pöördliigestiga

Pöördliigestiga is an Estonian term describing a joint type in which one bone rotates around another along a single axis. In anatomy, this corresponds to the pivot joint, a uniaxial synovial joint that allows rotational movement around one main direction.

Pivot joints are characterized by a ring-like arrangement that permits rotation of a bone around a pivot point. The movement is primarily axial, enabling actions such as turning the head or rotating the forearm. Stability is provided by ligaments and the joint capsule, which limit excessive rotation and keep the rotating bone aligned with its partner.

The most well-known human pivot joints are the atlantoaxial joint between the first two cervical vertebrae, which allows turning the head from side to side, and the proximal radioulnar joints near the elbow, which enable forearm rotation during pronation and supination. In the atlantoaxial joint, the dens of the axis acts as the pivot around which the atlas rotates, with the ring formed by the atlas and stabilizing ligaments, including the transverse ligament, helping to secure the dens. In the forearm, the radial head rotates within a notch of the ulna and is held in place by the annular ligament.

Clinical relevance includes injuries and degenerative changes that can impair rotation, such as dislocation, subluxation, or arthritis affecting pivot joints. Understanding pöördliigestiga helps explain how certain motions are possible and why their disruption can limit movement.