Medical Diagrams, Free to Reuse With Attribution

Diagram comparing an uninjured neck, where the chin clears the chest, with a burn scar contracture, where shortened scar tissue has pulled the chin down onto the chest

How contracture forms

Contracture across the front of the neck. The scar band shortens as it matures and draws the chin toward the chest, taking the lower lip and eyelids with it.

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Why wood reads as gas

Dry wood is mostly trapped air, which is why the first report called it gas. The path on the right is why pulling it back out through the eye was ruled out.

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Cross-section diagram comparing three outcomes of wound healing: a normal scar sitting flat within the wound edges, a hypertrophic scar raised but still within the edges, and a keloid extending beyond the edges into uninjured skin

Scar types compared

The dashed lines mark the edges of the original wound. What separates a keloid from a hypertrophic scar is not how raised it is, but whether it crosses those lines.

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Schematic comparison. Left: conjoined twins, two complete bodies each with its own heart, joined at a shared region. Right: heteropagus twinning, one complete body with a heart carrying an incomplete twin that has no heart and is supplied entirely by the complete twin's circulation

Conjoined vs parasitic

The distinction that decides everything: in conjoined twinning there are two circulations, in heteropagus twinning there is one. The parasite has no pump and is entirely downstream of the autosite's heart.

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Two eyes under a camera flash compared. The left shows a normal red pupil reflex. The right shows leukocoria, a white pupil reflex, which can be the first sign of retinoblastoma

Red reflex vs leukocoria

Leukocoria often appears in one eye only, and sometimes only at certain angles, which is why it is easy to dismiss as a camera artefact.

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Chart comparing viability windows: fingers tolerate about 12 hours at room temperature and 24 hours cooled, while amputations above the wrist tolerate about 6 hours warm and 12 hours cooled

Ischaemia windows

Approximate working figures. Muscle is what shortens the window, which is why a forearm is a far more urgent problem than a fingertip.

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Free fibula flap

The free fibula flap. Norris had this done twice, once for the lower jaw and once for the upper.

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Two panels. Left: the branching network of small arteries supplying an area of skin, with a clot blocking one trunk. Right: the skin above, where the purple discolouration takes the same branching shape, because everything downstream of the clot has lost its supply

Why it is net-shaped

Retiform purpura is not a rash in the ordinary sense. It is the outline of an occluded vascular tree, seen through the skin.

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What is removed

The implant is roughly as thick as the bone it replaces, which is why the leg does not end up shorter. Simplified: the real femoral cuts include angled chamfers that the front view cannot show.

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Diagram of the trunk showing blood from the gut meeting resistance at a scarred liver and detouring by three routes: upward to veins at the lower gullet, forward through a reopened vein at the navel onto the skin, and downward to veins around the rectum

Three escape routes

The three main escape routes. Only one of them shows on the outside of the patient.

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Two panels. Normal control: a motor neuron receives both a go signal and a stop signal, so the muscle contracts and then relaxes. Tetanus: the toxin blocks the stop signal, so the motor neuron fires continuously and the muscle stays contracted

How the toxin works

The toxin does not stimulate muscles. It removes the ability to stop stimulating them.

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Two panels. Left: a vein in the limbs contains one-way valves, so blood cannot flow backwards. Right: the veins of the face and jaw have no valves, so infection at a tooth root can travel backwards up into the venous spaces inside the skull

Valveless veins

Most veins have valves that permit flow in one direction only. The veins draining the face and jaw do not.

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Timeline. A new medicine is started, then nothing happens for four days to four weeks. Then fever, sore throat and burning eyes begin, which is indistinguishable from a virus and where the diagnosis is missed. Only afterwards do raw mouth and eye lesions and peeling skin appear

The latency window

The gap between the drug and the symptoms is the whole problem. By the time anything appears, the medicine that caused it was started weeks ago.

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Two panels. Left: fungal filaments grow through the wall of a small artery into the channel inside it, where a clot forms. Right: the vessel is blocked, all tissue downstream has died, and an antifungal drug travelling in the blood cannot reach past the blockage

Angioinvasion

The tissue is not consumed. It is cut off. The same principle produces the net-shaped skin lesions seen in other vessel-blocking diseases.

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Three stages inside a stomach: individual hairs catching in the folds of the lining, then a compacted mass filling the stomach and taking its shape, then a tail of the mass extending through the stomach outlet into the small intestine

How it builds

The mass is a cast of the stomach. When a tail passes through the outlet into the small bowel, the condition is called Rapunzel syndrome.

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A foot seen from above with four levels marked. Grade one at the tip resolves after rewarming. Grade two reaches the end segment of the toe. Grade three reaches the middle and base of the toe. Grade four reaches back into the bones of the mid-foot

Cauchy grading

Read it back-to-front: the grade is how far the injury reaches, not how bad it looks.The Cauchy grading system. The grade predicts what will be lost, which is why it is recorded digit by digit.

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Timeline in hours from injury. Clot-dissolving tPA is effective within about 24 hours, iloprost within about 48 hours with this study extending toward 72. Climbers evacuated from Everest reach Kathmandu between 48 and 72 hours, outside the tPA window entirely

Treatment windows

The two bars are drug windows. The block on the right is when a climber can physically arrive.His arrival at 66 hours sits in the zone this study was testing. The treatment with the strongest evidence had expired more than two days earlier.

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Three stages of a paramedian forehead flap. A strip of forehead skin is outlined over the artery running up from the inner eyebrow, then cut free at the top and swung down over the nose while remaining attached at the brow, and finally the connecting bridge is divided once the new nose has its own blood supply

The forehead flap

The paramedian forehead flap. Described in India well over two thousand years ago and still the standard reconstruction for a missing nose.

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Two eyes compared. With eyelids, a blink spreads tears across the clear front surface, which stays transparent. Without eyelids the surface is permanently exposed, dries, and becomes cloudy and scarred

Why eyelids matter

The eye itself can be entirely healthy and the person can still go blind, because the surface in front of it has no protection.

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Three cross-sections through the eye socket. First the eyeball rests on a thin plate of bone above an air cavity. Second, with the plate removed the eyeball sinks and drops out of line. Third, a titanium mesh sling anchored to the remaining bone holds the eye at its original level

The orbital floor

The plate is thin enough to be nearly transparent on a scan, and it is the only thing holding the eye at the right height.

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Three stages. Resin is pushed into the vessels of a specimen, it hardens inside the whole branching network, and then the surrounding tissue is dissolved away in strong alkali, including the vessel walls, leaving only the solid cast

Corrosion casting

The alkali does not distinguish between the tissue and the vessels running through it. Everything organic goes.

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Three cross-sections. An artery is a tube with a hollow channel that resin can fill. A nerve is solid throughout, packed with bundles of fibres, so there is nothing to inject. The only method is to cut away every surrounding tissue by hand

Nerve vs vessel

A vessel is a container. A nerve is a cable. One can be filled; the other can only be uncovered.

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Three cut-away views of a grinder barrel. The screw drives everything toward the cutting plate. A hand pulled backwards binds against the angled flights. The only ways out are reversing the screw or cutting the barrel apart.

Why it will not come back

The flights are angled, so force applied backwards tightens the grip rather than releasing it.

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Three cross-sections of a forearm. Normally muscle sits in a sheath with open vessels and room to swell. Closed under tension, pressure rises and the vessels are squeezed shut. The dead muscle then scars and pulls the wrist and fingers into a fixed bend.

Closure under tension

The compartment cannot expand. Once the pressure inside it exceeds what the small vessels can push against, the muscle stops being perfused while everything around it still looks intact.

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Three panels. In a slow tumour only a few cells divide at any moment. In a very fast tumour almost all of them do. Because chemotherapy kills dividing cells, the same dose barely dents the slow tumour and removes most of the fast one.

Speed cuts both ways

Chemotherapy acts on cells while they divide. A tumour in which nearly every cell is dividing is the most vulnerable target there is.

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A side view of the head and chest. The temporalis muscle at the temple swings down under the cheekbone to line the inside of the mouth. The pectoralis major with its overlying skin is tunnelled up under the neck to cover the outside of the face. Each stays joined to its own artery at a pivot point.

Two pedicled flaps

A pedicled flap rotates around the vessel that feeds it. The arc of that rotation is what decides whether the tissue can reach the defect at all.

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Two patches of skin compared. In discrete smallpox the pustules sit apart with normal skin between them and about one patient in ten died. In confluent smallpox they merge, destroying the skin between them, and around six in ten died.

Discrete against confluent

The classification was not descriptive. It was the closest thing the period had to a prognosis.

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Why position mattered

Nothing was blocking his throat. The structure that normally holds it open had come away from the skull, and only his position was keeping it clear.

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Why the site decides it

The same growth, in two places. One is an operation with a good outcome and the other is a decade of pressure on a developing brain.

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Two diagrams of the route from gut to body. Normally blood from the intestine passes through the liver, where resident immune cells strip out bacteria. In cirrhosis the blood is diverted around the scarred liver, the remaining filtering cells work poorly, and free iron in the blood feeds the organisms that get through.

Why the liver decides it

Everyone at that table swallowed the same organisms. Only one of them had lost the filter that normally deals with them.

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Three panels. Normally blood arrives through an artery and leaves through veins at the same rate. After replantation the artery is repaired but the thin veins are not, so blood fills the tissue and stops moving. A leech makes an exit whose bite keeps oozing for hours, draining the tissue until new veins grow.

In, but not out

The flap was not short of blood. It was full of blood that had no way out.

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Three panels. Window glass blocks almost all ultraviolet B, the short wavelength that burns, but lets most ultraviolet A through. In the skin, ultraviolet B is spent near the surface while ultraviolet A reaches the dermis where collagen and elastic fibres sit. Decades later the surface has thickened and the fibres beneath it have been replaced by clumps of damaged elastic material.

Through the glass

The glass removed the warning, not the exposure. What got through went deepest.

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Three panels. The neck is divided into three zones, and the branch entered the highest one, between the angle of the jaw and the skull base, where the carotid artery and jugular vein run. An object left in place plugs the hole it has made in a vessel; pulled out, the hole opens. Because the stump on the left side of his neck stopped him lying flat, he was turned onto his right side and the airway was placed through the front of the neck.

Left in, on his side

The branch sat in the part of the neck that is hardest to reach, and it stayed in until someone could reach it.

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Three panels. A needle delivers a drug into or beside a small artery deep in the muscle. Inflammation damages that artery, and because it supplies one territory with no alternative route, a cone of tissue dies: the top of the muscle, the fat and the skin above it. Left open, the wound fills with granulation tissue and closes from the edges inward over about two months.

One artery, one territory

The authors describe the defect as cone-shaped. That is the shape of one artery’s territory, not the shape of a needle track.

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Three panels. The severed hand travels wrapped in saline-soaked gauze inside a sealed bag placed in an ice box, cooled but not frozen. At the hospital two teams work at once: one prepares the hand on a side table while the other resuscitates and anaesthetises the patient. The repair runs in a fixed order: bone, then the artery bringing blood in, then the veins letting it out, then nerves, tendons and skin.

Cold, then parallel, then in order

Cooling buys hours. Working on the hand and the patient at the same time buys more.

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Three panels. An implant, drawn here behind the chest muscle, sits inside a capsule of scar tissue. When the implant shell tears and the capsule gives way as well, the silicone escapes into the surrounding tissue and can track towards the armpit. In the published cases the authors reviewed, escaped silicone was found in the arm or forearm 11 times, the chest cavity 4 times, the abdominal wall 3 times, the legs twice and the back once.

How silicone travels

While the capsule holds, the silicone from a ruptured implant stays contained. Once the capsule gives way, it can travel, most often into the arm.

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Three panels. The first shows a face from the front with the torn area shaded: the forehead, the left eyebrow and eyelids, the nose, the left cheek, part of the right cheek, both lips and the chin, while the left eye itself was unharmed. The second shows a side view in which blood and loose flaps of tissue block the airway until, after suction, a breathing tube is passed. The third shows the repair order: the inner lining first with dissolving stitches, then the cartilage framework, then the skin with nylon stitches, in one operation.

Airway first, then every layer

Nothing could be repaired until he could breathe. After that, each structure went back in its own layer, starting from the inside.

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Three panels. The first compares time on the waiting list: a median of 4 months, with a range of 1 to 14, for the hospital's White face transplant recipients, against 17 months for this patient, whose first offer came at 9 months. The second shows an 18-step skin complexion scale from lightest to darkest, which he used to choose a donor, declining two before accepting one. The third shows a face with two biopsy sites, the skin and the lining of the mouth, because redness from rejection is harder to see on darker skin.

The wait, the match, the biopsies

A face is matched on tissue type like any transplant, and then on something no kidney needs: how it will look.

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$Three panels. The first shows the usual position of a bone plate, lying on the shin bone under the skin, with screws through the plate into the bone across a fracture. The second shows the plate used in this case, lying outside the leg, with six screws reaching the bone through small cuts, three above and three below the fracture, while the wound can still be dressed. The third shows why this works with a locking plate: the threaded head of each screw locks into the plate, so the bone is held at a fixed distance and the plate does not need to touch it.$

A plate inside, a plate outside

A locking plate does not need to touch the bone to hold it, which is what let it work as a frame outside the leg.

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Three panels. The first is a simplified front view of the torso showing the path of a 63.5 centimetre wooden rod that entered through the rectum and ran upward through the bowel's mesentery, the stomach, the diaphragm and the sac around the heart, ending under the right collarbone and into the neck, without cutting a major blood vessel. The second shows why an impaled object is left in place until surgery: it can plug what it has torn, so the chest and abdomen were both opened before it was moved. The third shows how it came out: cut in two inside the chest with a bone saw, each piece removed in the direction it had travelled, the upper piece through a new cut in the neck.

The path, and how it came out

Simplified. The rod crossed the pelvis, abdomen and chest, and no major blood vessel was cut along its track.

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Three panels. The first shows an electric arc jumping from a 20,000-volt switchgear to a man's hand, with branching red fern-like marks appearing on his right flank, near a wrench in his hip pocket. The second is a cross-section of skin under one red branch: small blood vessels just under the surface leak red blood cells, T cells gather, and the skin makes lactoferrin, a protein that binds the iron from the leaked cells. The third is a timeline: the marks appear at the time of injury, are gone within 24 hours, the burns elsewhere heal in 3 weeks, and he is back at work at 6 weeks.

How the pattern forms and fades

Simplified. The branches are leaked blood just under the surface, and the skin clears them within a day.

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Three panels. The first shows the severed ear on day 1: the skin is removed and only the cartilage framework, the shape of the ear, is kept. The second is a cross-section of the abdominal wall: the cartilage lies in a pocket in the fatty layer under the skin, where the surrounding tissue keeps it alive for three months. The third shows the left side of the head: the cartilage is taken out of the abdomen, placed back where the ear was and covered with skin moved from nearby, six months after the accident in all.

How the ear was saved

Simplified. The cartilage was kept alive by the tissue around it until the wound on his head had healed.

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Three panels. The first is a simplified front view of the skull showing where the attack fell: tooth furrows in the frontal bone, a broken right cheekbone, broken nasal bones and a broken upper jaw. The second is a side view showing the tooth-bearing part of the upper jaw torn away and lying loose on the tongue, leaving both maxillary sinuses open to the mouth. The third shows the repair: small titanium plates and screws on the cheekbone and nose, three loose pieces of upper jaw fixed back as landmarks, and a bone graft from the leg planned to rebuild the jaw.

What was put back

Simplified. Plates held what could be saved; the rest of the upper jaw will have to be rebuilt.

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Three panels. The first is a simplified side view of the head showing the scalp torn loose almost all the way round, a broken skull above the left ear with air inside, and a wound beside the left eye. The second is a cross-section through the layers of the head showing the scalp lifted away at its loose layer, a piece of skull pushed inwards and air beneath it. The third shows the repair: broken bone removed, the dura patched with fascia, titanium mesh over the gap in the skull, and the scalp laid back with staples over a drain.

What was torn, and how it was repaired

Simplified. The scalp separates at its loose layer; the repair rebuilt the head from the inside out.

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Where it grew, and how big

Simplified. A lipoma is called giant from 10 cm or 1 kg; this one was 60 cm and 20 kg.

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$Three panels. The first is a simplified view of a woman from behind showing what the shark attack took: her left hand, the thumb and two fingers of her right hand, a large wound across her lower back and left thigh with 16 centimetres of the sciatic nerve missing, and an open ankle fracture. The second shows the gap in the sciatic nerve bridged by the ulnar nerve from her amputated arm, carried with its own artery and covered by a flap of back muscle. The third shows her left big toe moved to her right hand to become a thumb.$