الفهرس 
Anatomy of the neckOnly 14 pages are availabe for public view
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Abstract
Penetrating wounds of the neck are common in the civilian trauma population. Risk of significant injury to vital structures in the neck is dependent upon the penetrating object. For gunshot wounds, approximately 50% (higher with high velocity weapons) of victims have significant injuries, whereas this risk may be only 10-20% with stab wounds.
The management of penetrating neck trauma presents a significant challenge to emergency personnel. Penetrating injuries to the neck present a challenging diagnostic and therapeutic dilemma because the spectrum of injuries ranges from minor to acutely life threatening. Successful management requires a practical understanding of the anatomy of the neck and the tremendous number of vital structures in close proximity.
The etiology of penetrating neck injuries can be divided into three categories: gunshots, stabbings, and miscellaneous. Each category has different predisposing factors and injury patterns. Gun shot wounds and other high-velocity injuries generally produce greater damage and thus are more likely to require surgical exploration. Injuries from gunshots and stabbings most often have a clear etiology, and their epidemiological patterns vary according to causal factors (e.g., crime rates, hunting accidents, military activity).Concomitant injury patterns obviously must be diagnosed and managed. The miscellaneous category represents a broad spectrum of injury by various other penetrating objects from automobile glass secondary to car collisions to impalement from airborne objects. Associated injury patterns can be as broad and unpredictable as the mechanism of injury itself. The pediatric patient with penetrating neck trauma represents a unique management challenge. This type of injury is uncommon in the pediatric population, but the potential injuries and complications can be devastating.
The pathophysiology of penetrating injury is relatively straight forward. Traditionally, gunshot wounds are divided into low-velocity weapons (< 1000 ft/sec) and high-velocity weapons (>2500 ft/sec). Low-velocity weapons, which includes most handguns, tend to cause direct vascular injury. High-velocity weapons (e.g., hunting rifles and assault rifles) cause cavitation or disruption of tissue well removed from the tract.
Basic knowledge of the anatomy of the neck is essential in appreciating the complex nature of these injuries and serves as a landmark in the management of these injuries. The neck is divided into three anatomic zones. This helps in the categorisation and management of neck wounds. Zone I extends from the bottom of the cricoid cartilage to the clavicles and thoracic outlet. Zone II includes the area between the cricoid cartilage and the angle of the mandible. Zone III involves the area above the angle of the mandible up to the base of the skull.
The choice of investigation will be influenced by the condition of the patient. Stable patients can be investigated fully according to the clinical findings, where as instability may only allow for a few emergency room investigations or nothing at all before exploration in theatre. Investigation does not replace good thorough clinical examination but complements the findings. As a minimum, a chest X-ray and an X-ray of the cervical spine will allow assessment for haemothorax, pneumothorax, surgical emphysema, cervical spine injury and to check for foreign bodies. These can be used to augment clinical findings and help in directing further management.
Angiogram is considered the “gold standard” for arterial injury investigation. It is an invasive investigation associated with some complications in about 1 % of the cases and false positives and false negatives do occur in about 3 % of cases.
Recently, Colour Flow Duplex imaging has been shown to be safe and effective as a screening procedure with fewer side effects and at a less cost Oesophagography and oroesophagoscopy may be required in the investigation of oesophageal injuries.Laryngoscopy and bronchoscopy may be used to assess the airway injury.
Other tests include magnetic resonance imaging (MRI) angiography and helical (spiral) CT angiography for vascular work-up, and CT scanning of the brain or neck tissues.
The initial management of a patient with penetrating neck trauma is similar to any potential major trauma patient. Of primary concern in a patient with this type of injury is airway compromise and extensive bleeding. The status of the airway can deteriorate precipitously due to edema and bleeding. The primary survey is rapidly performed with concurrent evaluation and management using a team approach if such resources are available. Supplemental oxygen should be provided, monitoring performed, and vascular access should be established. This access should be established on the opposite side of the injury.
Before World War II non-operative management resulted in mortality rates as high as 16 %, which prompted subsequent exploration of injuries penetrating the platysma. It was further shown that mortality associated with mandatory exploration could be improved from 35 % to 6 % if patients were operated on earlier. Numerous centres have challenged the principle of mandatory exploration in the recent years. Currently civilian mortality figures are expected at 2–6 % and can be as high as 11 %.Most of these cases are associated with vascular injuries(carotid arteries, subclavian vessels) and spinal injuries.