cd /home/daytona/workspace/attachments/8bef5303-385b-40bb-bcfd-4215d2ba4441/ && …

cd /home/daytona/workspace/attachments/8bef5303-385b-40bb-bcfd-4215d2ba4441/ && …

"surgical anatomy" AND "head neck" AND "oral maxillofacial"

"facial nerve" AND "surgical anatomy" AND "head neck"

mkdir -p /home/daytona/workspace/surgical-anatomy-study-guide

~/surgical-anatomy-study-guide/generate_study_guide.py

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

# ── Color palette ──────────────────────────────────────────────────────────────
DARK_BLUE   = colors.HexColor("#1A3A5C")
MID_BLUE    = colors.HexColor("#2E6DA4")
LIGHT_BLUE  = colors.HexColor("#D6E8F7")
ACCENT_RED  = colors.HexColor("#C0392B")
ACCENT_GREEN= colors.HexColor("#1E7B4B")
GOLD        = colors.HexColor("#D4A017")
LIGHT_GRAY  = colors.HexColor("#F4F6F9")
MID_GRAY    = colors.HexColor("#BDC3C7")
WHITE       = colors.white
BLACK       = colors.HexColor("#1C1C1C")
WARN_BG     = colors.HexColor("#FFF3CD")
WARN_BORDER = colors.HexColor("#F0A500")
TIP_BG      = colors.HexColor("#E8F5E9")
TIP_BORDER  = colors.HexColor("#2ECC71")

OUTPUT = "/home/daytona/workspace/surgical-anatomy-study-guide/Surgical_Anatomy_HN_Study_Guide.pdf"

# ── Styles ─────────────────────────────────────────────────────────────────────
styles = getSampleStyleSheet()

def S(name, **kw):
    return ParagraphStyle(name, **kw)

COVER_TITLE = S("CoverTitle", fontSize=28, textColor=WHITE,
                fontName="Helvetica-Bold", alignment=TA_CENTER, leading=34)
COVER_SUB   = S("CoverSub",   fontSize=13, textColor=LIGHT_BLUE,
                fontName="Helvetica", alignment=TA_CENTER, leading=18)
COVER_DATE  = S("CoverDate",  fontSize=10, textColor=MID_GRAY,
                fontName="Helvetica", alignment=TA_CENTER)

MOD_TITLE   = S("ModTitle", fontSize=16, textColor=WHITE,
                fontName="Helvetica-Bold", alignment=TA_LEFT,
                leading=20, spaceBefore=2, spaceAfter=2)
SEC_TITLE   = S("SecTitle", fontSize=12, textColor=DARK_BLUE,
                fontName="Helvetica-Bold", leading=16,
                spaceBefore=10, spaceAfter=4)
BODY        = S("Body", fontSize=9.5, textColor=BLACK,
                fontName="Helvetica", leading=14,
                spaceBefore=2, spaceAfter=2, alignment=TA_JUSTIFY)
BULLET      = S("Bullet", fontSize=9.5, textColor=BLACK,
                fontName="Helvetica", leading=14,
                leftIndent=14, firstLineIndent=-10,
                spaceBefore=1, spaceAfter=1)
SUBBULLET   = S("SubBullet", fontSize=9, textColor=BLACK,
                fontName="Helvetica", leading=13,
                leftIndent=28, firstLineIndent=-10,
                spaceBefore=1, spaceAfter=1)
BOLD_INLINE = S("BoldInline", fontSize=9.5, textColor=BLACK,
                fontName="Helvetica-Bold", leading=14)
WARN_TXT    = S("WarnTxt", fontSize=9.5, textColor=colors.HexColor("#7D4E00"),
                fontName="Helvetica-Bold", leading=14,
                leftIndent=8, rightIndent=8,
                spaceBefore=4, spaceAfter=4)
TIP_TXT     = S("TipTxt", fontSize=9.5, textColor=colors.HexColor("#1B5E20"),
                fontName="Helvetica-Bold", leading=14,
                leftIndent=8, rightIndent=8,
                spaceBefore=4, spaceAfter=4)
REF_TXT     = S("RefTxt", fontSize=8.5, textColor=MID_BLUE,
                fontName="Helvetica-Oblique", leading=13,
                leftIndent=10)
TABLE_HDR   = S("TblHdr", fontSize=8.5, textColor=WHITE,
                fontName="Helvetica-Bold", alignment=TA_CENTER, leading=11)
TABLE_CELL  = S("TblCell", fontSize=8.5, textColor=BLACK,
                fontName="Helvetica", leading=12, alignment=TA_LEFT)
TABLE_CELL_C= S("TblCellC", fontSize=8.5, textColor=BLACK,
                fontName="Helvetica", leading=12, alignment=TA_CENTER)
FOOTER_TXT  = S("Footer", fontSize=7.5, textColor=MID_GRAY,
                fontName="Helvetica", alignment=TA_CENTER)

# ── Helpers ────────────────────────────────────────────────────────────────────
def module_header(num, title):
    """Dark blue banner for each module."""
    data = [[Paragraph(f"MODULE {num}  |  {title}", MOD_TITLE)]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE),
        ("TOPPADDING",    (0,0),(-1,-1), 7),
        ("BOTTOMPADDING", (0,0),(-1,-1), 7),
        ("LEFTPADDING",   (0,0),(-1,-1), 10),
        ("RIGHTPADDING",  (0,0),(-1,-1), 10),
        ("ROUNDEDCORNERS",(0,0),(-1,-1), [4,4,4,4]),
    ]))
    return t

def section_rule():
    return HRFlowable(width="100%", thickness=0.5, color=MID_BLUE,
                      spaceAfter=4, spaceBefore=6)

def warn_box(text):
    data = [[Paragraph(f"<b>! CLINICAL PEARL:</b>  {text}", WARN_TXT)]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0),(-1,-1), WARN_BG),
        ("LINEABOVE",     (0,0),(-1, 0), 2, WARN_BORDER),
        ("LINEBELOW",     (0,0),(-1,-1), 2, WARN_BORDER),
        ("LINEBEFORE",    (0,0),(0, -1), 4, WARN_BORDER),
        ("TOPPADDING",    (0,0),(-1,-1), 5),
        ("BOTTOMPADDING", (0,0),(-1,-1), 5),
        ("LEFTPADDING",   (0,0),(-1,-1), 8),
    ]))
    return t

def tip_box(text):
    data = [[Paragraph(f"<b>APPLIED TIP:</b>  {text}", TIP_TXT)]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0),(-1,-1), TIP_BG),
        ("LINEABOVE",     (0,0),(-1, 0), 2, TIP_BORDER),
        ("LINEBELOW",     (0,0),(-1,-1), 2, TIP_BORDER),
        ("LINEBEFORE",    (0,0),(0, -1), 4, TIP_BORDER),
        ("TOPPADDING",    (0,0),(-1,-1), 5),
        ("BOTTOMPADDING", (0,0),(-1,-1), 5),
        ("LEFTPADDING",   (0,0),(-1,-1), 8),
    ]))
    return t

def ref_line(text):
    return Paragraph(f"Ref: {text}", REF_TXT)

def b(t): return f"<b>{t}</b>"
def em(t): return f"<i>{t}</i>"
def red(t): return f'<font color="#C0392B"><b>{t}</b></font>'
def grn(t): return f'<font color="#1E7B4B"><b>{t}</b></font>'
def blu(t): return f'<font color="#2E6DA4"><b>{t}</b></font>'

def make_table(headers, rows, col_widths, alt=True):
    """Generic styled table."""
    hdr_row = [Paragraph(h, TABLE_HDR) for h in headers]
    data = [hdr_row]
    for i, row in enumerate(rows):
        data.append([Paragraph(str(c), TABLE_CELL) for c in row])
    t = Table(data, colWidths=col_widths)
    style = [
        ("BACKGROUND",    (0,0),  (-1,0),  DARK_BLUE),
        ("TEXTCOLOR",     (0,0),  (-1,0),  WHITE),
        ("GRID",          (0,0),  (-1,-1), 0.4, MID_GRAY),
        ("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"),
        ("ROWBACKGROUNDS",(0,1),  (-1,-1), [WHITE, LIGHT_GRAY]),
    ]
    t.setStyle(TableStyle(style))
    return t

def bp(txt):
    return Paragraph(f"&bull;  {txt}", BULLET)

def sbp(txt):
    return Paragraph(f"&#9702;  {txt}", SUBBULLET)

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

# ── Page layout ────────────────────────────────────────────────────────────────
PAGE_W, PAGE_H = A4
MARGIN = 2*cm

def on_page(canvas, doc):
    canvas.saveState()
    # Footer bar
    canvas.setFillColor(DARK_BLUE)
    canvas.rect(0, 0, PAGE_W, 1.1*cm, fill=1, stroke=0)
    canvas.setFillColor(WHITE)
    canvas.setFont("Helvetica", 7.5)
    canvas.drawCentredString(PAGE_W/2, 0.4*cm,
        f"Surgical Anatomy of Head & Neck  |  OMFS Study Guide  |  Page {doc.page}")
    # Top accent line
    canvas.setFillColor(GOLD)
    canvas.rect(0, PAGE_H-4, PAGE_W, 4, fill=1, stroke=0)
    canvas.restoreState()

def on_first_page(canvas, doc):
    # Full cover background
    canvas.setFillColor(DARK_BLUE)
    canvas.rect(0, 0, PAGE_W, PAGE_H, fill=1, stroke=0)
    canvas.setFillColor(GOLD)
    canvas.rect(0, PAGE_H-6, PAGE_W, 6, fill=1, stroke=0)
    canvas.rect(0, 0, PAGE_W, 6, fill=1, stroke=0)

# ── Build story ────────────────────────────────────────────────────────────────
story = []

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# COVER PAGE
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(Spacer(1, 5*cm))
story.append(Paragraph("SURGICAL ANATOMY", COVER_TITLE))
story.append(Paragraph("OF THE HEAD AND NECK", COVER_TITLE))
story.append(Spacer(1, 0.5*cm))
story.append(HRFlowable(width="60%", thickness=1.5, color=GOLD,
                         hAlign="CENTER", spaceAfter=12))
story.append(Paragraph("Applied Study Guide for OMFS Residents", COVER_SUB))
story.append(Spacer(1, 0.4*cm))
story.append(Paragraph("Department of Oral and Maxillofacial Surgery", COVER_SUB))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("Prepared by Dr. Hrushikesh Acharya (JR1) &bull; June 2026", COVER_DATE))
story.append(Spacer(1, 2*cm))

# Quick reference box on cover
cov_data = [[Paragraph(
    "<b>References:</b> Fonseca OMFS &bull; Peterson's Principles &bull; Ellis &amp; Zide Surgical Approaches &bull; "
    "Gray's Anatomy (Standring) &bull; Netter's H&amp;N &bull; Cummings Otolaryngology &bull; "
    "Scott-Brown's &bull; Kademani &amp; Tiwana Atlas &bull; Brennan Clinical H&amp;N Anatomy",
    COVER_DATE)]]
cov_t = Table(cov_data, colWidths=[13*cm])
cov_t.setStyle(TableStyle([
    ("BACKGROUND",(0,0),(-1,-1),colors.HexColor("#0F2A45")),
    ("BOX",(0,0),(-1,-1),1,GOLD),
    ("TOPPADDING",(0,0),(-1,-1),8),
    ("BOTTOMPADDING",(0,0),(-1,-1),8),
    ("LEFTPADDING",(0,0),(-1,-1),10),
]))
story.append(cov_t)
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 1: LAYERS TEMPLATE
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(1, "UNIVERSAL LAYERS TEMPLATE"))
story.append(sp(8))
story.append(Paragraph(b("The Seven-Layer Model (applies to every region — skin to bone)"), SEC_TITLE))
rows = [
    ["1. Skin",            "Thickness varies: thickest at scalp, thinnest at eyelid",    "Incision design; cosmetic units; graft harvest"],
    ["2. Subcutaneous fat","Facial fat compartments; superficial vessels; sensory nerves","Fat grafting; compartment shifts in ageing"],
    ["3. SMAS / Muscle",   "Galea → TPF → SMAS → platysma (one continuous sheet)",       "Face-lift plane; motor nerve lies DEEP to this"],
    ["4. Deep fascia",     "Parotid-masseteric (face); deep cervical fascia (neck)",      "Boundary of safe dissection zones"],
    ["5. Sub-fascial plane","Motor nerve branches, ducts, deep vessels, glands",          "HIGHEST-RISK surgical plane"],
    ["6. Periosteum",      "Vascularised, elevatable",                                   "Pericranial flap harvest; bone healing"],
    ["7. Bone",            "Cortical tables; buttresses",                                "Fixation; osteotomy lines; graft harvest"],
]
story.append(make_table(["Layer","Content","Surgical Significance"],
                        rows, [3*cm, 7.5*cm, 6.5*cm]))
story.append(sp(6))
story.append(warn_box(
    "GOLDEN RULE: Facial (motor) nerve branches lie DEEP to the SMAS. "
    "Dissecting superficial to the SMAS keeps you safe in most facial approaches."))
story.append(sp(6))
story.append(Paragraph(b("SMAS Continuity"), SEC_TITLE))
for txt in [
    f"{b('Superficial sheet:')} Galea aponeurotica (scalp) → Temporoparietal fascia/TPF (temple, {red('carries frontal branch CN VII')}) → SMAS (midface) → Platysma (neck)",
    f"{b('Deep fascia sheet:')} Deep temporal fascia → Parotid-masseteric fascia → Investing layer of deep cervical fascia",
    f"{b('Danger Space:')} Between alar fascia and prevertebral fascia. Infection tracks from skull base to mediastinum — descending necrotizing mediastinitis.",
]:
    story.append(bp(txt))
story.append(sp(4))
story.append(tip_box(
    "SMAS is a condensed fibromuscular layer contiguous with platysma, "
    "situated below subcutaneous fat and OVER the mimetic musculature and motor nerve branches. "
    "(Mitz & Peyronie 1974; confirmed in Cummings Otolaryngology)"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 2: SCALP
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(2, "THE SCALP"))
story.append(sp(8))
story.append(Paragraph(b("S-C-A-L-P Mnemonic"), SEC_TITLE))
rows = [
    ["S","Skin","Hair-bearing, thick",
     "Cosmetic incisions; hair restoration; graft donor site"],
    ["C","Connective tissue","Dense, fibrous, richly vascular",
     red("Scalp wounds bleed profusely — fibrous septa hold vessels open. Clamp before cutting")],
    ["A","Aponeurosis (Galea)","Tension-bearing layer",
     "Lacerations through galea gape widely — must close galea separately"],
    ["L","Loose areolar","DANGER LAYER — potential space",
     red("Infection/haematoma spreads here; emissary veins → dural sinuses → intracranial spread")],
    ["P","Pericranium (Periosteum)","Vascularised; elevatable",
     grn("Pericranial flap for frontal sinus obliteration, dural repair, scalp reconstruction")],
]
story.append(make_table(["Letter","Layer","Property","Applied Significance"],
                        rows, [1.5*cm, 3.5*cm, 5*cm, 7*cm]))
story.append(sp(8))
story.append(Paragraph(b("Calvarium Bone Graft Harvest"), SEC_TITLE))
for txt in [
    f"{b('Safe zone:')} Parietal bone, posterior to coronal suture, anterior to lambdoid suture; {b('outer table only')}",
    f"{b('Avoid:')} Sagittal suture (superior sagittal sinus directly beneath); thin temporal squama",
    f"{b('Why preferred:')} Membranous bone resists resorption; same operative field; minimal donor morbidity",
]:
    story.append(bp(txt))
story.append(sp(4))
story.append(warn_box(
    "A scalp flap raised in the LOOSE AREOLAR layer can devascularise the pericranium. "
    "Always identify and preserve the layer you are in."))
story.append(sp(4))
story.append(ref_line("Fonseca OMFS (Reconstruction Vol); Gray's Anatomy (Standring) — Scalp"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 3: FOREHEAD, FRONTAL SINUS, CORONAL APPROACH
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(3, "FOREHEAD, FRONTAL SINUS & CORONAL APPROACH"))
story.append(sp(8))
story.append(Paragraph(b("Forehead Layers"), SEC_TITLE))
for txt in [
    "Skin → Subcutaneous fat → Frontalis muscle (continuous with galea) → Loose areolar → Pericranium → Frontal bone",
    f"{b('Supraorbital notch/foramen:')} junction of medial 1/3 and lateral 2/3 of the orbital rim — supraorbital and supratrochlear nerves/vessels exit here",
    "Protect these during coronal dissection and all brow surgery — inadvertent traction causes forehead numbness",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Frontal Sinus — Fracture-Driven Management"), SEC_TITLE))
rows = [
    ["Anterior table alone",         "ORIF (plates/screws)",         "Cosmesis; contour"],
    ["Posterior table ± duct injury", "Obliteration or cranialization","CSF leak prevention"],
    ["Frontonasal duct injury",       "Obliteration (pericranial flap)","Prevent mucocele; meningitis"],
]
story.append(make_table(["Fracture Pattern","Management","Goal"],
                        rows, [5*cm, 6*cm, 6*cm]))
story.append(sp(6))
story.append(Paragraph(b("Temporal Region — 7 Layers"), SEC_TITLE))
layers = [
    ("1. Skin","—"),
    ("2. Subcutaneous","Superficial temporal artery/vein; auriculotemporal nerve"),
    (f"3. {red('TPF (Temporoparietal Fascia)')}",f"{red('Contains frontal branch of CN VII')} — most critical layer"),
    (f"4. {grn('Loose areolar')}",f"{grn('SAFE dissection plane')}"),
    ("5. Deep temporal fascia","Splits over arch — encloses superficial temporal fat pad"),
    ("6. Temporalis muscle","Coronoid process insertion — used as a flap"),
    ("7. Periosteum → Bone","—"),
]
rows2 = [[n, d] for n,d in layers]
story.append(make_table(["Layer","Notes"], rows2, [5.5*cm, 11.5*cm]))
story.append(sp(6))
story.append(warn_box(
    "PITANGUY'S LINE: Tragus → 1.5 cm above the lateral brow = course of the FRONTAL BRANCH of CN VII. "
    "The branch crosses the zygomatic arch within the TPF. Dissecting DEEP to the superficial layer of "
    "deep temporal fascia (sub-fascial plane) protects it."))
story.append(sp(6))
story.append(Paragraph(b("Coronal Approach — Safe Plane Protocol"), SEC_TITLE))
rows3 = [
    ["Frontal region","Subgaleal loose areolar plane","Below galea, above pericranium"],
    ["Temporal region","Below superficial layer of deep temporal fascia","Frontal branch stays in reflected flap"],
    ["At the arch","Incise deep temporal fascia obliquely; inter-fascial fat pad = visual guide","Strip periosteum off arch"],
]
story.append(make_table(["Zone","Safe Plane","Key Action"],
                        rows3, [4*cm, 7*cm, 6*cm]))
story.append(sp(4))
for txt in [
    f"{b('Access gained:')} Frontal sinus, NOE complex, orbital roofs, zygomatic arches, anterior skull base",
    f"{b('Pitfalls:')} Alopecia (tension on flap), frontal branch palsy, haematoma",
]:
    story.append(bp(txt))
story.append(sp(4))
story.append(ref_line("Ellis & Zide — Surgical Approaches to the Facial Skeleton; Pitanguy & Ramos, PRS 1966"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 4: ORBIT
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(4, "EYELID, PERIORBITA & ORBITAL SURGERY"))
story.append(sp(8))
story.append(Paragraph(b("Eyelid Layers (anterior → posterior)"), SEC_TITLE))
for txt in [
    f"Skin ({b('thinnest in the body')}) → Orbicularis oculi (pretarsal / preseptal / orbital) → {b('Orbital septum')} (KEY BARRIER — fat lies behind) → Preaponeurotic fat → Levator aponeurosis / capsulopalpebral fascia → Tarsus → Conjunctiva",
    f"{b('Medial canthal tendon (MCT):')} anchors the lid complex medially — critical in NOE fractures",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Orbital Walls & Contents"), SEC_TITLE))
for txt in [
    f"7 bones; {b('thinnest:')} lamina papyracea (medial wall) and orbital floor → why blowout fractures occur here",
    "Infraorbital nerve traverses the floor canal → at risk in midface trauma",
    f"Contents: globe, extraocular muscles, optic nerve, ophthalmic vessels",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Orbital Fractures"), SEC_TITLE))
rows = [
    ["Hydraulic","Globe compressed → pressure transmitted to thin floor/medial wall",
     "Fat ± inferior rectus herniation → diplopia, enophthalmos"],
    ["Buckling","Force along rim → bone buckles inward",
     "Can occur without significant rim deformity"],
    [f"{red('White-eyed blowout (paeds)')}","Trapdoor: muscle entrapped with minimal fat herniation",
     f"{red('SURGICAL EMERGENCY — vagal response, persistent diplopia')}"],
]
story.append(make_table(["Mechanism","Pathophysiology","Clinical Result"],
                        rows, [3.5*cm, 7*cm, 6.5*cm]))
story.append(sp(4))
story.append(warn_box(
    "FORCED DUCTION TEST distinguishes true muscle entrapment from nerve palsy. "
    "Entrapment = positive (restricted passive movement). Must perform under GA in the paediatric white-eyed blowout."))
story.append(sp(6))
story.append(Paragraph(b("Orbital Surgical Approaches"), SEC_TITLE))
rows2 = [
    [grn("Transconjunctival (preferred)"),
     "Inferior fornix → preseptal or retroseptal → periorbita → floor",
     "No cutaneous scar; lowest ectropion rate"],
    ["Subciliary",
     "2 mm below lash line → orbicularis → septum (do NOT open) → periosteum",
     "Ectropion risk 5-20%"],
    ["Lateral brow","Skin → orbicularis → periosteum → frontozygomatic suture","Limited access; FZ fixation"],
]
story.append(make_table(["Approach","Layers","Key Point"],
                        rows2, [4.5*cm, 7.5*cm, 5*cm]))
story.append(sp(6))
story.append(warn_box(
    f"{red('RETROBULBAR HAEMORRHAGE = BLINDNESS EMERGENCY.')}"
    " Signs: proptosis, RAPD, IOP >40 mmHg, pain. "
    "Immediate lateral canthotomy + inferior cantholysis within 90 minutes. "
    "Never dissect past the POSTERIOR THIRD of the floor (optic nerve)."))
story.append(sp(4))
story.append(ref_line("Ellis & Zide — Surgical Approaches to the Facial Skeleton"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 5: MIDFACE — SMAS, BUTTRESSES, LE FORT
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(5, "MIDFACE: SMAS, BUTTRESSES & LE FORT FRACTURES"))
story.append(sp(8))
story.append(Paragraph(b("Midface Soft-Tissue Layers"), SEC_TITLE))
story.append(bp("Skin → Subcutaneous fat (nasolabial, malar, jowl compartments) → SMAS (with mimetic muscles: zygomaticus major/minor, levator labii embedded within) → Parotid-masseteric fascia → Sub-SMAS plane (facial nerve branches, parotid duct, buccal fat pad) → Periosteum → Bone"))
story.append(sp(4))
rows = [
    ["Orbicularis oris","Sphincter of oral aperture","Cleft lip repair — must reconstruct muscular continuity"],
    ["Buccinator","Cheek compressor; pierced by Stensen's duct","Protect Stensen's duct in buccal approaches"],
    ["Mentalis","Chin elevator; inserts into chin skin","MUST RE-SUTURE in genioplasty — prevents 'witch's chin'"],
]
story.append(make_table(["Muscle","Function","Surgical Significance"],
                        rows,[4*cm, 6*cm, 7*cm]))
story.append(sp(6))
story.append(Paragraph(b("Midface Skeletal Buttresses"), SEC_TITLE))
for txt in [
    f"{b('Vertical buttresses:')} Nasomaxillary, Zygomaticomaxillary, Pterygomaxillary",
    f"{b('Horizontal buttresses:')} Frontal bar, Infraorbital rim, Maxillary alveolus",
    "Function: transmit and absorb masticatory and traumatic forces; dictate fracture lines",
    f"{b('Maxillary sinus:')} Roof = orbital floor; Floor = alveolus; Ostium in medial wall; lined by Schneiderian membrane",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Le Fort Fracture Classification"), SEC_TITLE))
rows2 = [
    ["I","Horizontal — floating palate",
     "Separates alveolus + palate from mid-face",
     "Malocclusion; maxillary mobility at alveolar level"],
    ["II","Pyramidal",
     "Nasofrontal suture + orbital floor + pterygoids",
     "CSF rhinorrhea; high haemorrhage risk"],
    ["III","Craniofacial disjunction",
     "Complete separation of facial skeleton from cranium",
     "Highest haemorrhage; airway emergency; dural tears"],
]
story.append(make_table(["Type","Name","Fracture Line","Complications"],
                        rows2,[1.5*cm,3.5*cm,5.5*cm,6.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("Le Fort I Osteotomy — Step-by-Step"), SEC_TITLE))
steps = [
    "Upper buccal sulcus mucosa incision (canine to canine bilaterally)",
    "Subperiosteal dissection — expose pyriform rim, infraorbital foramen, ZM buttress",
    "Osteotomy 1: Lateral nasal wall",
    "Osteotomy 2: Anterior maxillary wall — 5 mm above root apices (protect PSA vessels)",
    "Osteotomy 3: ZM buttress (bilateral)",
    f"Osteotomy 4: {red('Pterygomaxillary junction — MOST DANGEROUS')} (descending palatine + maxillary artery)",
    "Osteotomy 5: Nasal septum",
    "Downfracture with Rowe's disimpaction forceps",
    f"After downfracture: protect descending palatine artery, pterygoid plates, greater palatine pedicle",
]
for i, s in enumerate(steps, 1):
    story.append(Paragraph(f"<b>{i}.</b>  {s}", BULLET))
story.append(sp(4))
story.append(warn_box(
    "HAEMORRHAGE CONTROL in Le Fort I/II/III: precise osteotome placement → tight packing → "
    "maxillary artery ligation (in pterygopalatine fossa) → angiographic embolization if needed."))
story.append(sp(4))
story.append(ref_line("Fonseca OMFS; Miloro Peterson's Principles; Markowitz & Manson PRS 1991"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 6: NOSE & NOE
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(6, "NOSE, NOE COMPLEX & ZMC"))
story.append(sp(8))
story.append(Paragraph(b("Nasal Layers"), SEC_TITLE))
story.append(bp("Skin (thick at tip, thin at dorsum) → Subcutaneous/SMAS → Nasal muscles → Perichondrium/Periosteum → Cartilage framework (upper lateral, lower lateral, septal cartilages) → Nasal bones → Mucosa"))
for txt in [
    f"{b('Internal nasal valve:')} narrowest airway point (angle between upper lateral cartilage and septum) — key in functional rhinoplasty",
    f"{b('Blood supply:')} Angular artery (external carotid system) + Sphenopalatine artery branches (epistaxis source — posterior nasal bleeding)",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("NOE Fractures — Markowitz-Manson Classification"), SEC_TITLE))
rows = [
    ["Type I","Single central fragment","MCT attached and intact",
     "ORIF of single fragment; MCT intact"],
    ["Type II","Comminuted; MCT on a fragment","Comminuted but MCT attached",
     "Fixation of MCT-bearing fragment; no transnasal wiring usually"],
    ["Type III",f"{red('Comminuted; MCT detached')}","MCT avulsed from bone",
     f"{red('Transnasal canthopexy wiring required')}"],
]
story.append(make_table(["Type","Bone Pattern","MCT Status","Management"],
                        rows,[1.5*cm,4*cm,4*cm,7.5*cm]))
story.append(sp(4))
story.append(warn_box(
    "TELECANTHUS (increased intercanthal distance >35 mm) = sign of MCT avulsion. "
    "Bowstring test: pull eyelid laterally and palpate for MCT tightening over the nasal bridge. "
    "Also check for: nasolacrimal duct obstruction, CSF leak."))
story.append(sp(8))
story.append(Paragraph(b("ZMC — The Tetrapod"), SEC_TITLE))
for txt in [
    f"{b('4 articulations:')} Frontozygomatic, Zygomaticomaxillary, Zygomaticotemporal, Zygomaticosphenoid",
    f"{b('Nerve at risk:')} Infraorbital nerve (commonest sensory complication in midface surgery)",
    f"{b('Classification:')} Knight & North (6 types); Zingg (A/B/C)",
]:
    story.append(bp(txt))
story.append(sp(4))
rows2 = [
    ["Gillies temporal","Hairline → TPF → deep temporal fascia → temporalis → elevator under arch",
     "Minimal; only useful for isolated arch reduction"],
    ["Keen intraoral","Upper buccal sulcus behind ZM buttress",
     "PSA artery; pterygoid plexus haemorrhage"],
    ["Transconjunctival + upper buccal + lateral brow","Combination for full ZMC ORIF",
     "Covers all 4 sutures for fixation"],
]
story.append(make_table(["Approach","Layers / Access","Risk"],
                        rows2,[4*cm,7.5*cm,5.5*cm]))
story.append(sp(4))
story.append(ref_line("Ellis & Zide; Markowitz & Manson PRS 1991 (NOE)"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 7: PAROTID & PAROTIDECTOMY
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(7, "PAROTID GLAND & PAROTIDECTOMY"))
story.append(sp(8))
story.append(Paragraph(b("Parotid Layers — Superficial to Deep"), SEC_TITLE))
layers7 = [
    ("Skin","—"),
    ("Subcutaneous fat","—"),
    ("SMAS","—"),
    ("Parotid capsule (investing fascia)","Derived from investing layer of deep cervical fascia"),
    (f"{red('Facial nerve branches')}","Most superficial structure within gland parenchyma"),
    ("Retromandibular vein","Landmark within the gland — divides superficial/deep lobes"),
    ("External carotid artery","Deepest structure within the gland"),
]
rows7 = [[n, d] for n, d in layers7]
story.append(make_table(["Layer","Key Point"], rows7, [5.5*cm, 11.5*cm]))
story.append(sp(4))
for txt in [
    f"{b('Auriculotemporal nerve (V3):')} traverses gland — carries parasympathetic secretomotor fibres via otic ganglion (Frey syndrome pathway)",
    f"{b('Stensen\\'s duct:')} opens into the oral cavity opposite the upper 2nd molar; pierces buccinator",
    f"{b('Facial nerve divides gland')} into superficial and deep lobes — surgery DEMANDS trunk identification before lobar dissection",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Parotidectomy — Step-by-Step Approach"), SEC_TITLE))
steps7 = [
    f"Modified Blair incision (preauricular + posterior to the lobule + submandibular extension)",
    "Raise skin flap superficial to the parotid capsule",
    f"{b('Identify facial nerve trunk')} using 3 triangulating landmarks simultaneously:",
    f"{b('Landmark 1:')} 1 cm deep and inferior to the TRAGAL POINTER",
    f"{b('Landmark 2:')} 6-8 mm deep to the TYMPANOMASTOID SUTURE",
    f"{b('Landmark 3:')} Superior to POSTERIOR BELLY OF DIGASTRIC",
    "Alternatively: retrograde identification from a peripheral branch (buccal or marginal)",
    "Dissect superficial lobe off the nerve from trunk to periphery (teasing technique)",
    "Deep lobe: meticulous dissection around all nerve branches with bipolar haemostasis",
    f"{b('Frey syndrome prevention:')} SMAS flap or AlloDerm sheet interposed between skin and gland bed",
]
for i, s in enumerate(steps7, 1):
    story.append(Paragraph(f"<b>{i}.</b>  {s}", BULLET))
story.append(sp(4))
story.append(warn_box(
    "House-Brackmann Grade I-VI for facial nerve function assessment. "
    "Frey syndrome (auriculotemporal nerve misdirection) presents as gustatory sweating weeks to months post-op; "
    "treated with botulinum toxin injections."))
story.append(sp(4))
story.append(ref_line("Miloro Peterson's Principles; Cummings Otolaryngology; Kademani & Tiwana Atlas"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 8: TMJ, CONDYLE & ITF
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(8, "TMJ, CONDYLAR FRACTURES & INFRATEMPORAL FOSSA"))
story.append(sp(8))
story.append(Paragraph(b("TMJ Layers"), SEC_TITLE))
story.append(bp("Skin → Subcutaneous (superficial temporal vessels, auriculotemporal nerve) → TPF → Deep temporal fascia → Periosteum → Capsule → Superior joint space → Disc → Condyle"))
for txt in [
    f"{b('Disc:')} Biconcave fibrocartilage; bilaminar (retrodiscal) zone is vascular and innervated — source of pain in internal derangement",
    f"{b('Blood supply:')} Superficial temporal and maxillary arteries",
    f"{b('Innervation:')} Auriculotemporal nerve (V3)",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("TMJ Procedures"), SEC_TITLE))
rows8 = [
    ["Arthrocentesis","Holmlund-Hellsing line (tragus-lateral canthus)","Minimal; outpatient"],
    ["Arthroscopy","Superior joint space; avoid thin fossa roof","No open incision"],
    ["Open surgery / TJR","Preauricular or endaural incision",f"{red('Highest facial nerve risk')}"],
]
story.append(make_table(["Procedure","Access / Landmark","Key Risk"],
                        rows8,[4*cm,7*cm,6*cm]))
story.append(sp(6))
story.append(Paragraph(b("Condylar Fracture Management"), SEC_TITLE))
rows9 = [
    ["Retromandibular (transparotid)","Parotid; retromandibular vein = landmark",
     f"{red('CN VII risk (branches)')}","Subcondylar; displaced"],
    ["Endoscope-assisted transoral","No cutaneous scar; transoral endoscopic",
     "Technically demanding","Less nerve risk"],
]
story.append(make_table(["Approach","Anatomy","Risk","Indication"],
                        rows9,[4*cm,5.5*cm,3.5*cm,4*cm]))
story.append(sp(4))
story.append(bp(f"{b('Open ORIF indications:')} dislocation into middle cranial fossa; foreign body; lateral displacement; unobtainable occlusion"))
story.append(sp(6))
story.append(Paragraph(b("Infratemporal Fossa Contents"), SEC_TITLE))
rows10 = [
    ["Pterygoid muscles","Action: lateral pterygoid drives disc displacement and condyle fracture direction"],
    [f"{red('Pterygoid venous plexus')}", f"{red('Most dangerous venous bleed in the region — difficult to control')}"],
    ["Maxillary artery","Variable relation to lateral pterygoid — at risk in Le Fort I and ITF approaches"],
    ["V3 (mandibular nerve)","Motor + sensory; gives IAN and lingual nerve"],
    ["Chorda tympani","Taste from anterior 2/3 tongue; parasympathetics to submandibular gland"],
    [f"{red('Middle meningeal artery')}", f"{red('Enters foramen spinosum — laceration → epidural haematoma')}"],
]
story.append(make_table(["Structure","Applied Significance"], rows10,[5*cm,12*cm]))
story.append(sp(4))
story.append(ref_line("Miloro Peterson's Principles; Ellis & Zide; Kademani & Tiwana Atlas"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 9: MANDIBLE & LOWER FACE
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(9, "MANDIBLE, LOWER FACE & ORTHOGNATHIC SURGERY"))
story.append(sp(8))
story.append(Paragraph(b("Lower Face Layers"), SEC_TITLE))
story.append(bp(f"Skin → Subcutaneous → Platysma / Depressor muscles / Mentalis → Investing fascia → {red('Marginal mandibular nerve')} (superficial to facial vessels at the lower border) → Periosteum → Mandible"))
story.append(sp(4))
story.append(warn_box(
    "MARGINAL MANDIBULAR NERVE dips 1-2 cm BELOW the inferior border of the mandible in ~20% of patients. "
    "All submandibular incisions must be placed AT LEAST 2 cm below the inferior border. "
    "Hayes-Martin maneuver: ligate the facial vein and retract the nerve superiorly on the vascular stump."))
story.append(sp(6))
story.append(Paragraph(b("Mandibular Fracture Biomechanics"), SEC_TITLE))
rows_m = [
    ["Condyle","36%","Elevators (masseter, temporalis, medial pterygoid)",
     "Medial displacement (lateral pterygoid pull)"],
    ["Body","21%","Elevators vs. depressors",
     "Favorable (medial) vs. unfavorable (lateral) angulation"],
    ["Angle","20%","Pterygomasseteric sling",
     "Unfavorable — sling opens the fracture"],
    ["Symphysis","14%","Depressors (digastric, mylohyoid, geniohyoid)",
     "Anterior fragment pulled inferiorly; lip/chin numbness"],
]
story.append(make_table(["Site","Frequency","Muscle Force","Key Feature"],
                        rows_m,[3*cm,2.5*cm,5.5*cm,6*cm]))
story.append(sp(6))
story.append(Paragraph(b("IAN and Lingual Nerve — Applied Anatomy"), SEC_TITLE))
rows_n = [
    [f"{b('Inferior Alveolar Nerve')}",
     "Runs in mandibular canal; exits as mental nerve below 2nd premolar",
     "Third molars, BSSO, ORIF, implants — assess with CBCT pre-op",
     "0.5-5% (3rd molar); 13-40% transient in BSSO"],
    [f"{b('Lingual Nerve')}",
     "Submucosally on lingual plate; only 2-3 mm below alveolar crest at 3rd molar region",
     "Lingual flap elevation; elevator slip; lingual split technique",
     "0.5-2% (3rd molar)"],
]
story.append(make_table(["Nerve","Position","Risk Scenario","Incidence"],
                        rows_n,[3.5*cm,4.5*cm,5.5*cm,3.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("Mandibular Approaches"), SEC_TITLE))
rows_ap = [
    ["Intraoral vestibular","Mucosa → submucosa → mentalis/buccinator → periosteum → bone","Mental nerve"],
    ["Submandibular (Risdon)","Skin → subcutaneous → platysma → investing fascia → marginal mandibular n. (Hayes-Martin) → pterygomasseteric sling → periosteum → bone","Marginal mandibular nerve"],
]
story.append(make_table(["Approach","Layers","Primary Risk"],
                        rows_ap,[3.5*cm,9.5*cm,4*cm]))
story.append(sp(6))
story.append(Paragraph(b("Champy's Ideal Osteosynthesis Lines (1978)"), SEC_TITLE))
rows_ch = [
    ["Symphysis","2 plates — bicortical inferior; monocortical superior","High torsional stress"],
    ["Body","1 plate — superior border along external oblique","Tension zone superior"],
    ["Angle","1 plate — along external oblique ridge; monocortical superior, bicortical inferior","Sling opens fracture"],
]
story.append(make_table(["Region","Fixation","Rationale"],
                        rows_ch,[3*cm,8.5*cm,5.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("BSSO (Obwegeser-Dal Pont) — Step-by-Step"), SEC_TITLE))
bsso_steps = [
    "Intraoral incision anterior to the ramus",
    f"Medial cut: {b('above the lingula')} (horizontal medial osteotomy) — IAN canal just below",
    f"Sagittal cut: along the {b('external oblique ridge')}",
    "Inferior border cut connecting the two",
    f"{b('IAN must stay in the DISTAL segment')} — confirm with nerve hooks",
    "Split with osteotomes; avoid thin buccal plate (bad split risk)",
    f"{b('Risks:')} IAN injury 13-40% transient; bad/unfavorable split; inferior alveolar artery injury",
]
for i, s in enumerate(bsso_steps, 1):
    story.append(Paragraph(f"<b>{i}.</b>  {s}", BULLET))
story.append(sp(4))
story.append(tip_box(
    "GENIOPLASTY: osteotomy at least 5 mm below the mental foramen (to protect mental nerve). "
    "Always re-suture mentalis in 2 layers — failure causes 'witch's chin' deformity. "
    "Protect genioglossus/geniohyoid (tongue airway support)."))
story.append(sp(4))
story.append(ref_line("Champy et al. J Maxillofac Surg 1978; Miloro Peterson's Principles; Fonseca OMFS"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 10: FLOOR OF MOUTH & SUBMANDIBULAR
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(10, "FLOOR OF MOUTH, SUBLINGUAL & SUBMANDIBULAR"))
story.append(sp(8))
story.append(Paragraph(b("Mylohyoid — The Muscular Diaphragm"), SEC_TITLE))
for txt in [
    f"{b('Origin:')} Mylohyoid line (internal surface of mandible)",
    "Divides: sublingual space (above) from submandibular space (below)",
    f"{b('Applied:')} Root apex position relative to the mylohyoid line determines whether a dentoalveolar abscess presents in the sublingual or submandibular space",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Hyoglossus — The Master Landmark"), SEC_TITLE))
rows10a = [
    [grn("Superficial to hyoglossus"),
     "Lingual nerve, Wharton's duct, Hypoglossal nerve (CN XII), Sublingual gland"],
    [red("Deep to hyoglossus"),
     "Lingual artery, CN IX (glossopharyngeal nerve), Lingual vein"],
]
story.append(make_table(["Relation","Structures"], rows10a, [5*cm, 12*cm]))
story.append(sp(4))
story.append(warn_box(
    "LINGUAL ARTERY haemorrhage: ligate deep to hyoglossus or at the ECA origin. "
    "NEVER ligate bilaterally — vessels are only ~2 cm apart at the midline. "
    "Bilateral ligation causes tongue necrosis."))
story.append(sp(6))
story.append(Paragraph(b("Submandibular Triangle — 'Danger Quartet'"), SEC_TITLE))
story.append(bp("Layers: Skin → Subcutaneous → Platysma → Investing fascia → Marginal mandibular nerve (superficial) → Submandibular gland → 4 deep structures:"))
rows10b = [
    ["1. Facial artery","Enters triangle deep; exits superficial at anterior masseter border",
     "Double-ligate before dividing"],
    ["2. Lingual nerve","Superior to gland; wraps lateral→deep→medial around Wharton's duct",
     "Identify and preserve before duct ligation"],
    ["3. Hypoglossal nerve (CN XII)","Deepest; runs on surface of hyoglossus",
     "Preserve — innervates all intrinsic tongue muscles"],
    ["4. Facial vein","Runs superficially; used in Hayes-Martin maneuver",
     "Ligate to retract marginal mandibular nerve safely"],
]
story.append(make_table(["Structure","Anatomy","Applied Action"],
                        rows10b,[3.5*cm,7*cm,6.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("Submandibular Gland Excision — Step-by-Step"), SEC_TITLE))
smg_steps = [
    "Incision 2 cm below the inferior border of the mandible",
    "Divide skin → subcutaneous → platysma",
    f"{b('Hayes-Martin maneuver:')} ligate the facial vein → retract marginal mandibular nerve superiorly on the stump",
    "Double-ligate and divide the facial artery",
    "Mobilise the superficial lobe anteriorly and inferiorly",
    "Retract posterior border of mylohyoid — this opens the deep space",
    "Identify the lingual nerve (superior, wrapping Wharton's duct)",
    "Free lingual nerve from Wharton's duct by blunt dissection",
    "Identify and protect the hypoglossal nerve (deepest — on hyoglossus)",
    "Ligate and divide Wharton's duct flush at the sublingual caruncle",
    "Remove gland — layered closure + drain",
]
for i, s in enumerate(smg_steps, 1):
    story.append(Paragraph(f"<b>{i}.</b>  {s}", BULLET))
story.append(sp(4))
story.append(ref_line("Miloro Peterson's Principles; Cummings Otolaryngology; Brennan Clinical H&N Anatomy"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 11: NECK
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(11, "NECK ANATOMY, DISSECTION & DEEP SPACE INFECTIONS"))
story.append(sp(8))
story.append(Paragraph(b("Cervical Fascial Layers"), SEC_TITLE))
rows11 = [
    ["Investing layer","SCM, trapezius, parotid, submandibular gland",
     "Opened first in neck dissection; provides structural landmarks"],
    ["Pretracheal / visceral","Thyroid, trachea, esophagus",
     "Opens for tracheostomy; contains pretracheal space"],
    ["Prevertebral","Prevertebral muscles, spine",
     "NEVER breach — posterior to retropharyngeal space"],
    ["Carotid sheath","Carotid artery, IJV, vagus nerve",
     "Contributions from all 3 layers; protect in all neck surgery"],
]
story.append(make_table(["Layer","Encloses","Surgical Significance"],
                        rows11,[3.5*cm,5*cm,8.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("Lymph Node Levels — Drainage Map"), SEC_TITLE))
rows11b = [
    ["I (IA/IB)","Submental / Submandibular",
     "Floor of mouth, lips, anterior gingiva, submandibular gland"],
    ["II (IIA/IIB)","Upper jugular","Tongue, tonsil, oropharynx; IIA/IIB split by CN XI (spinal accessory)"],
    ["III","Middle jugular","Oral cavity, hypopharynx"],
    ["IV","Lower jugular",f"{red('Thoracic duct enters at LEFT level IV — chyle leak if damaged')}"],
    ["V","Posterior triangle",f"{red('CN XI (spinal accessory) at risk — trapezius paralysis')}"],
    ["VI","Central compartment","Thyroid, larynx, subglottis"],
]
story.append(make_table(["Level","Region","Drainage / Key Risk"],
                        rows11b,[2*cm,4*cm,11*cm]))
story.append(sp(6))
story.append(Paragraph(b("Neck Dissection Types"), SEC_TITLE))
rows11c = [
    ["Radical","Removes levels I-V + SCM + IJV + CN XI","Rarely used; significant morbidity"],
    ["Modified Radical","Levels I-V; preserves SCM and/or IJV and/or CN XI","Standard for N+ disease"],
    ["Selective","Level-specific; I-III for oral cavity SCC (supraomohyoid)","Elective N0 neck in oral cancer"],
    ["Extended","Includes additional structures (parotid, skin, carotid)","Extensive disease"],
]
story.append(make_table(["Type","Structures Removed/Preserved","Indication"],
                        rows11c,[3.5*cm,7.5*cm,6*cm]))
story.append(sp(6))
story.append(Paragraph(b("Deep Space Infection Spread Pathway"), SEC_TITLE))
for txt in [
    f"{b('Route:')} Odontogenic infection → Parapharyngeal space (adjacent to carotid sheath) → Retropharyngeal space → DANGER SPACE (alar-prevertebral) → Posterior mediastinum",
    f"{b('Result:')} Descending Necrotizing Mediastinitis — mortality 30-50% if not recognised and drained urgently",
    f"{b('Ludwig\\'s Angina:')} bilateral submandibular + submental + sublingual space infection — floor of mouth elevated, tongue pushed up → airway emergency",
]:
    story.append(bp(txt))
story.append(sp(4))
story.append(warn_box(
    "Any patient with floor of mouth swelling + trismus + dysphagia + stridor has a deep space infection "
    "until proven otherwise. Secure the airway FIRST (awake fibreoptic intubation or tracheostomy). "
    "CT with contrast defines the extent and the spaces involved."))
story.append(sp(4))
story.append(ref_line("Cummings Otolaryngology; Scott-Brown's; Fonseca OMFS"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 12: AIRWAY
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(12, "AIRWAY: TRACHEOSTOMY & CRICOTHYROIDOTOMY"))
story.append(sp(8))
story.append(Paragraph(b("Tracheostomy Layers (Outer to Airway)"), SEC_TITLE))
trach_layers = [
    ("Skin","—"),
    ("Subcutaneous fat","Anterior jugular veins (avoid; cauterise or retract)"),
    ("Platysma","—"),
    ("Investing fascia","—"),
    ("Strap muscles","Separate in the midline avascular raphe — do NOT cut"),
    ("Pretracheal fascia","—"),
    (f"{b('Thyroid isthmus')}","Lies over rings 2-4; retract superiorly or divide between ligatures"),
    (f"{b('Tracheal wall')}","Enter between rings 2-3 or 3-4; Bjork flap tacked to skin"),
]
rows12 = [[n,d] for n,d in trach_layers]
story.append(make_table(["Layer","Key Action/Risk"], rows12, [5.5*cm, 11.5*cm]))
story.append(sp(6))
story.append(Paragraph(b("Tracheostomy Complications"), SEC_TITLE))
rows12b = [
    [f"{red('Tracheoinnominate fistula')}","Brachiocephalic artery erosion by tube tip",
     f"{red('Hyperinflate cuff → emergency sternotomy')}"],
    ["RLN injury","Lateral dissection away from midline","Stay strictly midline below cricoid"],
    ["Thyroidea ima artery","Variant; present in 3-10%","Identify and ligate — can cause significant haemorrhage"],
    ["Subglottic stenosis","Cuff over-inflation; ischaemia","High-volume low-pressure cuffs; keep <20 cmH2O"],
]
story.append(make_table(["Complication","Mechanism","Prevention / Management"],
                        rows12b,[4.5*cm,5.5*cm,7*cm]))
story.append(sp(6))
story.append(Paragraph(b("Cricothyroidotomy"), SEC_TITLE))
for txt in [
    f"{b('Landmarks:')} Thyroid cartilage → palpate downward → cricothyroid membrane → cricoid cartilage",
    f"{b('Incision:')} Horizontal stab through the LOWER half of the cricothyroid membrane (avoid superior cricothyroid artery superiorly)",
    f"{red('CONTRAINDICATED in children <12')} — risk of subglottic stenosis and growth disturbance; use needle cricothyroidotomy instead",
    "Convert to formal tracheostomy within 24-72 hours",
]:
    story.append(bp(txt))
story.append(sp(4))
story.append(ref_line("Miloro Peterson's Principles; Fonseca OMFS; Cummings Otolaryngology"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 13: NERVE INJURY
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(13, "NERVE INJURY: CLASSIFICATION & MANAGEMENT"))
story.append(sp(8))
story.append(Paragraph(b("Classification Systems"), SEC_TITLE))
rows13 = [
    ["Neuropraxia","1st","Conduction block; axon intact","Full, spontaneous","Observation"],
    ["Axonotmesis","2nd","Axon lost; endoneurium intact","Good, spontaneous","Observation"],
    ["—","3rd","Axon + endoneurium lost","Incomplete","Medical ± surgical"],
    ["—","4th","Axon + endo + perineurium lost","Poor","Surgery usually needed"],
    ["Neurotmesis","5th","Complete transection","None","Surgery required"],
    ["—","6th (Mackinnon)","Mixed grade injury","Variable","Case-by-case"],
]
story.append(make_table(["Seddon","Sunderland","Pathology","Spontaneous Recovery","Management"],
                        rows13,[2.5*cm,3.5*cm,5.5*cm,3.5*cm,3*cm]))
story.append(sp(6))
story.append(Paragraph(b("Assessment Protocol"), SEC_TITLE))
for txt in [
    "History and examination: first and most important",
    f"{b('Neurosensory testing:')} light touch (cotton wool), two-point discrimination (2PD normal <6 mm), pinprick, thermal",
    f"{b('Imaging:')} MRI or high-resolution ultrasound for nerve continuity assessment",
    f"{b('Timeline:')} reassess at 1, 3, 6, and 12 months; most neuropraxia resolves by 3 months",
]:
    story.append(bp(txt))
story.append(sp(6))
story.append(Paragraph(b("Procedure-Specific Nerve Risks"), SEC_TITLE))
rows13b = [
    ["Third molar extraction","IAN","0.5-5%","CBCT pre-op; coronectomy if intimate"],
    ["Third molar extraction","Lingual nerve","0.5-2%","Avoid lingual flap; careful elevator placement"],
    ["BSSO","IAN (transient)","13-40%","Keep IAN in distal segment; avoid excessive retraction"],
    ["Le Fort I","Infraorbital nerve","Varies","Careful periosteal elevation; limit traction"],
    ["Parotidectomy","Facial nerve (all branches)","Varies by tumour","Trunk identification first; bipolar dissection"],
    ["Condylar ORIF","Marginal mandibular / frontal","Significant","Approach selection; nerve monitoring"],
    ["Submandibular excision","Marginal mandibular + hypoglossal","Significant","Hayes-Martin; identify and preserve CN XII"],
    ["Implant placement","IAN / mental nerve","Varies","2 mm clearance from IAN; assess anterior loop"],
]
story.append(make_table(["Procedure","Nerve at Risk","Incidence","Prevention"],
                        rows13b,[4*cm,3.5*cm,2.5*cm,7*cm]))
story.append(sp(4))
story.append(warn_box(
    "Trigeminal nerve injuries are LARGELY PREVENTABLE. They are often mixed "
    "(numbness + neuropathic pain), significantly impact quality of life, and carry medicolegal implications. "
    "Mandatory documented informed consent is required before every procedure where nerve risk exists. "
    "(Renton & Van der Cruyssen, Oral Surgery 2020)"))
story.append(sp(4))
story.append(ref_line("Seddon Brain 1943; Sunderland Brain 1951; Renton & Van der Cruyssen Oral Surg 2020"))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 14: COMPLICATIONS
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(14, "COMPLICATIONS — ANATOMICAL BASIS & MANAGEMENT"))
story.append(sp(8))
rows14 = [
    ["Third molar","IAN / lingual nerve injury",
     "Proximity — IAN in canal, lingual nerve 2-3 mm from crest",
     "Observe → medical (gabapentin/steroids) → microsurgery (<3 months)"],
    ["BSSO","Bad split / IAN injury",
     "Thin buccal plate; IAN intimacy with medial cortex",
     "Re-fixate; intraoperative nerve decompression; repair if transected"],
    ["Le Fort I","Haemorrhage",
     "Maxillary artery / descending palatine artery at pterygomaxillary junction",
     "Packing → maxillary artery ligation → embolisation"],
    ["Orbital repair","Blindness",
     "Retrobulbar haemorrhage; optic nerve posterior floor",
     "IMMEDIATE lateral canthotomy + inferior cantholysis"],
    ["Parotidectomy","Facial palsy / Frey syndrome",
     "CN VII in gland; auriculotemporal misdirection",
     "Nerve repair; botulinum toxin for Frey"],
    ["Neck dissection","Chyle leak",
     "Thoracic duct at left level IV",
     "Low-fat diet + pressure → surgical ligation"],
    ["Tracheostomy","Tracheoinnominate fistula",
     "Brachiocephalic artery erosion by cuff / tube tip",
     "Hyperinflate cuff → digital compression → emergency sternotomy"],
    ["BSSO / genioplasty","'Witch's chin'",
     "Mentalis not re-sutured; chin ptosis",
     "Prevention: 2-layer mentalis closure; late: revision surgery"],
    ["Orbital blowout repair","Inferior rectus entrapment post-plate",
     "Plate placed over inferior rectus",
     "Protect muscle; place mesh posterior to muscle bulk"],
]
story.append(make_table(["Procedure","Complication","Anatomical Basis","Management"],
                        rows14,[3.5*cm,3.5*cm,5*cm,5*cm]))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# MODULE 15: GRAND SUMMARY
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header(15, "GRAND SUMMARY — LANDMARKS & QUICK REFERENCE"))
story.append(sp(8))
story.append(Paragraph(b("Region-by-Region Summary Table"), SEC_TITLE))
rows15 = [
    ["Scalp","Loose areolar (danger layer)","Direct / coronal approach"],
    ["Temple","Frontal branch within TPF","Coronal — sub-fascial plane"],
    ["Orbit","Optic nerve; inferior rectus","Transconjunctival approach"],
    ["Midface","Descending palatine / maxillary artery","Upper buccal sulcus"],
    ["Parotid / TMJ","Facial nerve branches","Modified Blair / retromandibular"],
    ["Mandible","IAN, mental, marginal mandibular nerves","Vestibular / Risdon"],
    ["Floor of mouth","Lingual artery (deep to hyoglossus)","Transoral"],
    ["Submandibular","Danger quartet","Submandibular (Hayes-Martin)"],
    ["Neck","IJV, CN XI, carotid, thoracic duct","Selective neck dissection"],
    ["Airway","RLN, thyroid isthmus","Tracheostomy / cricothyroidotomy"],
]
story.append(make_table(["Region","Critical Structure","Primary Approach"],
                        rows15,[3.5*cm,7*cm,6.5*cm]))
story.append(sp(8))
story.append(Paragraph(b("Clinical Landmarks — Top to Bottom"), SEC_TITLE))
landmarks = [
    ("Supraorbital notch","Junction medial 1/3 : lateral 2/3 of orbital rim","Supraorbital / supratrochlear nerves + vessels"),
    ("Infraorbital foramen","1 cm below orbital rim on the pupillary line","Infraorbital nerve; injections; ORIF approach"),
    ("Tragal pointer","Tip of tragal cartilage","1 cm deep & inferior = CN VII trunk"),
    ("Pitanguy's line","Tragus → 1.5 cm above lateral brow","Frontal branch CN VII course"),
    ("Stensen's duct orifice","Opposite upper 2nd molar; anterior masseter border","Parotid duct; salivary calculi"),
    ("Mental foramen","Below 2nd premolar, 1 cm above lower border","Mental nerve; implant planning"),
    ("Hyoid bone","C3","Floor of mouth; tongue base attachment"),
    ("Thyroid cartilage","C4-C5","Carotid bifurcation level"),
    ("Cricothyroid membrane","Between thyroid and cricoid cartilages","Emergency airway"),
    ("Cricoid cartilage","C6","RLN enters larynx here; tracheostomy reference"),
    ("Tracheal rings 2-4","Below cricoid","Tracheostomy insertion site"),
]
rows_l = [[n,pos,sig] for n,pos,sig in landmarks]
story.append(make_table(["Landmark","Level / Location","Applied Significance"],
                        rows_l,[4.5*cm,4.5*cm,8*cm]))
story.append(sp(8))
story.append(Paragraph(b("Radiographic Landmarks"), SEC_TITLE))
rows_r = [
    ["OPG","Mandibular canal, mental foramen, lingula, pterygomaxillary fissure",
     "Review quadrant by quadrant; check symmetry; assess IAN proximity to roots"],
    ["CBCT","IAN canal 3D position, anterior mental loop, sinus septa, implant bone",
     "Mandatory before BSSO, complex extractions, implants"],
    ["CT","Frontal sinus tables, orbital walls, Le Fort lines, carotid encasement",
     "Carotid >270 encasement = inoperable; assess posterior table fractures"],
    ["Cephalometry","S, N, A, B, ANS, PNS, Go, Pog; SNA / SNB / ANB",
     "Orthognathic planning; ANB normal 2 degrees; class III <0 degrees"],
]
story.append(make_table(["Modality","Key Landmarks","Applied Use"],
                        rows_r,[2.5*cm,8*cm,6.5*cm]))
story.append(PageBreak())

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# REFERENCES
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
story.append(module_header("—", "REFERENCES"))
story.append(sp(8))
story.append(Paragraph(b("Standard Textbooks"), SEC_TITLE))
books = [
    "Fonseca RJ. Oral and Maxillofacial Surgery, 3rd Ed. Elsevier Saunders.",
    "Miloro M. Peterson's Principles of Oral and Maxillofacial Surgery, 3rd Ed. PMPH-USA.",
    "Ellis E, Zide MF. Surgical Approaches to the Facial Skeleton, 2nd Ed. Lippincott Williams & Wilkins.",
    "Kademani D, Tiwana PS. Atlas of Oral and Maxillofacial Surgery. Elsevier Saunders.",
    "Brennan PA. Clinical Head and Neck Anatomy for Surgeons. CRC Press.",
    "Standring S (Ed.). Gray's Anatomy: The Anatomical Basis of Clinical Practice, 41st Ed. Elsevier.",
    "Norton NS. Netter's Head and Neck Anatomy for Dentistry, 3rd Ed. Elsevier.",
    "Cummings CW et al. Cummings Otolaryngology: Head and Neck Surgery, 7th Ed. Elsevier.",
    "Scott-Brown's Otorhinolaryngology Head and Neck Surgery. CRC Press/Taylor & Francis.",
]
for b_ in books:
    story.append(bp(b_))
story.append(sp(8))
story.append(Paragraph(b("Key Articles"), SEC_TITLE))
articles = [
    "Seddon HJ. A classification of nerve injuries. Brain. 1943;66(4):237-288.",
    "Sunderland S. A classification of peripheral nerve injuries producing loss of function. Brain. 1951;74(4):491-516.",
    "Champy M, Lodde JP, Schmitt R, et al. Mandibular osteosynthesis by miniature screwed plates via a buccal approach. J Maxillofac Surg. 1978;6(1):14-21.",
    "Markowitz BL, Manson PN, Sargent L, et al. Management of the medial canthal tendon in nasoethmoid orbital fractures. Plast Reconstr Surg. 1991;87(5):843-853.",
    "Pitanguy I, Ramos AS. The frontal branch of the facial nerve: importance of its variations in face lifting. Plast Reconstr Surg. 1966;38(4):352-356.",
    "Renton T, Van der Cruyssen F. Diagnosis, pathophysiology, management and prevention of trigeminal nerve injuries. Oral Surg. 2020;13(4):397-423.",
    "Mitz V, Peyronie M. The superficial musculo-aponeurotic system (SMAS) in the parotid and cheek area. Plast Reconstr Surg. 1974;54(1):80-88.",
]
for a_ in articles:
    story.append(bp(a_))
story.append(sp(12))
story.append(HRFlowable(width="100%", thickness=1, color=GOLD, spaceAfter=8))
story.append(Paragraph(
    "Department of Oral and Maxillofacial Surgery  |  "
    "Prepared by Dr. Hrushikesh Acharya (JR1)  |  June 2026  |  "
    "For educational use only",
    FOOTER_TXT))

# ── Build document ──────────────────────────────────────────────────────────────
doc = BaseDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=MARGIN, rightMargin=MARGIN,
    topMargin=MARGIN+0.5*cm, bottomMargin=MARGIN+0.5*cm,
)

frame_cover = Frame(0, 0, PAGE_W, PAGE_H, leftPadding=MARGIN,
                    rightPadding=MARGIN, topPadding=MARGIN,
                    bottomPadding=MARGIN, id="cover")
frame_body  = Frame(MARGIN, 1.5*cm, PAGE_W-2*MARGIN, PAGE_H-3.5*cm,
                    id="body")

doc.addPageTemplates([
    PageTemplate(id="First", frames=[frame_cover], onPage=on_first_page),
    PageTemplate(id="Later", frames=[frame_body],  onPage=on_page),
])

from reportlab.platypus import NextPageTemplate
story.insert(0, NextPageTemplate("Later"))
story.insert(0, NextPageTemplate("First"))

# Shift cover elements to use cover frame properly
# Re-insert page template switch after cover PageBreak
# Find the PageBreak after cover and insert the template switch
for i, el in enumerate(story):
    if isinstance(el, PageBreak) and i > 3:
        story.insert(i+1, NextPageTemplate("Later"))
        break

doc.build(story)
print("PDF created:", OUTPUT)

cd /home/daytona/workspace/surgical-anatomy-study-guide && python3 generate_stud…

~/surgical-anatomy-study-guide/generate_study_guide.py

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/surgical-anatomy-study-guide/generate_study_guide.py'

cd /home/daytona/workspace/surgical-anatomy-study-guide && python3 generate_stud…

~/surgical-anatomy-study-guide/generate_study_guide.py

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/surgical-anatomy-study-guide/generate_study_guide.py'

cd /home/daytona/workspace/surgical-anatomy-study-guide && python3 generate_stud…

ls -lh /home/daytona/workspace/surgical-anatomy-study-guide/Surgical_Anatomy_HN_…