Received 5 March 2011, Accepted 24 March 2011, Available online 23 June 2011. Spontaneous pneumomediastinum is defined as free air within the mediastinum, not associated with trauma. Causes include exercise, drugs, asthma, vomiting, difficult labour and Valsalva maneuvers. Itâs a rare, usually benign and self-limited condition, more prevalent in young males.
A youth bouncing on a trampoline. A trampoline is a device consisting of a piece of taut, strong fabric stretched over a steel frame using many coiled springs. People bounce on trampolines for recreational and competitive purposes.
1 Reinforced T-sockets stabilize the upper enclosure frame to the trampoline frame and prevents structural twisting.  Stay-put enclosure net interlocks to the jumping mat by using a patented button-hole feature attaching the enclosure netting to the jumping surface at each V-ring eliminating gaps.