Signs and symptoms
Two of the symptoms of flail chest are chest pain and shortness of breath.The characteristic paradoxical motion of the flail segment occurs due to pressure changes associated with respiration that the rib cage normally resists:

During normal inspiration, the diaphragm contracts and intercostal muscles pull the rib cage out. Pressure in the thorax decreases below atmospheric pressure, and air rushes in through the trachea. The flail segment will be pulled in with the decrease in pressure while the rest of the rib cage expands. During normal expiration, the diaphragm and intercostal muscles relax increasing internal pressure, allowing the abdominal organs to push air upwards and out of the thorax. However, a flail segment will also be pushed out while the rest of the rib cage contracts.Paradoxical motion is a late sign of flail segment; therefore, an absence of paradoxical motion does not mean the patient does not have a flail segment. The constant motion of the ribs in the flail segment at the site of the fracture is extremely painful, and, untreated, the sharp broken edges of the ribs are likely to eventually puncture the pleural sac and lung, possibly causing a pneumothorax. The concern about "mediastinal flutter" (the shift of the mediastinum with paradoxical diaphragm movement) does not appear to be merited. Pulmonary contusions are commonly associated with flail chest and that can lead to respiratory failure. This is due to the paradoxical motions of the chest wall from the fragments interrupting normal breathing and chest movement.
TENEX may refer to:

TENEX (operating system)
Techsnabexport, a Russian company specializing in export of nuclear materials
Tenex, a brand name for the medication guanfacine, a sympatholytic used to treat hypertension, ADHD and Anxiety
Tenex, a brand name for .22 LR ammunition manufactured by Eley Limited and widely used in high level competition such as the ISSF World Cup and Olympic Games
10X, an alternative name for superfine powdered sugar or confectioners sugar
10x, internet slang for "thanks"; see wikt:10x

See also
TENEX C shell