Injury to the physis or the epiphyseal plate can lead to bone growth retardation, as the vascular bed that supports physical growth originates from the epiphyseal plate.Īlthough the diaphysis and metaphysis are calcified in adults, they are weaker than in the pediatric population, leading to greenstick, torus, and plastic bending injuries. Although the walls surrounding the physis are strong, the hypertrophic zone of the physis is a weak point where fractures commonly occur. The periosteum, metaphysis, and diaphysis are strong and continuous from the metaphysis to the epiphysis, surrounding the physis to provide support. Nasal trauma most commonly leads to greenstick fractures in the pediatric population due to an unfused midline suture and the majority of cartilage composition of the nasal bones. Low subcondylar fractures are the most common and are incomplete greenstick fractures the majority of the time. There are 3 types of condylar fractures. Condylar fractures are the most common pediatric mandibular fractures, accounting for up to 55% of all mandibular fractures. For example, greenstick fractures can occur in the jaw and nose. Greenstick fractures can also occur in the face, chest, scapula, and virtually every bone in the body, but with much less frequency than long bones. This is because people brace falls with an outstretched arm, resulting in fractures to the upper extremities. Most commonly, they occur in the forearm and arm, involving either the ulna, radius, or humerus. They occur most often in long bones, including the fibula, tibia, ulna, radius, humerus, and clavicle. Ī greenstick fracture is a partial thickness fracture where only the cortex and periosteum are interrupted on one side of the bone but remain uninterrupted on the other. Ī greenstick fracture is a partial thickness fracture where only the cortex and periosteum are interrupted on one side of the bone while they remain uninterrupted on the other side. These fracture patterns include greenstick, torus, and spiral injuries, which are bending injuries rather than full-thickness cortical breaks. These and other qualities of the pediatric periosteum, as well as the increased compliance of the pediatric bone, are responsible for the unique fracture patterns seen in pediatric patients. Furthermore, the pediatric periosteum is more active, thicker, and stronger in children, which greatly decreases the chance of open fractures and fracture displacement. Due to their increased compliance, pediatric bones tend to have more bowing and bending injuries under stress that would cause a fracture in an adult bone. Therefore, prior to ossification, the majority of pediatric bone is just calcified cartilage, which is very compliant when compared to the ossified bones of adults. The calcified cartilage breaks down, allowing for vascular invasion and osteoblastic/osteoclastic bone matrix deposition and remodeling. The physis is split into 4 zones: (1) the reserve or resting zone, which is made up of hyaline cartilage (2) the zone of proliferation, which is made up of multiplying chondrocytes that arrange into lacunae (lakes) (3) the zone of hypertrophy, where the chondrocytes stop dividing and start enlarging and (4) the zone of calcification, where minerals are deposited into the lacunae to calcify the cartilage. However, long bones like the phalanges have only one physis. Long bones like the femur have 2 physes separated by a diaphysis, which is the shaft of a long bone. The physis is located towards the end of the long bone, with the epiphysis above it and the metaphysis below it. It allows for bone growth from a cartilage base, known as endochondral ossification, which differs from bone growth from mesenchymal tissue or intramembranous ossification. The physis is the growth plate in long bones, including phalanges, fibula, tibia, femur, radius, ulna, and humerus. The majority of differences between adult and pediatric skeletal systems are due to the open physis in the pediatric population, which allows for continued growth prior to skeletal maturation during puberty and adulthood. The makeup, anatomy, and histology of the pediatric skeletal system is not just a smaller version of the adult form rather, it is unique in that it allows for rapid growth and change throughout development from childhood to adulthood.
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