The forearm is a complex anatomical structure between the elbow and the wrist that serves an important function of the upper extremity. The forearm consists of two parallel bones, the radius and the ulna. It forms a functional unit that can be considered both as an axis and a non synovial joint (). This “joint” can be best understood in term of two “condyles”, the distal radio-ulnar joint (DRUJ) and the proximal radioulnar joint (PRUJ) (). The capsule of the elbow joint and the annular ligament stabilize the bones proximally. Distally, the bones are connected by a wrist capsule, radio-ulnar stabilizing ligaments (dorsal and volar) and a fibrocartilage articular disk (triangular fibrocartilage compex, TFCC) (). There is an interosseus membrane …show more content…
It is thicker proximally, possessing a hook-shaped end (olecranon). Towards the distal end it decreases in diameter and finally, it does not reach the wrist joint at all (radiocarpal joint). The ulna is strongly connected to the humerus and it forms an uniaxial hinge joint in the elbow with flexion-extension range of motion (). The middle third of the ulna is critical with regard to the intra-osseal vascular supply of the ulnar shaft (). The ulna is close to being straight (). There is a slight apex dorsal bow just distally from the olecranon.
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The periosteum consists of an outer fibroblast layer and an inner osteogenetic layer (cambium layer). There are blood and lymph vessels and nerves in the periosteum and it plays a critical role in bone healing. In children, periosteum has greater osteogenic potential than in adults (), which allows children’s fractures to be treated more conservatively than adults’ fractures (). In children, the periosteum separates from the bone more easily than in adults (). The periosteum initiates fracture healing, producing new bone rapidly. It is potent in filling bone defects in fracture lines. Upon injury, the strong periosteum can act as a hinge, which can make alignment worse. On the other hand, an intact periosteum that lies usually on the concave side () holds fracture parts in contact with each other and it may assist closed