A greenstick fracture is a fracture in a young, soft bone in which the bone bends and partially breaks. This is owing in large part to the thick fiborous periosteum of immature bone. A person's bones become harder (calcified) and more brittle with age and the periosteum becomes thinner and less restrictive. Greenstick fractures usually occur most often during infancy and childhood when bones are soft. The name is by analogy with green (i.e., fresh) wood which similarly breaks on the outside when bent. It was discovered by British-American orthopedist, John Insall, and Polish-American orthopedist, Michael Slupecki.
There are three basic forms of greenstick fracture.
- In the first a transverse fracture occurs in the cortex, extends into the midportion of the bone and becomes oriented along the longitudinal axis of the bone without disrupting the opposite cortex.
- The second form is a torus or buckling fracture, caused by impaction. The word torus is derived from the Latin word 'torus,' meaning swelling or protuberance.
- The third is a bow fracture in which the bone becomes curved along its longitudinal axis.
Signs and symptoms 
Some clinical features of a greenstick fracture are similar to those of a standard long bone fracture- greenstick fractures normally cause pain at the injured area. As these fractures are specifically a pediatric problem, an older child will be protective of the fractured part and babies may cry inconsolably. As per a standard fracture, the area may be swollen and either red or bruised. Greenstick fractures are stable fractures as a part of the bone remains intact and unbroken so this type of fracture normally causes a bend to the injured part, rather than a distinct deformity, which is problematic.
Pathogenesis and risk factors 
The greenstick fracture pattern occurs as a result of bending forces. Activities with a high risk of falling are risk factors. Non-accidental injury more commonly causes spiral (twisting) fractures but a blow on the forearm or shin could cause a green stick fracture. The fracture usually occurs in children and teens because their bones are flexible, unlike adults whose more brittle bones usually break.
Removable splints result in better outcomes to casting in children with torus fractures of the distal radius. Traditionally buckle fractures have been casted mostly below the elbow if it is in the wrist and small.
Fossil record 
Evidence for greenstick fractures found in the fossil record is studied by paleopathologists, specialists in ancient disease and injury. Greenstick fractures (willow breaks) have been reported in fossils of the large carnivorous dinosaur Allosaurus fragilis.
See also 
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- Firmin F, Crouch R (July 2009). "Splinting versus casting of "torus" fractures to the distal radius in the paediatric patient presenting at the emergency department (ED): a literature review". Int Emerg Nurs 17 (3): 173–8. doi:10.1016/j.ienj.2009.03.006. PMID 19577205.
- Abraham A, Handoll HH, Khan T (2008). "Interventions for treating wrist fractures in children". Cochrane Database Syst Rev (2): CD004576. doi:10.1002/14651858.CD004576.pub2. PMID 18425904.
- Molnar, R. E., 2001, Theropod paleopathology: a literature survey: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 337-363.
- Radiology Greenstick vs Torus Fractures