الفهرس 
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Abstract
The clavicle or collar bone is a small bone that serves as a strut between the scapula and the sternum. The clavicle consists of cancellous tissue, enveloped by a compact layer, which is much thicker in the intermediate part than at the extremities of the bone.
The clavicle begins to ossify before any other bone in the body; it is ossified from three centers, two primary centers, a medial and a lateral, for the body, which appear during the fifth or sixth week of fetal life; and a secondary center for the sternal end, which appears about the eighteenth or twentieth year, and unites with the rest of the bone about the twenty-fifth year.
Fracture clavicle in skeletally mature individuals is not uncommon as it includes up to 5 % of all fractures. The incidence of clavicular fracture decreases from age 25 to 50 years, increasing again for age more than 70 years.
The management of clavicle injuries has dramatically changed over the last decade. Classic teaching suggested that even if both ends of the clavicle were widely separated it would go on to heal. However, longitudinal studies and recent experience throughout North America and Europe have suggested that this old teaching may not be accurate.
There are several classification schemes for fractures of the clavicle, ranging from the simple to the complex. Although somewhat helpful for description, the benefit of each system in determining a treatment choice or outcome potential is limited.
Possibly the most commonly used system is that of Allman. He separated clavicle fractures into three groups:
Group I—middle third fractures
Group II—lateral third fractures
Group III—medial third fractures
The diagnosis of clavicle fracture is typically made on a single AP radiograph. Most patients with a clavicle fracture, particularly young adults, will give a history of a fall directly onto the shoulder. The majority will give a history of injury of a simple fall, fall from a height, fall during sporting activity, or a motor vehicle accident.
Clavicle fractures usually heal uneventfully, even in the presence of treatment noncompliance. For most of these fractures, initial patient counseling as to the expected result is probably the most important aspect of treatment. In contrast, certain fracture types, such as the displaced and shortened midshaft fracture or the Type II distal clavicle fracture, require special attention. When necessary, operative intervention should be based on counterbalancing the deforming forces, specifically the weight of the arm. In the face of symptomatic nonunion, bone grafting and plate fixation are effective options.
Because only about 50% of the medial end of the clavicle articulates with the manubrium, the sternoclavicular joint (SCJ) has little inherent stability. Most of its strength and stability originates from the joint capsule and supporting ligaments.
Two methods can be used to classify sternoclavicular joint subluxations and dislocations; first, the anatomic position of the injury, and second, the etiology of the problem.
Sternoclavicular joint injuries include Atraumatic subluxation and dislocation as well as traumatic subluxation and dislocation.
Without question, the computed tomography (CT) scan is the best technique to study problems of the sternoclavicular joint. It clearly distinguishes injuries of the joint from fractures of the medial clavicle and defines minor subluxations of the joint.
The majority of injuries to the sternoclavicular joint can be successfully managed by nonoperative measures. This includes most acute and chronic anterior subluxations and dislocations, traumatic posterior dislocations that are reduced acutely.
It is the chronic posterior dislocation and occasionally the acute, irreducible posterior dislocation that may require a surgical procedure.
Acromioclavicular joint injuries or separations, as they are commonly described are common sports-related injuries resulting from falls or other direct forces on the superolateral aspect of the shoulder, the true incidence of AC injury is not known, as many affected do not seek treatment.
Rockwood’s group developed the most widely accepted classification system, based on the original work of Tossy et al in 1963.
Despite sophisticated imaging modalities as ultrasonography, CT, and MRI, plain radiography continues to be the most readily available, cost-effective method for routine investigation of injuries to the AC joint.
Acromioclavicular joint injuries represent a spectrum of severity, ranging from a simple sprain of the acromioclavicular ligament with no displacement to widely displaced injuries associated with severe soft-tissue injury to the acromioclavicular ligament and the coracoclavicular ligament,. Treatment options vary according to the severity of the injury and logically reflect the associated soft-tissue involvement.