The following situations may result in wrist drop:

Stab wounds to the chest at or below the clavicle–The radial nerve is the terminal branch of the posterior cord of the brachial plexus. A stab wound may damage the posterior cord and result in neurological deficits, including an inability to abduct the shoulder beyond the first 15 degrees, an inability to extend the forearm, reduced ability to supinate the hand, reduced ability to abduct the thumb and sensory loss to the posterior surface of the arm and hand. Broken humerus–The radial nerve can be damaged if the humerus (the bone of the arm) is broken because it runs through the radial groove on the lateral border of this bone along with the deep brachial artery. Lead poisoning–Wrist drop is associated with lead poisoning due to the effect of lead on the radial nerve. Persistent injury–Persistent injury to the nerve is a common cause through either repetitive motion or by applying pressure externally along the route of the radial nerve as in the prolonged use of crutches, extended leaning on the elbows, or regular upper body rope suspension. The colloquial terms for radial nerve palsy are derived from this cause. Correcting dislocated shoulders–Radial nerve palsy can result from the now discredited practice of correcting a dislocated shoulder by putting a foot in the persons armpit and pulling on the arm in attempts to slide the humerus back into the glenoid cavity of the scapula.
Seated squeeze - Again in a seated position, place one hand above the belly button, and the other below the belly button. With controlled breaths, with a mid-way starting point, pull the abdominals back toward the spine, hold for 2 seconds and return to the mid-way point. Complete 100 repetitions. Head lift – In a lying down position, knees bent at 90° angle, feet flat, slowly lift the head, chin toward your chest, (concentrate on isolation of the abdominals to prevent hip-flexors from being engaged), slowly contract abdominals toward floor, hold for two seconds, lower head to starting position for 2 seconds. Complete 10 repetitions. Upright push-up – A stand-up push-up against the wall, with feet together arms-length away from wall, place hands flat against the wall, contract abdominal muscles toward spine, lean body towards wall, with elbows bent downward close to body, pull abdominal muscles in further, with controlled breathing. Release muscles as you push back to starting position. Complete 20 repetitions. Squat against the wall – Also known as a seated squat, stand with back against the wall, feet out in front of body, slowly lower body to a seated position so knees are bent at a 90° angle, contracting abs toward spine as you raise body back to standing position. Optionally, this exercise can also be done using an exercise ball placed against the wall and the lower back. Complete 20 repetitions.