Hamman&;s sign is seen in which of the following condition

PERFORATION OF OESOPHAGUS AETIOLOGY :- Perforation or the rupture of oesophagus results from: 1. Instrumental trauma, i.e. oesophagoscopy or dilatation of strictures with bougies. The common site or rupture in these cases is just above the upper sphincter; sometimes it is the lower oesophagus near the hiatus. 2. Spontaneous rupture: This usually follows vomiting and involves mostly the lower third of oesophagus. Postemetic rupture of all the layers of oesophagus is called Boerhaave syndrome. DIAGNOSIS :- Early diagnosis is imperative, as mediastinitis, resulting from rupture, can rapidly prove fatal. All patients complaining of pain in the neck or interscapular region, following an oesophagoscopy, should be suspected of a perforation. The features of cervical oesophageal rupture are pain, fever, difficulty to swallow and local tenderness, along with signs of surgical emphysema in the neck. The features of thoracic oesophageal rupture are pain, referred to the interscapular region, fever 102-104degF (39-40degC), signs of shock, surgical emphysema in the neck, crunching sound over the hea (Hamman'ssign, because of air in the mediastinum) and pneumothorax. X-rays of the chest and neck are essential. They may reveal widening of the mediastinum and retrovisceral space, surgical emphysema, pneumothorax, pleural effusion or gas under the diaphragm. Ref:- Dhingra; pg num:-342