NU 245 · NursingSection 2.2 · Musculoskeletal and skin disorders
Section 4 of 18
Fractures: definition, causes, classification and diagnosis
Define a fracture, explain the forces and the bone conditions that cause one, classify a break by the state of the skin, by whether it is complete and by the position of the ends, and choose the right imaging for a suspected break.
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Why this matters
A fracture is one of the commonest reasons a patient reaches an emergency or orthopaedic service, and the words used to describe it are not decoration: they set the priority. An open fracture starts a race against infection; a displaced fracture may need reduction and fixation; an incomplete fracture in a child is treated differently from a complete one in an adult. Knowing the four questions that classify a break — is the skin broken, is the break complete, have the ends moved, and what is the direction of the break — turns a long handover sentence into a plan. It also protects you from the most dangerous assumption in fracture care: that a normal X-ray means no fracture.
What you need to know first
You need only everyday experience: a fall can break a bone, a broken bone hurts and swells, and a wound near a break is more worrying than intact skin. Every term used here — closed, open, incomplete, complete, displaced — is defined below, so no previous orthopaedic course is assumed.
Words to know (5)
Fracture
A break in the continuity of a bone; the break may be partial or complete, and the skin over it may be intact or open. A hairline crack in a rib and a badly shattered femur are both fractures, although their severity is completely different.
Closed (simple) fracture
A fracture in which the skin over the break stays intact, so the bone has never been exposed to the outside. A closed tibial fracture still bleeds and swells inside the leg, but bacteria cannot reach the bone.
Open (compound) fracture
A fracture with a break in the skin at the fracture site, even a small puncture, so bacteria and contaminants can reach the bone and infect it. A one-centimetre wound over a broken shin makes it an open fracture and an urgent surgical problem.
Incomplete (partial) fracture
A fracture in which the bone bends and breaks on one side only, so the break does not cross the whole bone. A greenstick fracture of a child’s forearm is incomplete: one side cracks while the other side bends.
Displacement
The loss of normal alignment between the broken ends of a bone; the ends may be undisplaced, partly displaced or completely out of contact. A displaced femoral fracture looks shortened and rotated because the thigh muscles keep pulling the fragments.
One idea at a timeIdea 1 / 5
In one sentence A fracture is a break in the continuity of a bone, and it happens when the force applied is greater than the bone can structurally withstand.
A fracture is a break in the continuity of bone, caused by a force stronger than the bone
The definition sounds simple, but every part of it matters at the bedside. A break in the continuity means the bone is no longer one solid lever: it may be a partial crack or a complete separation into two or more pieces, and it can happen in any bone of the body. The commonest sites are the wrist, the ankle and the hip, because these are the bones that take the load of a fall. What turns a force into a fracture is a comparison, not a fixed number. A healthy bone tolerates the force of an ordinary fall, while the same fall breaks a bone weakened by disease, and an extreme force such as a car crash or a gunshot breaks even the strongest bone. Force repeated many times, as in running, can also end in a break although no single event was violent. So when you read the word fracture, ask two questions: how much force was involved, and was this bone normal?
For example
A young man falls from a bicycle and breaks nothing, while his grandmother falls from the same height and breaks a hip, because her bone was weaker even though the force was smaller.
Pause and check yourself
What is the difference between the force that breaks a healthy bone and the force that breaks a weakened one?
Show the answer
There is no fixed force: a healthy bone needs a strong force such as a car crash, while a bone weakened by disease can break under the moderate force of an ordinary fall.
Read detailed explanations
When the bone, not the force, is the problem: stress and pathological fractures
Not every fracture follows a single violent event. A stress fracture, also called a fatigue fracture, happens in a normal bone subjected to an abnormal load: a repetitive, submaximal force applied many times, as in distance running, ballet or military training, outpaces the remodelling that repairs micro-damage, and a fine crack develops. The typical sites are the tibia, the metatarsals and the femoral neck. The pain comes on with activity and eases with rest, and the first X-ray is often normal, so the diagnosis rests on the history and on magnetic resonance imaging or a bone scan. An insufficiency fracture is the mirror image: an abnormal bone breaks under a normal load.
It occurs in bone weakened by osteoporosis or osteomalacia, by long-term corticosteroid treatment or by radiotherapy, and it classically affects the vertebrae, producing sudden back pain. A pathological fracture is a break through bone already destroyed by disease, most often a metastasis from breast, prostate, lung, kidney or thyroid cancer, but also myeloma or a primary bone tumour. It can be the first sign that cancer is present, and any patient with a known malignancy and new bone pain must be assessed for it. The clinical consequence is important: a fracture through diseased bone heals poorly, the underlying disease must be treated, and a fragility fracture in an older patient predicts a high risk of further fractures, which is why it triggers assessment and treatment rather than being dismissed as an accident of age.
Grading an open fracture: why the wound changes the whole plan
The word open is a starting point, not a full description. Surgeons grade open fractures with the Gustilo–Anderson system, which combines the size of the wound, the degree of contamination and the extent of soft-tissue and vascular injury. Type I is a wound smaller than one centimetre with little contamination; type II is a wound of one to ten centimetres with moderate soft-tissue damage; type III is extensive, and it is subdivided by whether there is enough soft tissue to cover the bone, whether a flap is needed and whether a major vessel must be repaired. The grade matters because it predicts infection and amputation risk and drives treatment: a low-grade wound may need one debridement, whereas a high-grade injury needs repeated surgical debridement, broad-spectrum intravenous antibiotics and often vascular surgery.
The mechanism becomes clear once you know that bone has no useful defence of its own. When the skin is broken, bacteria are implanted directly into dead tissue and stripped bone; the bone ends and the surrounding muscle have lost their blood supply, so immune cells and antibiotics cannot reach them, and bacteria form a biofilm on the dead bone that no antibiotic can penetrate. That is why dead and contaminated tissue must be cut away, why the wound is covered with a sterile dressing rather than repeatedly opened for inspection, why tetanus prophylaxis is checked, and why antibiotics are given within the first hour rather than after the X-ray.
Closed fractures are described in a parallel language: the AO/OTA classification records which bone, which segment, the pattern of the break and its severity, giving surgeons and registries one shared vocabulary.
Choosing the image, and the neurovascular check that goes with it
Imaging is chosen by the question being asked, not by habit. A plain radiograph remains the first test: it is fast, inexpensive and shows bone and the position of fragments well, and standard practice is at least two views including the joint above and the joint below the injury. Its weakness is soft tissue, bone marrow and very fine cracks. Computed tomography answers questions about complex and intra-articular fractures, the spine and the pelvis, because thin slices and reconstructions show the exact path of a break and help plan the operation. Magnetic resonance imaging is the most sensitive test for bone marrow, cartilage, ligaments, tendons and an occult fracture, but it takes longer, and some implants and pacemakers make it unsafe.
Radionuclide scintigraphy surveys the whole skeleton in one examination and is useful for stress fractures and suspected metastases; a tracer is injected and the images are taken a few hours later, which is why it takes two visits — the injection visit and the imaging visit. Ultrasound is used mainly in children and for superficial structures, and it does not replace radiography. Whatever the image shows, the nurse performs the part of the assessment that no scanner can: the limb is splinted in the position found and never straightened for comfort, rings and watches are removed before swelling begins, the limb is elevated, analgesia is given, and the distal neurovascular status is recorded and repeated.
A limb that becomes painful out of proportion to the injury, pale, pulseless, numb or paralysed may have a compartment syndrome or a damaged vessel, and that finding is reported immediately rather than at the end of the shift.
Explore the diagram
Look at the whole drawing first. Then select one numbered part and connect it to the idea you just read.
From one broken bone to a classification
Follow the same bone through the four questions that turn a fracture into a description and a plan. Force beats the bone’s strength, so a break in its continuity begins. The skin then decides the first branch: intact skin is a closed fracture, and a broken skin is an open fracture with an infection risk. Inside that branch, the break is incomplete or complete, and a complete break is undisplaced or displaced. The last question is how the break is seen: an X-ray first, then MRI, CT or a bone scan when the film does not explain the pain.
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01 / 5Definition: force against bone strength
If the drawing is wider than this panel, scroll it sideways. Labels stay readable; the numbered explanations below show the same ideas.
Definition: force against bone strength
A fracture is defined as a break in the continuity of bone, whether the break is a partial crack or a complete separation. The decisive comparison is between the force applied and the strength of the bone: the same fall that leaves a healthy bone intact can break a bone weakened by disease, and a force repeated many times can end in a crack without any single violent event.
Schematic decision aid, not a scoring system: the four questions are shown in the order they are usually asked, and the plate does not show the named fracture patterns in detail or the grading of open fractures, which are taught in the following sections.
Key points to remember
✓A fracture is a break in the continuity of bone, partial or complete, caused when the force applied exceeds the bone’s breaking point.
✓Severity follows the force and the quality of the bone: a slight overload cracks it, an extreme force shatters it, and a weakened bone breaks under an ordinary fall.
✓A closed fracture leaves the skin intact; an open fracture breaks the skin, even through a small wound, and that wound is what makes infection and emergency surgery likely.
✓An incomplete fracture bends and breaks on one side only and is common in children; a complete fracture separates the bone and is then described by displacement and by the direction of the break.
✓An X-ray confirms most fractures but can miss a fine crack, so MRI, CT or a bone scan is used when the clinical findings are convincing; the limb is immobilised and never straightened to test it.
Go deeper
Worked example
A normal X-ray, a painful wrist: reasoning through a suspected fracture. A 22-year-old student slips on a wet floor and lands on her outstretched right hand. Her wrist is swollen and painful and she cannot grip. The X-ray report says: “No fracture seen.” She is tender over one small bone at the base of the thumb, and the pain is worse when she tries to use the hand.
Start from the definition. A fracture is a break in the continuity of bone, and the break may be partial. Pain, swelling and a clear mechanism mean the clinical suspicion is a fracture even before the image is interpreted; the definition does not require the bone to be in two pieces.
Classify what you can already see. The skin is intact, so this is a closed fracture and infection is not the immediate concern. The force was moderate, so an incomplete crack is plausible. Nothing about the position of the fragments can be decided without imaging.
Respect the limit of the X-ray. A plain film shows bone well but can miss a fine crack, particularly in a small bone that other bones overlap on the image. The report “no fracture seen” describes the film, not the patient.
Choose the next step. The wrist is immobilised in the position found and the patient is not sent away to see how it goes. Depending on local practice, the X-ray is repeated after one to two weeks, when bone resorption has made the crack visible, or magnetic resonance imaging or a bone scan is arranged now to detect it earlier.
Do not test the injury by moving it. The nurse checks the hand below the wrist — colour, warmth, pulse, sensation and movement — keeps the limb elevated, removes rings before the swelling increases, gives the prescribed analgesia, and explains to the patient why a normal X-ray does not yet mean a normal wrist.
The classification questions and the imaging questions work together. The state of the skin, the completeness of the break and the position of the ends tell you what the injury is and how urgently it must be treated; the imaging tells you which of those descriptions is true. When the two disagree, the clinical findings come first: a patient with a convincing mechanism, focal tenderness and loss of function is treated as having a fracture until proved otherwise.
Common misconception
Many beginners believe that an open fracture means the bone end is visibly sticking out of the skin, and that a wound which is small or clean is therefore “only” a closed fracture. In fact an open fracture is defined by any break in the skin at the fracture site, however small it looks. The reason this matters is mechanical: the wound is a doorway. Once bacteria are inside, they reach dead and stripped bone that has almost no blood supply, so immune cells and antibiotics penetrate it poorly and infection can destroy the bone. A one-centimetre puncture wound therefore changes the whole plan, from a cast to wound cover, intravenous antibiotics and surgical cleaning.
Check your reasoning
Two patients have an identical fracture of the tibia. One has a one-centimetre puncture wound at the fracture site, the other has intact skin. Using the words closed and open, explain why their risks and their treatment differ.
Reveal an answer
The patient with intact skin has a closed fracture: the bone has not been exposed to the outside, so the problems are pain, bleeding inside the limb and the position of the fragments. The patient with the puncture wound has an open fracture, because an open fracture is defined by any break in the skin at the fracture site, however small. That wound is a doorway: bacteria and contaminants reach the bone, and infected bone is hard to treat because dead or stripped bone has little blood supply and antibiotics reach it poorly. The second patient therefore needs wound cover, intravenous antibiotics and surgical cleaning, and the wound is covered rather than repeatedly inspected; the first usually needs reduction, immobilisation and pain control.
Where this comes from
MUSCULOSKELETAL SYSTEM PATHOLOGIES lecture notes (supplied), Level 200 nursing · Lines 103–132: the definition of a fracture as a break in the continuity of bone and the force-versus-resistance mechanism, severity in proportion to the force, the classification into simple/closed, compound/open, incomplete/partial and complete, the list of fracture types, and the diagnostic tests (X-ray, MRI, CT scan and bone scan). Lines 134–150 (management) were used only for the statement that the broken bone is not to be moved or straightened. The notes misspell “fracture” as “fractre” and “frature”; the spelling is corrected here. The notes give no detail for CT scan and no units or grade for bone-scan timing beyond the two-visit description, so those points are completed from standard practice and labelled in the second source.
Beyond the supplied notes: standard trauma and orthopaedic knowledge · the stress, insufficiency and pathological mechanisms of fracture; the Gustilo–Anderson grading of open fractures and the AO/OTA classification of closed ones; biofilm formation on dead bone and why debridement is essential; the detail of computed tomography and magnetic resonance imaging; the timing of radionuclide scintigraphy; the neurovascular assessment of the limb below the injury and compartment syndrome; and the greenstick mechanism in children. The supplied notes name the tests and the fracture types but do not explain these mechanisms, which are standard and uncontroversial.
Lesson progress is saved on this device for the current learner. Practice answers stay separate and are not stored.
About this course and its sources
The musculoskeletal and neurological lessons build on the supplied Level 200 nursing notes. Reproductive, respiratory, skin and nursing-response lessons use cited external references. Diagrams are original educational schematics. Sections that go beyond the supplied notes say so in their sources. Specialist clinical and French-language editorial review remain pending.