Diaphragmatic rupture is almost always iatrogenic with variable presentation. It should be diagnosed with high suspicion index in blunt thoracic trauma cases. Muscular dystrophy is associated with diaphragmatic muscle weakness. Spontaneous pneumothorax is also common in cases of muscular dystrophy which might be asymptomatic. The knowledge of muscular dystrophy and its varied presentation including the rare presentation of spontaneous diaphragmatic rupture is very important to the clinicians. This was a case of a 9-year-old male child who presented with a semi-acute diaphragmatic hernia that was misdiagnosed as pneumothorax, and a faulty chest drain insertion was done in a background of chronic muscular dystrophy which was later repaired. Clinicians are to have a high index of suspicion in treating patients of muscular dystrophy as they are prone to have rare presentations. A placement of Ryle’s tube before placing intercostal drainage would have prevented the misdiagnosis of the pneumothorax.

膈肌破裂几乎都是医源性的，表现各异。对于胸部钝挫伤病例应高度怀疑诊断。肌营养不良症与膈肌无力有关。自发性气胸在可能无症状的肌营养不良症病例中也很常见。了解肌营养不良症及其各种表现（包括罕见的自发性膈肌破裂表现）对于临床医生来说非常重要。这是一名 9 岁男孩，因半急性膈疝被误诊为气胸，在慢性肌营养不良症背景下进行了错误的胸腔引流插入，随后进行了修复。临床医生在治疗肌营养不良症患者时应保持高度怀疑，因为他们很容易出现罕见的症状。在放置肋间引流之前放置赖尔管可以防止气胸的误诊。