Ulkokierto

Ulkokierto, or external rotation, is a movement in which a limb rotates away from the midline of the body. In Finnish anatomy and physiotherapy usage, ulkokierto describes the rotation of a joint around its long axis when the distal segment turns outward relative to the trunk. The term combines ulko- meaning external and kierto meaning rotation.

The movement occurs at several joints, most notably at the shoulder (glenohumeral joint) and the hip (acetabulofemoral joint). In these joints, ulkokierto happens when the forearm or the leg rotates laterally with respect to the trunk, and it can be performed in various positions of flexion or extension depending on the movement context and joint constraints.

Muscles responsible for external rotation vary by joint. In the shoulder, the primary external rotators are the infraspinatus and teres minor, with the posterior deltoid contributing in some positions. In the hip, the deep external rotators include the piriformis, obturator internus and externus, gemelli, and quadratus femoris, with the gluteus maximus assisting when the hip is extended.

Clinical relevance and assessment focus on the strength and flexibility of external rotation. Limited external rotation can indicate injury or pathology such as rotator cuff tendinopathy, adhesive capsulitis, or hip impingement. Rehabilitation typically emphasizes both stretching to improve ROM and strengthening to stabilize the joint. Common exercises include resistance-band external rotation and side-lying external rotation, often integrated into larger physical-therapy or athletic-training programs.

See also: internal rotation, range of motion, physical therapy, orthopedics.