Merck Manual

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Deciphering Medical Terms for Fractures

Deciphering Medical Terms for Fractures




The broken pieces of bone are not in a straight line. One is at an angle in relation to the other.


A piece of bone is pulled off from the main part of the bone. A ligament may pull off a piece of bone if the external force is strong enough, as may occur in a fall. A tendon may pull off a piece of bone if the attached muscle contracts forcefully enough, as may occur in young athletes. Avulsion fractures usually occur in the hand, foot, ankle, knee, or shoulder.


The skin over the fractured bone is not torn.


The bone is broken into three or more pieces. Often, the bone is broken into many very small pieces. These fractures are often caused by a great force, as occurs in a car crash. They can also occur in people with osteoporosis, which weakens bone.

The bone collapses into itself. These fractures usually occur in older people (particularly those with osteoporosis). The backbones (vertebrae) are often affected (called vertebral crush fractures).


Some parts or pieces of the broken bone are separated and not in correct alignment.


The bone is partly cracked and/or bent but not completely broken through. Greenstick fractures occur only in children.

These fractures occur in the growth plate, which is made of cartilage. Growth plates enable bones to lengthen until children reach their full height. When growth is completed, growth plates are replaced by bone. When a growth plate is fractured, the bone may stop growing or grow crookedly. Growth plate fractures occur only in children and adolescents.


One end of the broken bone is jammed into the other. As a result, the bone appears shortened.

Joint (intra-articular)

Fractures may extend into the cartilage at the ends of bones that form a joint (called joint surfaces). Normally, this cartilage reduces the amount of friction that occurs when bones in a joint rub against each other. When this cartilage is fractured, people cannot move the joint as well, and osteoarthritis is more likely to develop in the joint.


The pieces of broken bone are still in place (aligned normally), and there is no space between them.


The bone is broken in a straight line diagonally across the long middle part (shaft) of the bone.


These small fractures are difficult or impossible to see on x-rays, but they may be seen on other imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI). After a few days or weeks, changes occur in the new bone that forms as the bone heals. Then occult fractures may be seen on x-rays. Some stress fractures are occult.


The skin and tissues covering the fractured bone are torn, and the bone may be sticking out of the skin. Dirt, debris, or bacteria can easily contaminate the wound and may cause an infection in the broken bone.


Osteoporotic fractures result from osteoporosis (progressive loss of bone density), which weakens bones and makes them more likely to break. Osteoporotic fractures (sometimes called fragility fractures) occur in older people, usually in the hips, wrists, spine, shoulders, or pelvis.


Pathologic fractures are caused by a disorder that weakens a bone, such as osteoporosis, certain bone infections, or bone tumors (including metastases to the bone from cancers elsewhere in the body to the bone).


There are two separate breaks in a bone. Segmental fractures are a type of comminuted fracture.

Spiral (torsion)

Spiral fractures occur when the bone is twisted apart. As a result, the ends of the bone may be sharp, jagged, and slanted.

A stress fracture occurs when force is repeatedly applied to a bone during certain activities, such as walking with a heavy pack or running. Stress fractures are often small cracks in bone (sometimes called hairline fractures). Stress fractures commonly occur in bones that bear weight, such as those of the foot or lower leg.


The bone buckles rather than breaks. Torus fractures usually occur only in children. Bones in children can buckle rather than break because their bones are more rubbery than those in adults.


The bone is broken straight across.