BACKGROUND: Tension pneumothorax (TPX) is an uncommon but life-threatening condition. It is important that this uncommon presentation, managed by needle decompression, is practised by paramedics using a range of educationally sound and realistic mannequins. The objective of this study is to identify if the chest wall thickness (CWT) of training mannequins used for chest decompression is an anatomically accurate representation of a human chest. METHODS: This is a two-part study. A review of the literature was conducted to identify chest wal thickness in humans and measurement of chest wal thickness on two commonly used mannequins. The literature search was conducted using the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, and EMBASE databases from their beginning until the end of May 2012. Key words included chest wall thickness, tension pneumothorax, pneumothorax, thoracostomy, needle thoracostomy, decompression, and needle test. Studies were included if they reported chest wal thickness. RESULTS: For the literature review, 4461 articles were located with 9 meeting the inclusion criteria. Chest wall thickness in adults varied between 1.3 cm and 9.3 cm at the area of the second intercostal space mid clavicular line. The Laerdal? manikin in the area of the second intercostal space mid clavicular line, right side of the chest was 1.1 cm thick with the left 1.5 cm. The MPL manikin in the same area or on the right side of the chest was 1.4 cm thick but on the left 1.0 cm. CONCLUSION: Mannequin chests are not an accurate representation of the human chest when used for decompressing a tension pneumothorax and therefore may not provide a realistic experience.