Most commercial flights, however, fly at 38,000 feet above the Class B maximum height and there is not a specific speed limit imposed. BA Captain Dave Thomas stated why they fly at this height: 'This sort of altitude is a good compromise between engine efficiency and aerodynamic efficiency for jet aircraft.
The most common cause of de Quervainâs tenosynovitis is chronic overuse of the wrist. Repetitive movements day after day cause irritation and pain. One common movement that causes it is lifting a child into a car seat. Another is lifting heavy grocery bags by the handles.
Constantly lifting children can also strain the tendons in the wrist and lead to this condition. If you have De Quervain tendinitis, you may notice: 1  Pain on the back of your thumb when you make a fist, grab something, or turn your wrist.  Numbness in the thumb and index finger.