception from lower limb (muscle spindles, Golgi tendon organs)"],
        ["Anterior Spinocerebellar Tract (ASCT)", "Spinal border cells (laminae V-VII) lumbosacral",
         "CROSSES twice (once in cord, once in brainstem pons/midbrain) - net IPSILATERAL",
         "Superior cerebellar peduncle (SCP)",
         "Subconscious proprioception and exteroception from lower limb; information about spinal cord interneuronal activity"],
        ["Cuneocerebellar Tract", "Accessory (external/lateral) cuneate nucleus in medulla (C1-T6 input)",
         "UNCROSSED via ICP",
         "Inferior cerebellar peduncle",
         "Subconscious proprioception from upper limb and neck - functionally equivalent to PSCT"],
        ["Rostral Spinocerebellar Tract", "Laminae V, VI, VII in cervical cord",
         "Mostly UNCROSSED",
         "ICP and SCP",
         "Upper limb proprioception - functionally equivalent to ASCT"],
    ]
    story.append(info_table(sc_rows[0], sc_rows[1:], [30*mm, 35*mm, 37*mm, 28*mm, 35*mm]))
    story.append(Spacer(1, 4))

    story.extend(clinical_box("Spinocerebellar Tracts - Clinical", [
        "Friedreich's Ataxia: Degeneration of posterior spinocerebellar tracts AND posterior columns AND "
        "corticospinal tracts → progressive cerebellar + sensory ataxia, areflexia, cardiomyopathy. "
        "GAA trinucleotide repeat expansion in frataxin gene (chromosome 9).",
        "Multiple System Atrophy (MSA): Can affect spinocerebellar projections leading to cerebellar ataxia.",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 6: DESCENDING TRACTS
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("6. DESCENDING TRACTS (MOTOR PATHWAYS)", S))
    story.append(Paragraph(
        "Descending tracts through the spinal cord are involved in voluntary movements, postural control, "
        "and coordination of head, neck, and eye movements. These pathways originate from the cerebral "
        "cortex and brainstem and are influenced by feedback from the cerebellum and basal ganglia. "
        "They are divided into LATERAL and MEDIAL motor systems.", S['body']))

    story.append(Paragraph(
        "Upper Motor Neuron (UMN): Cell bodies in cerebral cortex or brainstem. Axons descend in the spinal cord. "
        "Lower Motor Neuron (LMN): Cell bodies in the anterior horn of spinal cord gray matter (Lamina IX). "
        "LMN axons exit via anterior root to form motor nerves.", S['note']))

    story.append(Paragraph("6A. LATERAL MOTOR SYSTEM", S['h2']))
    story.append(Paragraph(
        "Tracts of the lateral motor system are located in the lateral column of the spinal cord white "
        "matter and synapse on lower motor neurons in the LATERAL aspect of the anterior horn. They control "
        "voluntary movement of the extremities (distal muscles).", S['body']))

    # Lateral Corticospinal Tract
    story.append(Paragraph("i. Lateral Corticospinal Tract (Pyramidal Tract)", S['h3']))
    story.append(Paragraph(
        "This is clinically the MOST IMPORTANT descending tract. It is responsible for fine, voluntary, "
        "skilled movements - especially of the distal extremities (fingers, toes).", S['body']))

    lcst_rows = [
        ["Level", "Description"],
        ["Origin", "Primary motor cortex (M1, area 4), ~30%; premotor cortex (area 6), ~30%; "
         "somatosensory cortex (areas 3,1,2), ~40%"],
        ["Internal capsule", "Axons converge via corona radiata → posterior limb of internal capsule "
         "(somatotopic: face anteriorly, arm middle, leg posteriorly)"],
        ["Midbrain", "Descend in crus cerebri (middle 3/5)"],
        ["Pons", "Scattered into small bundles by transverse pontocerebellar fibers"],
        ["Medulla", "Reunited as pyramids (anterior surface of medulla) - hence 'pyramidal tract'"],
        ["Decussation", "~85-90% of fibers cross at pyramidal decussation (caudal medulla) to form LATERAL "
         "corticospinal tract (contralateral)"],
        ["Remaining fibers", "~10-15% stay ipsilateral → form ANTERIOR corticospinal tract"],
        ["Spinal cord descent", "Lateral funiculus, lateral column"],
        ["Synapse", "Lamina IX (anterior horn) - on alpha and gamma LMN cell bodies, directly or via interneurons"],
        ["Exit", "Anterior root → spinal nerve → motor nerve → neuromuscular junction"],
    ]
    story.append(info_table(lcst_rows[0], lcst_rows[1:], [35*mm, 130*mm]))
    story.append(Spacer(1, 4))

    story.append(Paragraph("Somatotopic Organization in Lateral Corticospinal Tract:", S['note']))
    story.append(Paragraph("In the lateral CST: Cervical fibers (arm) are most medial; Sacral fibers (leg) are most lateral. Clinically relevant when a tumor compresses cord from outside (sacral sparing) vs inside.", S['note']))

    story.extend(clinical_box("UMN vs LMN Syndrome", [
        "UMN lesion (lateral corticospinal tract): Spastic paralysis, hyperreflexia, upgoing plantar response "
        "(Babinski's sign), clonus, no significant muscle atrophy (disuse atrophy only), increased tone, "
        "initial flaccidity then spasticity (due to loss of descending inhibition on LMN).",
        "LMN lesion (anterior horn or peripheral nerve): Flaccid paralysis, hyporeflexia/areflexia, "
        "downgoing plantar, muscle wasting/atrophy, fasciculations, fibrillations on EMG.",
        "Babinski's sign (extensor plantar response): Dorsiflexion of big toe + fanning of other toes "
        "on stroking lateral sole. Present in UMN lesions; normal in infants <1 year.",
        "Clasp-knife rigidity: Velocity-dependent increase in tone (UMN); vs Lead-pipe or "
        "cogwheel rigidity (extrapyramidal).",
    ], S))

    # Rubrospinal Tract
    story.append(Paragraph("ii. Rubrospinal Tract", S['h3']))
    story.append(Paragraph(
        "Cell bodies of upper motor neurons begin in the red nucleus (nucleus ruber) of the midbrain tegmentum. "
        "After leaving the red nucleus, axons immediately cross the midline as the ventral tegmental decussation "
        "(Forel's decussation) in the midbrain. Axons then descend as the rubrospinal tract through the lateral "
        "column of the brainstem and lateral white matter of the spinal cord. These axons descend ONLY to "
        "cervical levels of the spinal cord and synapse with interneurons in the anterior horn gray matter. "
        "They facilitate flexor muscle activity and inhibit extensor muscle activity of the upper limb. "
        "In humans, this tract is relatively less significant than in other mammals, and its functional "
        "contribution may be partially subsumed by the corticospinal tract.", S['body']))

    story.append(Paragraph("6B. MEDIAL MOTOR SYSTEM", S['h2']))
    story.append(Paragraph(
        "Tracts of the medial motor system regulate axial and truncal muscles involved in maintaining "
        "posture, balance, and automatic gait-related movements. They also control orientating movements "
        "of the head and neck. Unlike the lateral motor system, these tracts project BILATERALLY on "
        "interneurons (not directly on LMNs) within the spinal cord. This makes each tract difficult "
        "to test individually in the clinical setting.", S['body']))

    # Anterior CST
    story.append(Paragraph("i. Anterior (Ventral) Corticospinal Tract", S['h3']))
    story.append(Paragraph(
        "Formed by the ~10-15% of corticospinal fibers that did NOT decussate at the pyramidal decussation "
        "in the caudal medulla. These axons remain IPSILATERAL and descend in the medial aspect of the "
        "anterior funiculus. They extend to the UPPER thoracic cord level, where they eventually cross in "
        "the anterior white commissure to synapse on contralateral (bilateral) anterior horn interneurons. "
        "These neurons control axial and proximal limb muscles.", S['body']))

    # Vestibulospinal Tracts
    story.append(Paragraph("ii. Vestibulospinal Tracts (Lateral and Medial)", S['h3']))
    vst_rows = [
        ["Tract", "Origin", "Course", "Function"],
        ["Lateral Vestibulospinal Tract", "Lateral vestibular nucleus (Deiters' nucleus), pons",
         "UNCROSSED; descends ipsilaterally in anterior funiculus throughout entire spinal cord",
         "Facilitates extensor muscle tone (antigravity muscles); inhibits flexors; maintains upright posture; balance"],
        ["Medial Vestibulospinal Tract", "Medial vestibular nucleus, pons",
         "Both CROSSED and UNCROSSED; descends only to cervical/upper thoracic cord in medial longitudinal fasciculus (MLF)",
         "Head and neck righting reflexes; head stabilization during movement"],
    ]
    story.append(info_table(vst_rows[0], vst_rows[1:], [35*mm, 38*mm, 47*mm, 45*mm]))
    story.append(Spacer(1, 4))

    story.extend(clinical_box("Decerebrate vs Decorticate Posturing", [
        "Decerebrate rigidity (midbrain-level lesion): Extension of all four limbs, jaw clenched, "
        "arms pronated. Due to unopposed lateral vestibulospinal tract activity (extensor facilitation). "
        "Indicates brainstem/midbrain compression - very poor prognosis.",
        "Decorticate rigidity (cortical/internal capsule lesion): Flexion of arms and extension of legs. "
        "Due to intact vestibulospinal and rubrospinal tracts with disrupted corticospinal tract. "
        "Less severe prognosis than decerebrate.",
    ], S))

    # Reticulospinal Tracts
    story.append(Paragraph("iii. Reticulospinal Tracts (Pontine and Medullary)", S['h3']))
    rst_rows = [
        ["Tract", "Origin", "Course", "Function"],
        ["Pontine (Medial) Reticulospinal Tract", "Pontine reticular formation (nucleus reticularis pontis caudalis & oralis)",
         "UNCROSSED; descends in anterior funiculus (medial reticulospinal tract)",
         "FACILITATES axial and proximal extensor tone; excites spinal cord LMNs"],
        ["Medullary (Lateral) Reticulospinal Tract", "Medullary reticular formation (nucleus reticularis gigantocellularis)",
         "Bilateral (mostly ipsilateral); descends in lateral funiculus",
         "INHIBITS spinal cord LMNs; regulates tone; pain modulation (endogenous opioid system)"],
    ]
    story.append(info_table(rst_rows[0], rst_rows[1:], [35*mm, 42*mm, 45*mm, 43*mm]))
    story.append(Spacer(1, 4))

    story.append(Paragraph(
        "Both reticulospinal tracts modulate spinal reflexes, muscle tone, and voluntary movement. "
        "They receive inputs from the motor cortex, cerebellum, and basal ganglia. The reticular formation "
        "also controls breathing, cardiovascular function, and consciousness.", S['body']))

    # Tectospinal Tract
    story.append(Paragraph("iv. Tectospinal Tract", S['h3']))
    story.append(Paragraph(
        "Origin: Superior colliculus (tectum) of the midbrain. After leaving the superior colliculus, "
        "axons cross the midline in the dorsal tegmental decussation (Meynert's decussation) in the "
        "midbrain. The tract then descends in the medial aspect of the anterior funiculus, only reaching "
        "the upper cervical cord (C4 or above). It synapses on interneurons in the anterior horn. "
        "Function: Mediates reflex turning of the head and eyes in response to visual stimuli "
        "(orientation reflex) and auditory/visual startle reflexes.", S['body']))

    story.extend(clinical_box("Spastic Gait and Tone Disorders", [
        "Spasticity (UMN syndrome): Results from disruption of cortical inhibitory projections via "
        "corticospinal tract AND disruption of medullary reticulospinal (inhibitory) tract, "
        "leaving pontine reticulospinal (excitatory) and vestibulospinal (facilitatory) tracts unopposed "
        "→ increased extensor tone. Velocity-dependent resistance (clasp-knife).",
        "Spinal Shock: Immediately after acute transection of spinal cord - flaccid paralysis, "
        "areflexia, urinary retention, ileus. Lasts days to weeks. Followed by gradual return of "
        "spasticity and hyperreflexia due to denervation supersensitivity of LMNs.",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 7: INTERSEGMENTAL TRACTS
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("7. INTERSEGMENTAL TRACTS", S))

    story.append(Paragraph("Fasciculus Proprius (Spinospinal Tract / Propriospinal Tract)", S['h2']))
    story.append(Paragraph(
        "The fasciculus proprius (also called the spinospinal tract, propriospinal fibers, or "
        "fasciculus proprius system) is a collection of short axonal fibers that form a thin zone of "
        "white matter surrounding the gray matter of the spinal cord like a sleeve. It is present in "
        "all three funiculi (anterior, posterior, lateral) but is most prominent in the anterior funiculus "
        "adjacent to the gray matter.", S['body']))

    story.append(Paragraph("Components and Structure:", S['h3']))
    story.append(Paragraph(
        "These fibers originate from interneurons within the gray matter and travel for various distances "
        "within the spinal cord - some spanning just one segment, others spanning several segments "
        "(hence 'intersegmental'). Fibers within the fasciculus proprius may be:",
        S['body']))
    story.append(Paragraph("&#9679; Short propriospinal fibers: span 1-2 segments (segmental coordination)", S['bullet']))
    story.append(Paragraph("&#9679; Long propriospinal fibers: span multiple segments (e.g., cervical to lumbar)", S['bullet']))
    story.append(Paragraph("&#9679; Both ascending and descending fibers are present", S['bullet']))
    story.append(Paragraph("&#9679; Most are ipsilateral, but some cross via anterior white commissure", S['bullet']))

    story.append(Paragraph("Functions:", S['h3']))
    fp_rows = [
        ["Function", "Detail"],
        ["Spinal reflex coordination", "Coordinates multi-segmental reflexes (e.g., scratching reflex, spinal locomotor patterns)"],
        ["Intersegmental coordination", "Coordinates activity between cervical and lumbar enlargements during locomotion (arm-leg coordination)"],
        ["Propriospinal rhythm generation", "Contributes to central pattern generators (CPGs) for rhythmic locomotion"],
        ["Autonomic coordination", "Coordinates sympathetic preganglionic cells across segments"],
        ["Alternative motor pathway", "After spinal cord injury, long propriospinal neurons may serve as relay for supraspinal commands, bypassing the lesion - basis for some recovery"],
    ]
    story.append(info_table(fp_rows[0], fp_rows[1:], [50*mm, 115*mm]))
    story.append(Spacer(1, 6))

    story.extend(clinical_box("Intersegmental Tracts - Clinical Relevance", [
        "After spinal cord injury, propriospinal interneurons (especially long propriospinal neurons - LPNs) "
        "can serve as neural detour circuits, relaying cortical commands from above the injury to spinal "
        "circuits below the injury. This is a major target for spinal cord injury rehabilitation research.",
        "Propriospinal myoclonus: A condition characterized by sudden jerks originating from propriospinal "
        "interneurons, often involving axial muscles; can be psychogenic or organic.",
        "Central Pattern Generators (CPGs): Located in the lumbar spinal cord (L1-L2 in humans); "
        "networks of propriospinal interneurons that generate rhythmic locomotor patterns independently of "
        "supraspinal input. Basis for epidural stimulation therapy in spinal cord injury rehabilitation.",
    ], S))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 8: TRACT OF LISSAUER
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("8. TRACT OF LISSAUER (POSTEROLATERAL TRACT)", S))
    story.append(Paragraph(
        "The posterolateral tract of Lissauer (zone of Lissauer, Lissauer's marginal zone) is a small "
        "bundle of thinly myelinated (Aδ) and unmyelinated (C) fibers located in the white matter between "
        "the tip of the posterior horn and the surface of the spinal cord. It separates the dorsal gray "
        "column from the surface of the spinal cord.", S['body']))

    story.append(Paragraph("Composition:", S['h3']))
    story.append(Paragraph(
        "&#9679; Primary afferent fibers (Aδ and C fibers) carrying pain, temperature, and itch",
        S['bullet']))
    story.append(Paragraph(
        "&#9679; Short ascending and descending branches of incoming dorsal root fibers",
        S['bullet']))
    story.append(Paragraph(
        "&#9679; Propriospinal axons of Lissauer's tract neurons",
        S['bullet']))
    story.append(Paragraph(
        "&#9679; Contains both pain-carrying and descending modulatory fibers",
        S['bullet']))

    story.append(Paragraph("Function:", S['h3']))
    story.append(Paragraph(
        "After entering the spinal cord via the lateral bundle of the posterior root, small-diameter "
        "pain/temperature fibers bifurcate into short ascending and descending branches within Lissauer's "
        "tract before synapsing on dorsal horn neurons in laminae I and II. This allows each incoming "
        "fiber to synapse on neurons over 1-2 spinal cord segments - an important mechanism for "
        "divergence of sensory input.", S['body']))

    story.extend(clinical_box("Lissauer's Tract - Clinical Note", [
        "The crossing of STT fibers through the anterior commissure takes place over 2-3 spinal cord segments. "
        "This is clinically important: after cordotomy (surgical section of the STT for pain relief), "
        "the surgeon must cut 2-3 segments ABOVE the painful dermatome to achieve adequate analgesia.",
        "The spread of syrinx (syringomyelia) destroys the anterior commissure crossing fibers → "
        "bilateral suspended sensory loss for pain/temperature at the level of the syrinx.",
    ], S))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 9: VASCULAR SUPPLY
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("9. VASCULAR SUPPLY OF THE SPINAL CORD", S))
    story.append(Paragraph(
        "The spinal cord has a relatively precarious vascular supply, making it vulnerable to ischemia.", S['body']))

    story.append(Paragraph("Arteries:", S['h3']))
    vasc_rows = [
        ["Artery", "Origin", "Territory", "Clinical Note"],
        ["Anterior Spinal Artery (ASA)", "Formed by convergence of 2 branches from vertebral arteries at foramen magnum; supplemented by radicular arteries",
         "Anterior 2/3 of spinal cord: corticospinal tracts, STT, anterior and lateral horns",
         "Most clinically important; supplies the motor and pain tracts"],
        ["Posterior Spinal Arteries (PSA) x2", "Vertebral arteries or PICA; continuous from medulla to conus",
         "Posterior 1/3 of spinal cord: posterior columns (fasciculus gracilis, cuneatus)",
         "Richer anastomotic network; less vulnerable to ischemia"],
        ["Artery of Adamkiewicz (Great anterior radicular artery)", "Usually from left T8-L2 intercostal or lumbar artery",
         "Critical reinforcement of ASA in thoracolumbar region",
         "Damage during aortic surgery → anterior spinal artery syndrome"],
        ["Radicular (segmental) arteries", "Aorta → intercostal/lumbar → radicular arteries",
         "Reinforce spinal arteries at various levels",
         "Most important: C5-C6 level, T1, and artery of Adamkiewicz"],
    ]
    story.append(info_table(vasc_rows[0], vasc_rows[1:], [38*mm, 42*mm, 42*mm, 43*mm]))
    story.append(Spacer(1, 6))

    story.extend(clinical_box("Anterior Spinal Artery Syndrome", [
        "Caused by occlusion of the anterior spinal artery (thrombosis, aortic dissection, "
        "aortic surgery, hypotension, vasculitis).",
        "Clinical features: Acute flaccid paralysis (later spastic), loss of pain and temperature sensation "
        "BELOW the level of the lesion (bilaterally), but PRESERVED vibration and proprioception "
        "(posterior columns spared) - classic dissociated sensory loss.",
        "Bladder and bowel dysfunction, autonomic disturbance.",
        "Pattern: PARALYSIS + PAIN/TEMP LOSS + PRESERVED PROPRIOCEPTION/VIBRATION.",
    ], S))

    story.extend(clinical_box("Posterior Spinal Artery Syndrome (Rare)", [
        "Occlusion of posterior spinal arteries: Loss of vibration, proprioception, and fine touch "
        "bilaterally BELOW the lesion. Motor function and pain/temperature PRESERVED.",
        "Far less common due to rich anastomotic network.",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 10: CLINICAL CORRELATES
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("10. CLINICAL CORRELATES & SPINAL CORD SYNDROMES", S))

    story.append(Paragraph(
        "Understanding the precise location of each tract allows precise anatomical localization of "
        "spinal cord lesions based on the pattern of neurological deficits.", S['body']))

    # Brown-Sequard
    story.append(Paragraph("10A. BROWN-SEQUARD SYNDROME (Spinal Cord Hemisection)", S['h2']))
    story.append(Paragraph(
        "Brown-Sequard syndrome results from hemisection (damage to one half) of the spinal cord. "
        "It is the classic example of dissociated sensory loss across the midline.", S['body']))

    bs_rows = [
        ["Finding", "Side", "Mechanism"],
        ["Ipsilateral spastic paralysis (UMN)", "SAME side as lesion, BELOW level",
         "Lateral corticospinal tract is ipsilateral (already decussated in medulla)"],
        ["Ipsilateral loss of fine touch, vibration, proprioception", "SAME side as lesion, BELOW level",
         "Posterior columns are ipsilateral (decussate in medulla)"],
        ["Contralateral loss of pain and temperature", "OPPOSITE side as lesion, BELOW level",
         "Spinothalamic tract crosses in anterior commissure 2-3 segments above entry"],
        ["Ipsilateral LMN signs AT the level of lesion", "SAME side, AT the level",
         "Anterior horn cell destruction at the level of injury"],
        ["Ipsilateral loss of all sensation AT the level", "SAME side, AT the level",
         "Dorsal root entry zone and posterior horn destruction"],
        ["Ipsilateral Horner's syndrome", "SAME side (if cervical lesion)",
         "Disruption of descending sympathetic fibers in ventral funiculus"],
    ]
    story.append(info_table(bs_rows[0], bs_rows[1:], [50*mm, 38*mm, 77*mm]))
    story.append(Spacer(1, 4))

    story.append(Paragraph(
        "Causes: Penetrating (stab wounds), herniated disc, tumor (primary/metastatic), multiple sclerosis, "
        "spinal cord ischemia, hematomyelia, spinal cord herniation, post-traumatic arachnoiditis.",
        S['note']))

    # Central Cord
    story.append(Paragraph("10B. CENTRAL CORD SYNDROME", S['h2']))
    story.append(Paragraph(
        "Central cord syndrome results from damage to the central portions of the spinal cord. "
        "The most common incomplete spinal cord injury pattern (50% of all incomplete injuries).", S['body']))

    story.append(Paragraph(
        "The classic presentation: arm weakness > leg weakness (because lateral CST fibers for the "
        "arm are medial and thus closer to the center; leg fibers are more lateral and sometimes spared). "
        "Bladder dysfunction (retention). Variable sensory loss below lesion.", S['body']))

    story.append(Paragraph(
        "Causes: Hyperextension injury in elderly with pre-existing spondylosis (most common), "
        "syringomyelia, hydromyelia, intramedullary tumors, hematomyelia.", S['note']))

    story.extend(clinical_box("Syringomyelia", [
        "A cystic cavity (syrinx) forms within the spinal cord, typically in the cervical region. "
        "The syrinx destroys the anterior commissure (crossing STT fibers) → bilateral suspended sensory "
        "loss for pain and temperature in a 'cape' or 'vest' distribution (upper back, arms, shoulders) - "
        "pain and temperature lost bilaterally at the level of the syrinx, but preserved above and below.",
        "As the syrinx expands: anterior horn → wasting of intrinsic hand muscles (LMN weakness); "
        "lateral horn (T1-L2) → Horner's syndrome (ptosis, miosis, anhidrosis); "
        "posterior columns → late vibration/proprioception loss; "
        "corticospinal tracts → spastic paraparesis.",
        "Associated with Chiari malformation (Type I), trauma, spinal tumors, arachnoiditis.",
        "Charcot joints (neuropathic arthropathy): Pain-insensate joints develop destructive arthropathy.",
    ], S))

    # Complete Cord
    story.append(Paragraph("10C. COMPLETE CORD TRANSECTION", S['h2']))
    story.append(Paragraph(
        "Complete transection (or destruction) of the spinal cord at any level produces:", S['body']))
    story.append(Paragraph("&#9679; Loss of ALL sensation below the level of the lesion (bilateral)", S['bullet']))
    story.append(Paragraph("&#9679; Complete flaccid paralysis initially (spinal shock) → later spastic paraplegia/tetraplegia", S['bullet']))
    story.append(Paragraph("&#9679; Loss of bladder, bowel, and sexual function", S['bullet']))
    story.append(Paragraph("&#9679; Loss of autonomic function below the lesion", S['bullet']))
    story.append(Paragraph("&#9679; Autonomic dysreflexia (if T6 or above): dangerous hypertensive episodes triggered by stimuli below the lesion", S['bullet']))

    story.extend(clinical_box("Autonomic Dysreflexia", [
        "A medical emergency in patients with spinal cord injuries at T6 or above. Triggered by noxious "
        "stimuli below the lesion (full bladder, impacted feces, pressure sores). "
        "Massive, uncontrolled sympathetic discharge below the lesion → severe hypertension. "
        "Bradycardia, sweating, flushing above the lesion (compensatory vagal response). "
        "Treatment: sit patient upright, identify and remove the trigger (most often urinary catheter blockage).",
    ], S))

    # Anterior and Posterior
    story.append(Paragraph("10D. ANTERIOR CORD SYNDROME", S['h2']))
    story.append(Paragraph(
        "Damage to the anterior 2/3 of the spinal cord. Typically caused by anterior spinal artery occlusion "
        "or anterior cord compression. Features: bilateral loss of motor function (corticospinal), bilateral "
        "loss of pain and temperature (STT), preserved posterior column functions (vibration, proprioception, "
        "fine touch). This is the pattern of anterior spinal artery syndrome.", S['body']))

    story.append(Paragraph("10E. POSTERIOR CORD SYNDROME", S['h2']))
    story.append(Paragraph(
        "Damage isolated to the posterior columns. Rare. Causes: posterior spinal artery occlusion, "
        "vitamin B12 deficiency (subacute combined degeneration - also involves lateral columns), "
        "syphilis (tabes dorsalis). Features: bilateral loss of vibration, proprioception, fine touch "
        "below the lesion. Motor function and pain/temperature preserved.", S['body']))

    story.extend(clinical_box("Tabes Dorsalis (Neurosyphilis)", [
        "Syphilitic degeneration of the posterior columns and posterior nerve roots. "
        "Features: Lightning pains (sudden, sharp shooting pains in legs), "
        "progressive sensory ataxia, Romberg's sign positive, wide-based gait, "
        "absent deep tendon reflexes, Charcot joints, bladder dysfunction (atonic bladder), "
        "positive Argyll Robertson pupils (accommodate but do not react to light - 'prostitute's pupil').",
        "Sensory loss: vibration, proprioception, fine touch (posterior column); pain/temp relatively preserved.",
    ], S))

    story.extend(clinical_box("Subacute Combined Degeneration of Spinal Cord (SACD)", [
        "Vitamin B12 (cobalamin) deficiency causes demyelination of posterior columns AND lateral "
        "columns (corticospinal tracts). Causes: pernicious anaemia, strict veganism, gastric surgery, "
        "nitrous oxide anesthesia (oxidizes B12).",
        "Features: Posterior column signs (vibration/proprioception loss, sensory ataxia, Romberg positive) "
        "+ UMN signs (spastic paraparesis, hyperreflexia, extensor plantars) - unique combination.",
        "Initially hyporeflexia (peripheral neuropathy can coexist), then hyperreflexia as cord disease worsens.",
        "SACD = BOTH posterior AND lateral columns (hence 'combined').",
        "Treatment: Intramuscular B12 replacement (hydroxocobalamin).",
    ], S))
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 11: SUMMARY TABLES
    # ══════════════════════════════════════════════════════════════════════════
    story.extend(section_header("11. SUMMARY TABLES", S))

    story.append(Paragraph("Complete Summary of All Spinal Cord Tracts", S['h2']))

    all_tracts = [
        ["Tract", "Type", "Funiculus", "Crosses?", "Modality/Function"],
        # Ascending
        ["Lateral Spinothalamic", "Ascending", "Lateral", "YES - ant. commissure (2-3 seg)", "Pain, temperature"],
        ["Anterior Spinothalamic", "Ascending", "Anterior", "YES - ant. commissure", "Crude touch, pressure"],
        ["Spinoreticular", "Ascending", "Anterolateral", "Bilateral", "Affective pain (suffering)"],
        ["Spinomesencephalic", "Ascending", "Anterolateral", "Partially", "Pain modulation, reflex orientation"],
        ["Fasciculus Gracilis", "Ascending", "Posterior (medial)", "NO (crosses in medulla)", "Proprioception/vibration/fine touch (lower body)"],
        ["Fasciculus Cuneatus", "Ascending", "Posterior (lateral)", "NO (crosses in medulla)", "Proprioception/vibration/fine touch (upper body)"],
        ["Post. Spinocerebellar", "Ascending", "Lateral (posterior)", "NO (ipsilateral)", "Subconscious proprioception (lower limb)"],
        ["Ant. Spinocerebellar", "Ascending", "Lateral (anterior)", "DOUBLE cross (net ipsilateral)", "Subconscious proprioception (lower limb, spinal cord activity)"],
        # Descending
        ["Lateral Corticospinal", "Descending", "Lateral", "YES - pyramidal decussation (medulla)", "Voluntary skilled movement (contralateral)"],
        ["Anterior Corticospinal", "Descending", "Anterior", "YES - at level in cord", "Axial/proximal muscle control (bilateral)"],
        ["Rubrospinal", "Descending", "Lateral", "YES - midbrain (ventral tegmental dec.)", "Flexor facilitation upper limb"],
        ["Lateral Vestibulospinal", "Descending", "Anterior", "NO (ipsilateral)", "Extensor tone, balance (antigravity)"],
        ["Medial Vestibulospinal", "Descending", "Anterior (MLF)", "Bilateral", "Head-neck righting reflexes"],
        ["Pontine Reticulospinal", "Descending", "Anterior", "NO (ipsilateral)", "Facilitates extensors"],
        ["Medullary Reticulospinal", "Descending", "Lateral", "Bilateral", "Inhibits LMNs, pain modulation"],
        ["Tectospinal", "Descending", "Anterior (medial)", "YES - midbrain (dorsal tegmental dec.)", "Reflex head-eye orientation (visual/auditory)"],
        # Intersegmental
        ["Fasciculus Proprius", "Both", "All (surrounds gray)", "Both ipsi and contra", "Intersegmental coordination, CPG, spinal reflexes"],
        ["Tract of Lissauer", "Both (local)", "Posterior (lateral tip)", "NO (stays within 1-2 segments)", "Entry zone for Aδ/C fibers, divergence of pain input"],
    ]
    story.append(info_table(all_tracts[0], all_tracts[1:], [38*mm, 20*mm, 22*mm, 40*mm, 45*mm]))
    story.append(Spacer(1, 10))

    story.append(Paragraph("Spinal Cord Syndrome Comparison", S['h2']))
    syn_rows = [
        ["Syndrome", "Motor", "Pain/Temp", "Vibration/Proprioception", "Cause"],
        ["Brown-Sequard", "Ipsilateral↓ UMN (below); ipsilateral LMN (at level)",
         "Contralateral↓ (below)", "Ipsilateral↓ (below)",
         "Hemisection: stab, MS, tumor"],
        ["Central Cord", "Arms > legs weakness (UMN)",
         "Bilateral loss (cape-like, at level of syrinx if syringomyelia)",
         "Variable", "Hyperextension, syringomyelia, intramedullary tumor"],
        ["Anterior Cord / ASA", "Bilateral↓ UMN (below)",
         "Bilateral↓ (below)", "PRESERVED",
         "Anterior spinal artery occlusion, aortic surgery"],
        ["Posterior Cord", "NORMAL",
         "NORMAL", "Bilateral↓",
         "Vit B12 deficiency, tabes dorsalis, PSA occlusion"],
        ["Complete Transection", "Bilateral↓ (all below)",
         "Bilateral↓ (all below)", "Bilateral↓",
         "Trauma, tumor, infarction"],
        ["Cauda Equina", "Flaccid↓ (LMN) saddle",
         "Saddle anesthesia", "Saddle loss",
         "Disc prolapse L4/L5, tumor, abscess"],
    ]
    story.append(info_table(syn_rows[0], syn_rows[1:], [32*mm, 33*mm, 33*mm, 33*mm, 34*mm]))
    story.append(Spacer(1, 10))

    story.append(Paragraph("UMN vs LMN Features - Quick Reference", S['h2']))
    ulmn_rows = [
        ["Feature", "UMN Lesion", "LMN Lesion"],
        ["Tone", "Increased (spasticity)", "Decreased (flaccidity)"],
        ["Reflexes (DTR)", "Increased (hyperreflexia)", "Decreased/absent (hypo/areflexia)"],
        ["Plantar response", "Upgoing (Babinski positive)", "Downgoing (normal/mute)"],
        ["Clonus", "Present", "Absent"],
        ["Muscle wasting", "Absent (disuse only)", "Present (neurogenic atrophy, fasciculations)"],
        ["Fasciculations", "Absent", "Present"],
        ["Fibrillations (EMG)", "Absent", "Present"],
        ["Distribution", "Widespread/pyramidal pattern", "Focal/segmental pattern"],
        ["Lesion location", "Brain, brainstem, spinal cord white matter", "Anterior horn, nerve root, peripheral nerve"],
    ]
    story.append(info_table(ulmn_rows[0], ulmn_rows[1:], [50*mm, 57*mm, 58*mm]))
    story.append(Spacer(1, 8))

    # Footer
    story.append(HRFlowable(width="100%", thickness=1, color=MED_BLUE))
    story.append(Spacer(1, 4))
    story.append(Paragraph(
        "Sources: Gray's Anatomy for Students (Elsevier) | Neuroanatomy through Clinical Cases 3rd Ed (Haines) | "
        "Localization in Clinical Neurology 8th Ed | Neuroscience: Exploring the Brain 5th Ed | "
        "Histology: A Text and Atlas (Pawlina) | Bradley and Daroff's Neurology in Clinical Practice | "
        "Compiled by Orris Medical Library, July 2026",
        ParagraphStyle('footer', fontName='Helvetica-Oblique', fontSize=8,
                       textColor=MED_GRAY, alignment=TA_CENTER, leading=11)))

    doc.build(story)
    print(f"PDF generated: {OUTPUT_PATH}")

if __name__ == "__main__":
    build_pdf()

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

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