Kiertäjälihasta

Kiertäjälihasta, often translated as rotator cuff muscles, refers to a group of four muscles and their tendons that surround the shoulder joint. These muscles originate from the scapula, or shoulder blade, and insert onto the humerus, the upper arm bone. The primary function of the kiertäjälihasta is to stabilize the glenohumeral joint, which is the main ball-and-socket joint of the shoulder. This stabilization is crucial for a wide range of arm movements.

The four muscles that constitute the kiertäjälihasta are the supraspinatus, infraspinatus, teres minor, and subscapularis. The supraspinatus muscle is located on the top of the shoulder blade and is primarily responsible for initiating abduction, the movement of raising the arm away from the body. The infraspinatus and teres minor muscles are located on the posterior aspect of the scapula and are key for external rotation of the arm. The subscapularis muscle lies on the anterior side of the scapula and is the primary muscle responsible for internal rotation of the arm.

Together, these muscles work synergistically to control the position of the humeral head within the glenoid cavity, preventing excessive movement and providing a stable base for the larger muscles of the shoulder and arm to perform more powerful actions. Injuries to the kiertäjälihasta, such as tears or impingement, are common and can lead to pain, weakness, and reduced range of motion in the shoulder. Rehabilitation often focuses on strengthening these muscles to improve stability and function.