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•Complete- does extend and bone breaks into atleast 2 complete sections •Spontaneous Fracture TYPES OF COMPLETE FRACTURES:bone is broken into at least two complete pieces•Comminuted–bone breaks into more than two pieces•Impacted–one fragment is driven into the cancellous portion of the other fragment •Linear–run parallel to the long axisof the bone •Transverse–at right angles to the long axis of the bone •Spiral –fracture takes a helicalcourse around the bone •Oblique –run obliquelyin relation to the long axis of the bone •Dentate –have rough, toothed and/or broken ends•Stellate–have breakage lines radiating from a central pointTYPES OF INCOMPLETE FRACTURES–do not extend completely across the bone •Greenstick –occurs on the convex side of the curve of the bone •Hairline- 2 broken sections of bone don’t separate (e.g., skull fractures) BONE REPAIR: Bone is a living tissue that can be repaired after damage is done to it. a. HEMATOMA FORMATION: (blood) HEMATOMA: a localized mass of blood released from blood vessels but confined within an organ or space. When a fracture occurs, the blood vessels in the area are broken, blood rushes into the injured area and a clot forms 6-8 hours after injury. Due to injury osteocytes around the damaged site die due to a disruption of the blood and therefore of oxygen. Inflammation occurs, bringing phagocytic cells and osteoclasts into the area to clean up the dead and dying bone cells. b. CALLUS FORMATION: (Cartilage) CALLUS: mass of tissue that forms at the fracture site and attempts to connect the broken ends of the bones. This connective tissue will be invaded by chondroblasts from the periosteum and endosteum of the broken bone. Cartilage is formed and chondoblasts become chondrocytes. –Internal- blood vessels grow into clot in hematoma. •Macrophages clean up debris, break down dead tissue, fibroblasts produce collagen and granulation tissue. •Chondroblasts from osteochondral progenitor cells of periosteum and endosteum produce cartilage. •Osteoblasts invade. New bone is formed.
–External- collar around opposing ends.This . Bone/cartilage collar stabilizes two pieces of the broken bone.c.CALLUS OSSIFICATION: (Bone)Similar to fetal development, the chondrocytes will evetually be replaced by osteoblasts and new bone will be formed. Thus Callus is replaced by cancellous bone. d.REMODELING OF BONE:The final phase of fracture repair is REMODELING of the bony callus by osteoblasts and osteoclasts.Repair may be so complete that no evidence of a break remains. However, the repaired area may remain slightly thicker. In bone remodeling there is replacement of cancellous bone and the damaged material by the compact bone. Sculpting of site is done by the osteoclasts (In order for this fracture repair to occur, the 2 portions of the broken bone must be located very near to each other and held stationery. If this is not possible, another material must be used to join the bone –