0 a condition in which someone is able to move and bend their joints (= places where bones join such as in your fingers, at your knees, etc.) more than is usual:
His problem was hypermobility in his ligaments, causing his ribs to move out of place.
People who spend a lot of time at a desk or have hypermobility in their spine are likely to have postural problems.
Those with hypermobility syndrome can perform all sorts of amazing feats, such as bending their thumb right back until it touches their forearm, and their knees left and right as well as forwards.
