De Quervain's tenosynovitis is inflammation of tendons on the side of the wrist at the base of the thumb. These tendons include the extensor pollicis brevis and the abductor pollicis longus tendons, which extend the joints of the thumb. De Quervain's tenosynovitis can be brought on by simple strain injury to the extensor pollicis longus and abductor pollicis tendons. Typical causes include stresses such as lifting young children into car seats, lifting heavy grocery bags by the loops, and lifting gardening pots up and into place.
double helix. n. The coiled structure of double-stranded DNA in which strands linked by hydrogen bonds form a spiral configuration, with the two strands oriented in opposite directions.
The double helix in DNA consists of two right-handed polynucleotide chains that are coiled about the same axis. The heterocyclic amine bases project inward toward the center so that the base of one strand interacts or pairs with a base of the other strand.r to put it more simply. The molecule of DNA has two helical (spiral) structures. Think of a ladder, grab the ends of the ladder and twist, first helix. Now take that twisted ladder and wrap it around a pole, second helix.