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Diseases & Pathology: 275 3D models

Disease models for every specialty — atherosclerosis to fractures, tumours, infections, blood smears, eye, ear and dental disease (real sizes µm–cm). Each one is a ready-made 3D model you can turn, recolour and place in a figure — open BioDioRama and type its name in the Library search.

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Cardiology & vascular · Neurology & neurosurgery · Pulmonology · Infectious disease · Gastroenterology & hepatology · Nephrology & urology · Endocrinology & diabetes · Haematology · Oncology · Dermatology & plastic surgery · Ophthalmology · ENT (otolaryngology) · Obstetrics & gynaecology · Dentistry & oral surgery · Orthopaedics & rheumatology · Cancer biology & carcinogenesis · Neurological disease — cells & molecules

Cardiology & vascular 25

Atherosclerotic plaque — A coronary-type artery cut open at its narrowest point: plaque growing in the intima with a lipid-rich necrotic core under a fibrous cap, foam cells and cholesterol crystals, narrowing the lumen. Choose the stage and the degree of stenosis. (artery ≈ 3–4 mm)
Fatty streak — The earliest lesion: lipid-laden foam cells collecting in the intima as yellow streaks, with no narrowing yet. (artery ≈ 3–4 mm)
Ruptured (vulnerable) plaque with thrombus — A thin-cap fibroatheroma that has fissured: blood meets the thrombogenic core and a platelet–fibrin thrombus grows into the lumen — the cause of most heart attacks. (artery ≈ 3–4 mm)
Calcified plaque — An advanced, calcified plaque with chalky deposits in its deep layers. (artery ≈ 3–4 mm)
Myocardial infarction — A block of left-ventricular wall below a coronary artery blocked by thrombus, with the infarct shown at a chosen age — from wavy fibres in the first hours through coagulative necrosis, macrophage clearance and granulation tissue to a white scar. (wall ≈ 1 cm)
Healed infarct (scar) — A healed transmural infarct: the dead muscle has been replaced by white fibrous scar. (wall ≈ 1 cm)
Abdominal aortic aneurysm — The infrarenal aorta cut open to show a fusiform (or saccular) aneurysm: thinned, calcified wall lined by laminated mural thrombus, between the renal arteries and the iliac bifurcation. (aorta ≈ 2 cm; AAA ≥ 3 cm)
Aortic dissection — An aorta split by an intimal flap into true and false lumens, with the entry tear letting blood into the false lumen and thrombus forming in its blind end. (aorta ≈ 3 cm)
Cerebral (berry) aneurysm — A saccular aneurysm at the bifurcation of the internal carotid into the anterior and middle cerebral arteries, with neck and dome; switch on rupture for subarachnoid blood. (dome ≈ 3–10 mm)
Deep vein thrombosis — A deep vein of the calf opened lengthwise: a thrombus that started in a valve pocket, laminated with lines of Zahn, propagating upward with a free-floating tail and a detaching embolus. (vein ≈ 5–10 mm)
Varicose vs normal vein — A healthy vein with competent valves beside a varicose vein — dilated, tortuous, with gaping valves that let blood flow backwards. (veins 3–10 mm)
Arteriolosclerosis (hyaline & hyperplastic) — Three arterioles cut across: normal, hyaline arteriolosclerosis (glassy thickened wall of hypertension and diabetes) and hyperplastic onion-skinning with fibrinoid necrosis (malignant hypertension). (arterioles ≈ 50 µm)
Aortic valve disease — The aortic root seen from above, cut away: three cusps in their sinuses of Valsalva with the coronary ostia. Conditions: normal, calcific stenosis, bicuspid valve, infective endocarditis with vegetations, rheumatic commissural fusion. (annulus ≈ 2.5 cm)
Calcific aortic stenosis — Thickened, calcified aortic cusps that can no longer open fully. (annulus ≈ 2.5 cm)
Infective endocarditis — Friable vegetations of platelets, fibrin and bacterial colonies on the closing edges of the cusps. (annulus ≈ 2.5 cm)
Cardiomyopathy (short-axis slice) — A short-axis slice through both ventricles: left ventricle with papillary muscles and the right ventricle around the septum. Conditions: normal, hypertrophic (asymmetric septal thickening, myocyte disarray), dilated, restrictive and arrhythmogenic right ventricular. (heart ≈ 10 cm)
Hypertrophic cardiomyopathy — Asymmetric septal hypertrophy with a slit-like cavity and myocyte disarray. (heart ≈ 10 cm)
Dilated cardiomyopathy — A dilated, thin-walled left ventricle with patchy fibrosis — systolic heart failure. (heart ≈ 10 cm)
Congenital heart defects — A frontal section of the heart with its great vessels, oxygenated blood red and deoxygenated blue. Defects: atrial or ventricular septal defect, patent ductus arteriosus, tetralogy of Fallot, coarctation of the aorta, transposition of the great arteries, hypoplastic left heart. (newborn heart ≈ 3 cm)
Atrial septal defect (ASD) — A hole in the atrial septum with left-to-right shunting. (newborn heart ≈ 3 cm)
Ventricular septal defect (VSD) — A hole in the ventricular septum with left-to-right shunting. (newborn heart ≈ 3 cm)
Tetralogy of Fallot — VSD, an aorta overriding the septum, pulmonary stenosis and right ventricular hypertrophy — mixed blood reaches the aorta. (newborn heart ≈ 3 cm)
Transposition of the great arteries — The aorta rises from the right ventricle and the pulmonary artery from the left; survival depends on mixing through the ductus. (newborn heart ≈ 3 cm)
Myocardial infarction (real heart) — A pale anterior-wall infarct with a hyperaemic border, from a thrombus in the left anterior descending artery. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Dilated cardiomyopathy (real heart) — An enlarged, globular heart with dilated ventricles. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

Neurology & neurosurgery 32

Stroke (coronal brain slice) — A coronal slice through both hemispheres: cortex, white matter, basal ganglia and ventricles, with a left middle cerebral artery stroke (dark irreversible core and salvageable penumbra behind the occluding clot) or a deep intracerebral haemorrhage with oedema and midline shift. (brain ≈ 14 cm)
Intracerebral haemorrhage — A deep (putaminal) haemorrhage with surrounding oedema compressing the ventricle and shifting the midline. (brain ≈ 14 cm)
Intracranial haemorrhage (epidural, subdural, SAH) — The layers between skull and brain with a bleed in the space of your choice: epidural (lens-shaped clot from a torn middle meningeal artery beneath a skull fracture), subdural (crescent from a torn bridging vein) or subarachnoid (blood in the CSF space). (layers ≈ 1 cm)
Subdural haematoma — A crescent-shaped clot between dura and arachnoid from a torn bridging vein, compressing the cortex. (layers ≈ 1 cm)
Subarachnoid haemorrhage — Blood filling the subarachnoid space and sulci, typically from a ruptured berry aneurysm. (layers ≈ 1 cm)
Alzheimer's disease (plaques & tangles) — Cortex in Alzheimer's disease: amyloid-β plaques with dense cores, fibrils and dystrophic neurites ringed by microglia; shrunken neurons filled with tau tangles; reactive astrocytes and amyloid in a vessel wall. Switch to "Normal" to compare. (plaques ≈ 50–200 µm)
Parkinson's disease (substantia nigra) — The substantia nigra: pigmented dopaminergic neurons full of neuromelanin; in Parkinson's disease most are lost, survivors carry Lewy bodies, and macrophages hold the released pigment. (neurons ≈ 50 µm)
Multiple sclerosis plaque — White matter with an active demyelinating plaque: myelinated axons outside, bare and transected axons inside, foamy macrophages full of myelin debris, reactive astrocytes and a cuff of T cells round the central venule. (plaque ≈ 1–20 mm)
Glioblastoma — A glioblastoma cut in half: a hypercellular mass of pleomorphic glioma cells with central necrosis rimmed by pseudopalisading cells, glomeruloid microvascular proliferation, haemorrhage and surrounding oedema. (tumour ≈ 3–6 cm)
Ischaemic stroke (real brain) — A dusky infarct across the territory of the middle cerebral artery. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Subarachnoid haemorrhage (real brain) — Blood spread over the base of the brain and into the Sylvian fissures. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Meningioma (real brain) — A firm, dural-based tumour pressing into the convexity, with a dural tail. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Brain — glass view of deep structures — The real brain with a see-through cortex showing the hippocampus, amygdala, basal ganglia, thalamus, corpus callosum, internal capsule, ventricles, brainstem and cerebellum. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Alzheimer's disease (real brain, Braak stages) — Tau pathology (purple) spreading in Braak order from the entorhinal cortex and hippocampus to the limbic and then the whole neocortex, with hippocampal atrophy, thinning cortex and widening ventricles. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Parkinson's disease (real brain, Braak stages) — Lewy pathology (brown) climbing the brainstem to the midbrain and cortex, a fading nigrostriatal dopamine pathway and a greying putamen as dopamine is lost. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Huntington's disease (real brain) — The caudate nucleus wasting (then the putamen) with ballooning frontal horns of the lateral ventricles (Vonsattel grades). Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Motor neurone disease / ALS (real brain) — Thinning of the motor cortex and degeneration of the corticospinal tracts from the cortex through the internal capsule into the brainstem. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Multiple sclerosis (real brain) — Ovoid demyelinating plaques round the ventricles (Dawson's fingers), in the corpus callosum, pons and cerebellum; later "black holes", atrophy and wider ventricles. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Hydrocephalus (real brain) — Enlarged lateral, third and fourth ventricles compressing the brain from within (communicating hydrocephalus). Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Obstructive hydrocephalus (aqueduct stenosis) — A blocked cerebral aqueduct: the lateral and third ventricles balloon while the fourth stays small. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Normal pressure hydrocephalus — Enlarged ventricles at normal pressure in an older adult — gait difficulty, incontinence and memory loss. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Temporal lobe epilepsy (hippocampal sclerosis) — The left hippocampus small and scarred with a wider temporal horn — the commonest cause of drug-resistant epilepsy. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Frontotemporal dementia (real brain) — Severe ("knife-edge") atrophy of the frontal and temporal lobes, sparing the back of the brain. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Haemorrhagic stroke (real brain) — A hypertensive bleed in the left putamen with surrounding oedema; larger stages shift the midline and spill into the ventricles. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Vascular dementia (small-vessel disease) — Lacunar infarcts in the deep grey matter and pons and confluent white-matter lesions round the ventricles. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Glioblastoma ("butterfly" across the corpus callosum) — A glioblastoma crossing the corpus callosum into both hemispheres: an irregular rim, a necrotic centre and surrounding oedema. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Medulloblastoma (child) — A tumour of the cerebellar vermis filling the fourth ventricle and blocking CSF flow, with hydrocephalus. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Traumatic brain injury (real brain) — Coup–contrecoup contusions at the frontal and temporal poles, petechial axonal injury in the corpus callosum and brainstem, and an acute subdural haematoma in severe injury. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Bacterial meningitis (real brain) — Yellow-green pus spreading over the brain's surface in the meninges, with congested vessels. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Herpes simplex encephalitis — Haemorrhagic necrosis of the medial temporal lobe and insula, first on one side then both. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Brain abscess — A pus-filled cavity with a capsule in the frontal lobe, ringed by oedema. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)
Arteriovenous malformation (AVM) — A tangle of abnormal vessels (nidus) on the left hemisphere with an enlarged feeding artery and draining vein. Drawn on the real brain from the BodyParts3D atlas. (adult brain, 16 cm)

Pulmonology 13

Airway disease (asthma, COPD, cystic fibrosis) — A bronchus cut open with the airway disease of your choice: asthma (mucus plug, thick basement membrane, hypertrophied smooth muscle, goblet cells, eosinophils), chronic bronchitis (enlarged mucous glands) or cystic fibrosis (dilated airway, thick infected mucus). Looks the same as: Asthma (airway remodelling). (bronchus ≈ 5 mm)
Chronic bronchitis (COPD) — Hypertrophied submucosal mucous glands (raised Reid index), goblet cells and chronic inflammation. (bronchus ≈ 5 mm)
Cystic fibrosis airway — A dilated airway clogged by thick mucus with Pseudomonas biofilm and neutrophils. (bronchus ≈ 5 mm)
Alveolar diseases — Alveoli cut open in one of seven states: normal, emphysema (destroyed walls, giant air spaces), lobar pneumonia (red or grey hepatisation), pulmonary oedema, ARDS (hyaline membranes) and pulmonary fibrosis (thick septa, fibroblastic foci). (alveoli ≈ 0.2 mm)
Emphysema — Destroyed alveolar walls merging into large air spaces with fewer capillaries. (alveoli ≈ 0.2 mm)
Lobar pneumonia — Alveoli filled with fibrinous exudate, neutrophils and red cells (red hepatisation). (alveoli ≈ 0.2 mm)
ARDS (diffuse alveolar damage) — Pink hyaline membranes lining the alveoli, thickened walls and type II cell hyperplasia. (alveoli ≈ 0.2 mm)
Pulmonary fibrosis — Thickened, scarred alveolar septa with fibroblastic foci. (alveoli ≈ 0.2 mm)
Pulmonary embolism & infarct — A saddle embolus lodged at a pulmonary artery bifurcation with a wedge-shaped haemorrhagic infarct at the pleural surface beyond the blocked branch. (lung segment ≈ 5 cm)
Emphysema (real lungs) — Pale, over-inflated lungs with apical bullae and black anthracotic pigment. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Lobar pneumonia (real lungs) — A dark red, solid (consolidated) lower lobe. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Pulmonary tuberculosis (real lungs) — Caseous granulomas and a cavity at the apex, with a Ghon focus. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Lung metastases (real lungs) — Many round metastatic nodules scattered through both lungs. Drawn on the real organ from the Human Reference Atlas. (adult organ)

Infectious disease 2

Tuberculous granuloma — A caseating granuloma cut in half: cheesy central necrosis, palisading epithelioid macrophages with acid-fast bacilli, horseshoe-nucleated Langhans giant cells, a lymphocyte cuff and a fibrous rim. (granuloma ≈ 1–3 mm)
Abscess — An abscess cut in half: a pool of pus — living and dead neutrophils, necrotic debris and bacterial colonies — walled off by granulation tissue and fibrosis. (abscess ≈ 1–5 cm)

Gastroenterology & hepatology 24

Liver disease (steatosis → cirrhosis) — Liver microscopy at a chosen stage: steatosis (fat droplets around the central vein), steatohepatitis (ballooned hepatocytes, Mallory–Denk bodies, neutrophils, chicken-wire fibrosis), bridging fibrosis, cirrhosis (regenerative nodules in fibrous septa) or chronic viral hepatitis. (lobule ≈ 1 mm)
Steatohepatitis (NASH/MASH) — Steatosis with ballooned hepatocytes, Mallory–Denk bodies, lobular inflammation and pericellular fibrosis. (lobule ≈ 1 mm)
Cirrhosis (microscopy) — Regenerative nodules of hepatocytes surrounded by fibrous septa with a ductular reaction. (lobule ≈ 1 mm)
Liver (gross) — cirrhosis, fatty liver, tumours — A whole liver with gallbladder, falciform ligament and IVC: normal, fatty (enlarged and yellow), cirrhotic (shrunken and nodular), with hepatocellular carcinoma, or riddled with metastases. (liver ≈ 15–20 cm)
Hepatocellular carcinoma (gross) — A bulging tumour with satellite nodules in a liver. (liver ≈ 15–20 cm)
Liver metastases — Multiple pale umbilicated metastatic deposits throughout the liver. (liver ≈ 15–20 cm)
Gallstones & cholecystitis — An opened gallbladder full of stones (faceted cholesterol, black pigment or mixed), with optional chronic wall thickening and a stone in the common bile duct. (gallbladder ≈ 8 cm)
Peptic ulcer — A chronic gastric ulcer punched through the mucosa and submucosa into the muscle: necrotic debris over granulation tissue and scar, an eroded artery with a visible vessel, neutrophils and H. pylori on the nearby surface. Switch on perforation for a full-thickness hole. (ulcer ≈ 1–3 cm)
Colon (opened) — IBD, polyps, cancer, diverticula — An opened segment of colon laid flat, mucosa up, with haustral folds and taenia: normal, ulcerative colitis (continuous, granular, pseudopolyps), Crohn's disease (skip lesions, cobblestoning, thick wall), polyps, annular carcinoma or diverticulosis. (segment ≈ 10 cm)
Ulcerative colitis — Continuous inflamed, granular, ulcerated mucosa from the rectum upward with pseudopolyps. (segment ≈ 10 cm)
Crohn's disease — Skip lesions with cobblestoned, thickened bowel and deep linear ulcers. (segment ≈ 10 cm)
Colorectal carcinoma (gross) — An annular "apple-core" carcinoma with rolled edges and central ulceration. (segment ≈ 10 cm)
Diverticulosis — Mucosal out-pouchings through the muscle wall, some with faecoliths. (segment ≈ 10 cm)
Adenoma–carcinoma sequence — Colorectal cancer development left to right on one wall: normal crypts, an aberrant crypt focus, a pedunculated tubular adenoma, a villous adenoma, invasive adenocarcinoma through the muscularis mucosae with desmoplasia, lymphatic tumour emboli and a lymph-node metastasis. (mucosa ≈ 1 mm; lesions mm–cm)
Coeliac disease (small bowel) — Small-bowel wall graded by the Marsh classification: from normal villi, through intraepithelial lymphocytosis and crypt hyperplasia, to partial, subtotal and total villous atrophy. (wall ≈ 2 mm)
Barrett's oesophagus — The gastro-oesophageal junction with Barrett's change: squamous epithelium replaced, past an irregular Z-line, by columnar epithelium with goblet cells (intestinal metaplasia); switch on dysplasia. (mucosa ≈ 1 mm)
Acute appendicitis — An appendix cut across: a faecolith blocking the lumen, ulcerated mucosa, neutrophils through every layer and fibrinopurulent exudate on the serosa. (appendix ≈ 7 mm)
Liver cirrhosis (real liver) — A shrunken, tawny liver covered in regenerative nodules. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Fatty liver (real liver) — An enlarged, pale yellow, greasy liver. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Liver metastases (real liver) — Many pale, umbilicated metastatic nodules on the surface of the liver. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Gallstones (real gallbladder) — Faceted cholesterol stones seen through the gallbladder wall. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Gastric ulcer (real stomach) — A punched-out crater on the lesser curvature with a fibrin base and an inflamed rim. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Diverticular disease (real colon) — Small outpouchings of the mucosa through the wall of the descending colon. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Appendicitis (real bowel) — A swollen, red, inflamed appendix. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

Nephrology & urology 14

Kidney (bisected) — stones, cysts, tumours — A kidney cut in half: capsule, cortex, medullary pyramids, calyces, pelvis, ureter and hilar vessels. Conditions: normal, stones (staghorn calculus), hydronephrosis, polycystic kidney disease, pyelonephritis, renal cell carcinoma with renal-vein thrombus, infarct. (kidney ≈ 11 cm)
Kidney stones (staghorn calculus) — A staghorn calculus filling the pelvis and calyces with smaller stones. (kidney ≈ 11 cm)
Hydronephrosis — Dilated pelvis and calyces with a thinned cortex above an obstructing ureteric stone. (kidney ≈ 11 cm)
Polycystic kidney disease — An enlarged kidney replaced by cysts, some haemorrhagic. (kidney ≈ 11 cm)
Renal cell carcinoma — A golden-yellow tumour at the upper pole with necrosis and tumour thrombus in the renal vein. (kidney ≈ 11 cm)
Glomerular diseases — A glomerulus showing the lesion of your choice: minimal change (effaced podocytes), FSGS (segmental scar), membranous (subepithelial deposits), diabetic nephropathy (Kimmelstiel–Wilson nodules, hyaline arterioles), crescentic, post-infectious (neutrophils, humps) or IgA nephropathy (mesangial deposits). (glomerulus ≈ 200 µm)
Focal segmental glomerulosclerosis — One segment of the tuft scarred and stuck to the capsule; podocyte foot processes effaced. (glomerulus ≈ 200 µm)
Crescentic glomerulonephritis — A crescent of proliferating parietal cells and macrophages filling Bowman's space. (glomerulus ≈ 200 µm)
Membranous nephropathy — Thickened capillary loops with subepithelial immune deposits. (glomerulus ≈ 200 µm)
Prostate (axial) — BPH & cancer — An axial slice of prostate around the urethra with the rectum behind: zones, benign hyperplasia nodules compressing the urethra into a slit (BPH), or an adenocarcinoma in the peripheral zone breaching the capsule. (prostate ≈ 4 cm)
Prostate cancer (gross) — Adenocarcinoma in the peripheral zone, palpable on rectal examination, breaching the capsule. (prostate ≈ 4 cm)
Polycystic kidney disease (real kidney) — An enlarged kidney studded with cysts of every size. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Kidney stones (real kidney) — A staghorn stone filling the pelvis and calyces and a stone in the ureter, seen through the kidney. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Bladder stones (real bladder) — Stones lying in the base of the bladder. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

Endocrinology & diabetes 10

Thyroid gland (gross) — goitre, nodules, cancer — The thyroid in front of the trachea and larynx: normal, diffuse goitre, multinodular goitre with colloid cysts, Graves' disease (enlarged, hypervascular), a solitary follicular adenoma, or carcinoma with nodal metastases. (lobes ≈ 5 cm)
Graves' disease (gross) — A diffusely enlarged, hypervascular thyroid. (lobes ≈ 5 cm)
Thyroid carcinoma (gross) — An infiltrative nodule with calcifications and cervical node metastases. (lobes ≈ 5 cm)
Thyroid disease (histology) — Thyroid microscopy by condition: normal, Graves' disease (tall cells, scalloped colloid), Hashimoto's thyroiditis (lymphoid follicles, Hürthle cells, atrophic follicles) or papillary carcinoma (fibrovascular papillae, clear grooved nuclei, psammoma bodies). Looks the same as: Hashimoto's thyroiditis. (follicles 50–500 µm)
Papillary thyroid carcinoma — Papillae with fibrovascular cores, clear grooved nuclei and psammoma bodies. (follicles 50–500 µm)
Diabetes — the islet — A pancreatic islet in diabetes: type 1 (insulitis — T cells destroying β cells, leaving mostly α cells) or type 2 (reduced β-cell mass with islet amyloid). (islet ≈ 50–300 µm)
Type 2 diabetes islet — Reduced β cells and amyloid deposits in the islet. (islet ≈ 50–300 µm)
Pituitary adenoma — The sella turcica from the front with the cavernous sinuses (carotid arteries, cranial nerves III, IV, V1, V2, VI): a micro- or macroadenoma, the latter growing upward to lift the optic chiasm. (adenoma 0.5–4 cm)
Multinodular goitre (real thyroid) — An enlarged thyroid with many colloid nodules. Drawn on the real organ from a model of the human thyroid gland on the trachea at true proportions. (adult organ)
Thyroid nodule (real thyroid) — A single nodule bulging from the right lobe. Drawn on the real organ from a model of the human thyroid gland on the trachea at true proportions. (adult organ)

Haematology 13

Blood smear (haematology) — A peripheral blood film viewed from above: red cells, white cells and platelets. Conditions: normal, iron-deficiency, megaloblastic, sickle cell, hereditary spherocytosis, thalassaemia (target cells), schistocytes (DIC/TTP), malaria, AML (blasts, Auer rods), CLL (smudge cells), CML and thrombocytopenia. (red cell ≈ 7.5 µm)
Iron-deficiency anaemia (smear) — Small, pale (microcytic, hypochromic) red cells. (red cell ≈ 7.5 µm)
Sickle cell disease (smear) — Sickled red cells among normal ones. (red cell ≈ 7.5 µm)
Malaria (smear) — Ring forms inside red cells and a banana-shaped P. falciparum gametocyte. (red cell ≈ 7.5 µm)
Acute myeloid leukaemia (smear) — Large myeloblasts with nucleoli and Auer rods; few platelets. (red cell ≈ 7.5 µm)
Chronic lymphocytic leukaemia (smear) — Many small mature lymphocytes and smudge cells. (red cell ≈ 7.5 µm)
Bone marrow disease — A bone-marrow biopsy: normal, acute leukaemia (packed with blasts), aplastic anaemia (empty, fatty), multiple myeloma (sheets of plasma cells, lytic lesion) or myelofibrosis (fibrosis, clustered megakaryocytes). (cells 8–100 µm)
Multiple myeloma (marrow) — Sheets of plasma cells with a lytic bone lesion. (cells 8–100 µm)
Aplastic anaemia (marrow) — A hypocellular, fatty marrow. (cells 8–100 µm)
Lymphoma (lymph node) — A lymph-node section: classical Hodgkin lymphoma (Reed–Sternberg "owl-eye" cells in a mixed background with collagen bands), diffuse large B-cell lymphoma (sheets of large cells, mitoses) or follicular lymphoma (back-to-back neoplastic follicles). (cells 8–50 µm)
Diffuse large B-cell lymphoma — Sheets of large atypical B cells with mitoses. (cells 8–50 µm)
Splenomegaly (real spleen) — A greatly enlarged spleen. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Splenic infarct (real spleen) — A pale wedge-shaped infarct reaching the capsule. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

Oncology 34

Tumour microenvironment — A solid tumour cut in half: proliferating cells outside, hypoxic cells and a necrotic core inside, tortuous leaky vessels, cancer-associated fibroblasts, dense collagen, M2 macrophages and T cells held at the margin — with nanoparticles leaking out of the vessels (EPR effect). (tumour ≈ 1–5 mm)
Carcinoma progression (dysplasia → invasion) — Squamous epithelium turning malignant from left to right: normal, mild, moderate and severe dysplasia, carcinoma in situ, then invasive carcinoma breaking through the basement membrane with keratin pearls, inflammation and tumour emboli in a lymphatic. (epithelium ≈ 0.3 mm)
Breast carcinoma (DCIS → invasive) — Breast tissue left to right: a normal two-layered duct, comedo-type DCIS (malignant cells filling a duct with central necrosis and calcification, myoepithelium intact), invasive ductal carcinoma nests in desmoplastic stroma with lymphocytes, and single-file invasive lobular carcinoma. (ducts ≈ 0.1–1 mm)
Lung cancer (non-small cell) — Non-small cell lung cancer in the right upper lobe. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Tobacco smoke (about 85%), radon, asbestos, air pollution. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Small cell lung cancer — A central, hilar small cell carcinoma with early bulky nodal spread. Stages: Limited, in situ; Limited — small central tumour; Limited — hilar mass; Limited — mediastinal nodes; Extensive — spread through the lung and beyond. Causes and risks: Almost always tobacco smoking. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Pleural mesothelioma — A pale rind of tumour growing over the pleura and encasing the lung. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Asbestos fibres, often 30–40 years earlier. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Breast cancer — An invasive ductal carcinoma in the upper outer quadrant of the left breast, with the axillary nodes. Stages: Ductal carcinoma in situ (DCIS); Stage I — under 2 cm; Stage II — 2–5 cm; Stage III — fixed axillary nodes; Stage IV — distant spread (bone, liver, lung, brain). Causes and risks: Oestrogen exposure, BRCA1/2 mutations, age, alcohol, obesity. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Colorectal cancer — An annular adenocarcinoma of the descending colon, encircling and narrowing the bowel. Stages: Stage 0 — in the mucosa; Stage I — into the muscle wall; Stage II — through the wall; Stage III — lymph nodes; Stage IV — liver and lung metastases. Causes and risks: APC → KRAS → TP53 mutations in an adenoma; red and processed meat, low fibre, obesity, inflammatory bowel disease, Lynch syndrome. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Rectal cancer — An adenocarcinoma of the rectum with the mesorectal nodes. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: As for colon cancer. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Gastric cancer — An ulcerated, fungating carcinoma of the stomach. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Helicobacter pylori, salted and smoked food, smoking, CDH1 mutations. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Diffuse gastric cancer (linitis plastica) — Signet-ring carcinoma spreading through the stomach wall and stiffening it ("leather bottle"). Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Often hereditary (CDH1). Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Oesophageal cancer — An adenocarcinoma at the junction of the oesophagus and stomach, arising in Barrett's oesophagus. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Acid reflux and Barrett's oesophagus (adenocarcinoma); smoking and alcohol (squamous). Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Hepatocellular carcinoma — A bulging liver cancer in the right lobe. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Hepatitis B and C, alcohol, fatty liver disease, aflatoxin — usually on a cirrhotic liver. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Cholangiocarcinoma (bile duct cancer) — A firm white tumour at the hilum of the liver where the bile ducts join. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Primary sclerosing cholangitis, liver flukes (Opisthorchis, Clonorchis), bile duct cysts. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Gallbladder cancer — A carcinoma of the gallbladder fundus. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Long-standing gallstones and chronic inflammation. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Pancreatic cancer — A pale ductal adenocarcinoma in the head of the pancreas. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Smoking, obesity, diabetes, chronic pancreatitis, KRAS mutations (over 90%). Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Renal cell carcinoma — A golden-yellow clear-cell carcinoma of the kidney. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Smoking, obesity, hypertension, VHL gene loss. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Bladder cancer (urothelial) — Papillary urothelial carcinoma growing on the bladder wall. Stages: Ta / CIS — superficial; Stage I — into the lamina propria; Stage II — into the muscle; Stage III — through the wall, pelvic nodes; Stage IV — distant spread. Causes and risks: Smoking, aromatic amines (dye industry), Schistosoma haematobium (squamous type). Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Prostate cancer — An adenocarcinoma in the peripheral zone of the prostate. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Age, family history, BRCA2, androgens. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Testicular cancer — A seminoma bulging from the testis. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Undescended testis, family history. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Ovarian cancer — A multiloculated cystic and solid serous carcinoma of the ovary. Stages: Borderline / in situ; Stage I — confined to the ovary; Stage II — pelvic spread; Stage III — peritoneum and nodes; Stage IV — distant spread. Causes and risks: BRCA1/2, Lynch syndrome, age, never having been pregnant. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Endometrial cancer — An endometrial carcinoma bulging from the body of the uterus. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Unopposed oestrogen, obesity, tamoxifen, Lynch syndrome. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Cervical cancer — A squamous cell carcinoma of the cervix. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Persistent high-risk HPV (types 16 and 18). Drawn on the real organ from the Human Reference Atlas. (adult organ)
Thyroid cancer (papillary) — A papillary carcinoma in the left lobe with the neck nodes. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Radiation exposure in childhood, BRAF and RET mutations. Drawn on the real organ from a model of the human thyroid gland on the trachea at true proportions. (adult organ)
Glioblastoma — A glioblastoma breaking through the cortex of the left hemisphere, with haemorrhage and necrosis. Brain tumours rarely reach lymph nodes; their stages are grades. Stages: Low-grade glioma (grade 1); Grade 2; Grade 3; Grade 4 (glioblastoma); Grade 4, multifocal. Causes and risks: Mostly unknown; ionising radiation, rare inherited syndromes. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Brain metastases — Round metastatic deposits at the grey–white junction, from lung, breast, kidney or melanoma. Stages: Micrometastasis; Single metastasis; Two or three; Several; Many (miliary). Causes and risks: Spread of a cancer elsewhere. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Oral cancer (tongue) — An ulcerated squamous cell carcinoma on the side of the tongue. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Tobacco (smoked or chewed), betel nut, alcohol, HPV. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Laryngeal cancer — A squamous cell carcinoma of the larynx. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Smoking and alcohol. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Oropharyngeal cancer (tonsil) — An HPV-related squamous carcinoma of the palatine tonsil, with cystic neck nodes. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: HPV 16 (most cases today), smoking, alcohol. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Thymoma — A lobulated thymoma growing from the thymus in the anterior mediastinum. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Unknown; linked with myasthenia gravis. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Lymphoma (lymph node) — A lymph node replaced and swollen by lymphoma, joined by its neighbours. Stages: Early (in the node); Stage I — one node region; Stage II — two regions on one side of the diaphragm; Stage III — both sides of the diaphragm; Stage IV — beyond the lymph nodes. Causes and risks: EBV (Hodgkin, Burkitt), HIV, H. pylori (gastric MALT), immune suppression. Drawn on the real organ from the Human Reference Atlas. (adult organ)
Splenic lymphoma — Pale lymphoma nodules in an enlarged spleen. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Hepatitis C (marginal zone lymphoma), immune suppression. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Adrenal tumour — An adrenocortical carcinoma on top of the kidney. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Mostly sporadic; Li–Fraumeni syndrome. Drawn on the real organ from the BodyParts3D atlas. (adult organ)
Neuroendocrine tumour (small bowel) — A small yellow neuroendocrine tumour of the ileum with large mesenteric nodes. Stages: Stage 0 — carcinoma in situ; Stage I — small and confined; Stage II — larger or deeper; Stage III — regional lymph nodes; Stage IV — distant metastases. Causes and risks: Mostly sporadic; MEN1. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

Dermatology & plastic surgery 9

Skin cancers (melanoma, BCC, SCC) — A skin block with a lesion: benign compound naevus, melanoma in situ (junctional and pagetoid melanocytes), invasive melanoma with a Breslow-depth ruler, basal cell carcinoma (palisading basaloid nests with retraction clefts and ulceration) or squamous cell carcinoma (keratinising nests with pearls). (block ≈ 5 mm)
Basal cell carcinoma — Nests of basaloid cells with peripheral palisading and retraction clefts under an ulcer. (block ≈ 5 mm)
Squamous cell carcinoma (skin) — Invasive keratinising nests with keratin pearls and inflammation. (block ≈ 5 mm)
Benign naevus (mole) — A compound naevus with nests that mature as they descend. (block ≈ 5 mm)
Psoriasis & eczema (epidermis) — The epidermis in inflammatory skin disease: psoriasis (thick epidermis with long rete ridges, parakeratosis, Munro microabscesses, lost granular layer, dilated capillaries) or eczema (spongiosis with lymphocytes). (epidermis 0.1–1 mm)
Eczema (spongiotic dermatitis) — Intercellular oedema forming spongiotic vesicles with lymphocytes in the epidermis. (epidermis 0.1–1 mm)
Burn depth — A burn through skin by depth — superficial, superficial partial (blister), deep partial, full thickness (eschar) or fourth degree — with Jackson's zones of coagulation, stasis and hyperaemia and thrombosed dermal vessels. (skin ≈ 2–4 mm)
Full-thickness burn — Charred eschar over coagulated dermis with thrombosed vessels. (skin ≈ 2–4 mm)
Wound healing stages — A skin incision through the four phases of healing: haemostasis (clot, fibrin, platelets), inflammation (neutrophils then macrophages), proliferation (granulation tissue with capillary loops, fibroblasts and a migrating epithelial tongue under the scab) and remodelling (flat scar of parallel collagen). (wound ≈ 1–5 mm)

Ophthalmology 10

Eye (sagittal section) & eye disease — An eyeball cut in half along its axis: cornea, anterior chamber, iris, lens with zonules and ciliary body, vitreous, retina, choroid, sclera, macula and optic nerve. Conditions include cataract, glaucoma (cupping), angle closure, retinal detachment, keratoconus, myopia and hyperopia (with focusing light rays), diabetic retinopathy and AMD. (eye ≈ 24 mm)
Cataract — An opaque, yellowed lens. (eye ≈ 24 mm)
Glaucoma (eye) — Enlarged optic cup from loss of nerve fibres. (eye ≈ 24 mm)
Retinal detachment — Retina lifted off the pigment epithelium by subretinal fluid. (eye ≈ 24 mm)
Myopia (refraction) — A long eye focusing light in front of the retina. (eye ≈ 24 mm)
Fundus (retina) view — The back of the eye as seen with an ophthalmoscope: optic disc and cup, macula and fovea, arterioles and venules. Conditions: diabetic retinopathy, hypertensive retinopathy, papilloedema, glaucomatous cupping, central retinal artery or vein occlusion, macular degeneration. (fundus ≈ 30 mm)
Diabetic retinopathy (fundus) — Microaneurysms, blot haemorrhages, hard exudates, cotton-wool spots and new vessels at the disc. (fundus ≈ 30 mm)
Papilloedema (fundus) — A swollen optic disc with blurred margins and haemorrhages — raised intracranial pressure. (fundus ≈ 30 mm)
Central retinal artery occlusion — A pale retina with a cherry-red spot at the fovea. (fundus ≈ 30 mm)
Cataract (real eye) — An opaque, yellow-white lens behind the cornea. Drawn on the real organ from the BodyParts3D atlas. (adult organ)

ENT (otolaryngology) 3

Ear (coronal section) & ear disease — The ear in the temporal bone: external canal, tympanic membrane, malleus, incus and stapes, middle ear, Eustachian tube, cochlea, vestibule and semicircular canals with the facial and vestibulocochlear nerves. Conditions: acute otitis media, otitis media with effusion, perforation, cholesteatoma, grommet, otosclerosis. (middle ear ≈ 15 mm)
Acute otitis media — A red, bulging eardrum with pus in the middle ear. (middle ear ≈ 15 mm)
Glue ear (otitis media with effusion) — A retracted eardrum with amber fluid and bubbles behind it. (middle ear ≈ 15 mm)

Obstetrics & gynaecology 5

Uterus & adnexa (gross) — fibroids, endometriosis, pregnancy — The uterus opened in the coronal plane with tubes and ovaries: fibroids (submucosal, intramural, subserosal, pedunculated), adenomyosis, endometrial polyp, endometrial carcinoma, early pregnancy, tubal ectopic pregnancy, endometriosis with an endometrioma, or polycystic ovaries. (uterus ≈ 8 cm)
Ectopic pregnancy — A gestational sac in the ampulla of the tube with haemoperitoneum. (uterus ≈ 8 cm)
Endometriosis — Powder-burn implants on the pelvic organs and a chocolate cyst of the ovary. (uterus ≈ 8 cm)
Polycystic ovaries — Enlarged ovaries with a ring of peripheral follicles. (uterus ≈ 8 cm)
Cervical intraepithelial neoplasia (CIN 1–3) — The cervical transformation zone with dysplasia climbing through the squamous epithelium: CIN 1 (lower third), CIN 2 (two-thirds) or CIN 3 (full thickness), with abnormal mitoses and inflammation. (epithelium ≈ 0.3 mm)

Dentistry & oral surgery 17

Tooth in its socket (molar section) — A lower first molar cut through its roots: enamel, dentine, pulp horns and canals, cementum, periodontal ligament, alveolar bone (cortex, trabeculae, marrow), the inferior alveolar nerve, artery and vein, and the gingiva. (lower first molar, about 22 mm tall)
Gingivitis — Plaque along the gum line and swollen, red, rounded gingiva — the bone and ligament are still intact (reversible). (lower first molar, about 22 mm tall)
Early caries (enamel lesion) — A cone of demineralised enamel in the central fissure and a chalky white-spot lesion on the side of the crown, before any cavity. (lower first molar, about 22 mm tall)
Dental caries (into dentine) — An occlusal cavity through the enamel with soft brown infected dentine beneath it and a paler translucent zone ahead of it. (lower first molar, about 22 mm tall)
Deep caries with pulpitis — Caries that has reached the pulp horn: the pulp is inflamed and engorged. (lower first molar, about 22 mm tall)
Periapical abscess — A necrotic pulp from deep caries; pus and granulation tissue destroy the bone round the root apex and drain through a sinus tract to a gum boil. (lower first molar, about 22 mm tall)
Periodontitis — Supragingival and subgingival calculus, a deep periodontal pocket, inflamed gingiva and horizontal bone loss with an angular defect. (lower first molar, about 22 mm tall)
Gum recession and cervical abrasion — The gum and bone have drawn back, baring the root surface, with a wedge-shaped abrasion notch at the neck of the tooth. (lower first molar, about 22 mm tall)
Tooth wear (attrition and erosion) — Cusps ground flat through the enamel, with cupped hollows where the softer dentine is exposed. (lower first molar, about 22 mm tall)
Cracked tooth — A stained crack running from the central fossa through the crown and pulp chamber towards the furcation. (lower first molar, about 22 mm tall)
Root canal treated tooth with crown — The canals filled with gutta-percha, a post in the distal canal, a composite core and a metal–ceramic crown on the prepared tooth. (lower first molar, about 22 mm tall)
Amalgam filling — An occlusal amalgam restoration along the central and lingual grooves, over a liner. (lower first molar, about 22 mm tall)
Composite filling — A tooth-coloured composite restoration bonded into an occlusal cavity. (lower first molar, about 22 mm tall)
Impacted wisdom tooth — A mesioangular impacted lower third molar wedged against the second molar, half in bone, with its follicle and an inflamed gum flap. (lower first molar, about 22 mm tall)
Extraction socket with blood clot — The empty socket after an extraction, filled by a blood clot that heals into new bone. (lower first molar, about 22 mm tall)
Dry socket (alveolar osteitis) — The clot has been lost: bare bone lines the socket, with food debris. (lower first molar, about 22 mm tall)
Peri-implantitis — Inflammation round a dental implant: a saucer of lost bone exposing the threads, biofilm and calculus on them, and a deep, inflamed pocket. (implant 4.3 × 11.5 mm)

Orthopaedics & rheumatology 40

Knee joint (coronal section) — The knee cut in the coronal plane: femur, tibia and fibula with cortex, trabeculae and marrow, articular cartilage, both menisci, the cruciate and collateral ligaments, and the capsule lined by synovium. (adult knee, about 20 cm of bone)
Osteoarthritis of the knee — Medial cartilage worn through to polished (eburnated) bone, joint space narrowed into varus, osteophytes at the margins, subchondral sclerosis and cysts, and an extruded, frayed meniscus. (adult knee, about 20 cm of bone)
Rheumatoid arthritis of the knee — Thick inflamed synovium (pannus) creeping over the cartilage and eating into the bone at the margins, with uniform cartilage thinning, an effusion and thinned trabeculae. (adult knee, about 20 cm of bone)
Gout of the knee — Chalky urate tophi in the synovium and at the joint margins, a punched-out erosion, needle-shaped urate crystals on the cartilage, synovitis and an effusion. (adult knee, about 20 cm of bone)
Pseudogout (CPPD) of the knee — Calcium pyrophosphate crystals laid down in the cartilage and menisci (chondrocalcinosis), with synovitis and an effusion. (adult knee, about 20 cm of bone)
Septic arthritis of the knee — Pus fills the joint, the synovium is swollen and red, and the cartilage is being destroyed in patches. (adult knee, about 20 cm of bone)
Meniscal tear (bucket handle) — The inner rim of the medial meniscus has split away and flipped into the intercondylar notch. (adult knee, about 20 cm of bone)
ACL tear — The anterior cruciate ligament torn mid-substance into two frayed stumps, blood in the joint and bone bruises on the lateral femoral condyle and tibial plateau. (adult knee, about 20 cm of bone)
Osteochondritis dissecans — A fragment of cartilage and bone separating from the medial femoral condyle. (adult knee, about 20 cm of bone)
Osteosarcoma of the distal femur — A malignant bone tumour in the distal femoral metaphysis breaking through the cortex into a soft-tissue mass, with sunburst spicules, Codman triangles and areas of haemorrhage. (adult knee, about 20 cm of bone)
Fracture patterns — A long-bone shaft broken in the pattern of your choice, as separate fragments with jagged fracture faces open on to the marrow, torn periosteum and a fracture haematoma. (adult long bone, shaft about 25 mm across)
Transverse fracture — A fracture straight across the shaft, slightly displaced and angulated, with a haematoma. (adult long bone, shaft about 25 mm across)
Spiral fracture — A twisting-injury fracture that spirals round the shaft and ends in a vertical step. (adult long bone, shaft about 25 mm across)
Comminuted fracture — The shaft shattered into main fragments, a butterfly fragment and smaller pieces, in a large haematoma. (adult long bone, shaft about 25 mm across)
Segmental fracture — Two fractures at different levels, leaving a free segment of shaft between them. (adult long bone, shaft about 25 mm across)
Greenstick fracture — A child's bone bent and cracked on its convex side, still intact on the other, under a thick periosteum. (adult long bone, shaft about 25 mm across)
Open (compound) fracture — An oblique fracture whose proximal fragment has come out through the muscle, fat and skin. (adult long bone, shaft about 25 mm across)
Pathological fracture — A fracture through bone weakened by a lytic metastasis that has destroyed the cortex. (adult long bone, shaft about 25 mm across)
Stress fracture — A hairline crack part-way across the cortex with a periosteal reaction over it. (adult long bone, shaft about 25 mm across)
Fracture healing — A shaft fracture through the stages of healing: haematoma, soft (fibrocartilage) callus, hard (woven bone) callus and remodelling. (adult long bone, shaft about 25 mm across)
Osteomyelitis — Chronic bone infection: a dead sequestrum in pus inside the shaft, wrapped by new periosteal bone (involucrum) with draining holes (cloacae). (adult long bone, shaft about 25 mm across)
Paget's disease of bone — An enlarged, bowed bone with a thick, coarse, tunnelled cortex and coarse trabeculae. (adult long bone, shaft about 25 mm across)
Simple bone cyst — A fluid-filled cyst in the metaphysis of a child's bone, thinning and swelling the cortex, with a fallen fragment at its floor. (adult long bone, shaft about 25 mm across)
Osteochondroma — A bony outgrowth continuous with the cortex and marrow of the host bone, pointing away from the joint, with a cartilage cap. (adult long bone, shaft about 25 mm across)
Rickets — A bowed bone with a widened, disordered growth plate, a flared, cupped metaphysis and sparse trabeculae. (adult long bone, shaft about 25 mm across)
Lumbar spine (L3–L5, sagittal section) — Three lumbar vertebrae cut down the middle: bodies with cortex, trabeculae and red marrow, discs with layered annulus and nucleus, the dural sac with the cauda equina, exiting nerve roots and ganglia, and the longitudinal ligaments and ligamenta flava. (lumbar spine L3–L5, about 12 cm)
Osteoporotic vertebral compression fracture — The front of L4 crushed into a wedge, its trabeculae compacted, in thin osteoporotic bone. (lumbar spine L3–L5, about 12 cm)
Lumbar disc herniation — The nucleus pulposus of L4–5 extruded through a posterolateral tear in the annulus, pressing on the L5 nerve root. (lumbar spine L3–L5, about 12 cm)
Degenerative disc disease and spondylosis — A collapsed, dehydrated L4–5 disc with fissures, osteophytes lipping the endplates and enlarged facet joints. (lumbar spine L3–L5, about 12 cm)
Lumbar spinal stenosis — A narrowed canal at L4–5 from a bulging disc, thickened ligamentum flavum and enlarged facets, pinching the dural sac and cauda equina. (lumbar spine L3–L5, about 12 cm)
Spondylolisthesis — L4 slipped forward on L5 through a break in the pars interarticularis, the loose arch left behind. (lumbar spine L3–L5, about 12 cm)
Ankylosing spondylitis (bamboo spine) — Squared vertebral bodies joined by syndesmophytes (ossified outer annulus) and an ossified anterior longitudinal ligament. (lumbar spine L3–L5, about 12 cm)
Schmorl's node — Nucleus pulposus herniated vertically through the endplate into the body of L4, ringed by sclerotic bone. (lumbar spine L3–L5, about 12 cm)
Spinal metastasis with cord compression — A lytic metastasis destroying the body of L4 and growing into the canal, compressing the dural sac. (lumbar spine L3–L5, about 12 cm)
Osteoporosis (trabecular bone) — Two cubes of trabecular bone side by side: healthy (thick, connected plates) and osteoporotic (thin, perforated and broken rods). (cubes about 10 mm)
Hip joint (coronal section) — The hip cut through the centre of the head: trabeculae along the compressive and tensile stress lines with Ward's triangle between them, cartilage, labrum, fat pad, ligament of the head and the thick capsule. (adult hip, about 25 cm)
Avascular necrosis of the femoral head — A wedge of dead bone in the weight-bearing dome of the head, bounded by a sclerotic rim, with a subchondral fracture and early collapse. (adult hip, about 25 cm)
Osteoarthritis of the hip — Superolateral cartilage loss, subchondral sclerosis and cysts in the head and acetabular roof, and osteophytes round the head–neck junction and the rim. (adult hip, about 25 cm)
Femoral neck fracture (subcapital) — A displaced subcapital fracture: the shaft rides up and rotates while the head stays in the socket, with a haematoma inside the capsule. (adult hip, about 25 cm)
Intertrochanteric fracture — An extracapsular fracture from the greater to the lesser trochanter, with the lesser trochanter broken off and the shaft displaced. (adult hip, about 25 cm)

Cancer biology & carcinogenesis 14

DNA damage by carcinogens — A stretch of B-DNA showing the lesion each kind of carcinogen leaves: tobacco smoke, aflatoxin, ultraviolet light, nitrosamines, reactive oxygen, ionising radiation, cisplatin, alcohol and aristolochic acid. (DNA 2 nm across)
Benzo[a]pyrene–DNA adduct (tobacco smoke) — A bulky benzo[a]pyrene diol epoxide bound to guanine in the minor groove — the signature lesion of tobacco smoke, causing G→T mutations in TP53. (DNA 2 nm across)
Aflatoxin B1–guanine adduct (mouldy grain) — Aflatoxin epoxide from Aspergillus-contaminated food bound to N7-guanine, stacked into the helix — the cause of the TP53 codon 249 mutation in liver cancer. (DNA 2 nm across)
Thymine dimer (ultraviolet light) — Two neighbouring thymines fused by UV-B into a cyclobutane ring, kinking the helix — the C→T signature of skin cancers. (DNA 2 nm across)
O6-methylguanine (nitrosamines) — A methyl group added to guanine by nitrosamines (processed meat, tobacco); it pairs with thymine, causing G→A mutations. (DNA 2 nm across)
8-oxoguanine (oxidative damage) — Guanine oxidised by reactive oxygen species (inflammation, radiation, alcohol metabolism); it mispairs with adenine. (DNA 2 nm across)
Double-strand break (ionising radiation) — Both strands cut by ionising radiation, with staggered ends — repaired by NHEJ or homologous recombination (BRCA1/2). (DNA 2 nm across)
Cisplatin crosslink (chemotherapy) — Platinum joining two neighbouring guanines and bending the helix — how cisplatin kills dividing cancer cells. (DNA 2 nm across)
Acetaldehyde–DNA adduct (alcohol) — N2-ethylidene-guanine formed by acetaldehyde, the toxic product of alcohol metabolism. (DNA 2 nm across)
Aristolactam–adenine adduct (aristolochic acid) — A herbal toxin bound to adenine, causing A→T mutations in kidney and urinary tract cancers. (DNA 2 nm across)
Asbestos fibres — Asbestos as it is found in the lung: straight amphibole needles, curly chrysotile bundles and asbestos (ferruginous) bodies — fibres coated with beads of iron-rich protein by macrophages. (fibres 5–50 µm long)
Metastatic cascade — How a cancer spreads, left to right: cells break through the basement membrane, change into migrating cells (EMT), squeeze into a blood vessel, travel cloaked in platelets, leave the vessel at a distant site and grow into a new colony. (cells about 15 µm)
Tumour angiogenesis — A tumour cut open — living rim, hypoxic zone and necrotic core — sending out VEGF that draws new vessel sprouts from a host vessel towards it. Anti-VEGF drugs block this. (tumour about 2 mm)
Tumour heterogeneity (clonal evolution) — A tumour cut open: the founder clone in the middle and the subclones that gained further mutations around it — one invasive, one resistant to treatment. (tumour about 1 cm)

Neurological disease — cells & molecules 10

Amyloid cascade (Alzheimer's) — APP cut by β- and γ-secretase releases Aβ42, which clumps into toxic oligomers, fibrils and finally a plaque surrounded by swollen neurites and a microglial cell. (plaque about 50 µm)
Tau and neurofibrillary tangles — Tau holds microtubules together in the axon; hyperphosphorylated tau lets go, the microtubules fall apart, and tau assembles into paired helical filaments and flame-shaped tangles. (cells 10–50 µm)
α-synuclein and Lewy bodies (Parkinson's) — α-synuclein monomers misfold into oligomers and fibrils that pile up as a Lewy body — a dense core in a paler halo — in a pigmented dopaminergic neuron of the substantia nigra. (cells 10–50 µm)
Demyelination (multiple sclerosis) — A myelinated axon and its oligodendrocyte; in an MS attack, T cells and macrophages strip the myelin and leave debris; later thin new myelin may cover the gap. (cells 10–50 µm)
Neuronal inclusions in neurodegeneration — The inclusion that marks each neurodegenerative disease, inside a neuron with a see-through cell body. (cells 10–50 µm)
Prion disease (CJD) — Normal prion protein (α-helical) is converted by contact with the misfolded form (β-sheet), which forms amyloid fibrils and riddles the brain with vacuoles (spongiform change). (cells 10–50 µm)
Excitotoxicity (glutamate synapse) — A glutamate synapse; when glutamate builds up (stroke, ALS), NMDA receptors let calcium flood in and the mitochondria swell — the neuron dies. (cells 10–50 µm)
Neuromuscular junction and myasthenia gravis — A motor nerve terminal on the muscle end-plate with its junctional folds and acetylcholine receptors; in myasthenia gravis, antibodies destroy the receptors and flatten the folds. (cells 10–50 µm)
Microglia: resting to activated — The brain's immune cells side by side: resting and ramified, reactive with thick processes, and amoeboid, eating debris. (cells 10–50 µm)
Nerve degeneration (Wallerian, Guillain–Barré) — After a nerve is cut the distal axon breaks up and its myelin forms ovoids cleared by macrophages (Wallerian degeneration); in Guillain–Barré syndrome macrophages strip the myelin instead. (cells 10–50 µm)