The function for arm movement of each muscle involved in the rotator cuff has already been described.
However, both muscles differ in their innervation: the teres minor muscle is innervated by the axillary nerve. infraspinatus thus form not only an anatomical but also a functional unit.
He also participates in pulling the upper arm towards the body (adduction). Functionally, it is a weak external twist (external rotation) of the upper arm. He also pulls to the tubercle majus on the humerus. The teres minor muscle (lat "minor": smaller, "teres": round) has its origin at the side edge of the shoulder blade below the infraspinatus muscle. The innervation occurs over the suprascapular nerve. Together with the other muscles of the rotator cuff, he stretches the capsule around the shoulder joint. When the arm is raised, however, it causes the arm to move away from the center of the body. In addition to external rotation, he is also involved in pulling the upper arm towards the middle of the body (adduction). If you look at the course of the muscle - from the shoulder blade to the lateral head of the upper arm - you can understand its function well: If the infraspinatus muscle contracts, it causes the arm to turn outward (external rotation), it is even the strongest external rotator of the upper arm. "Infra": below, "spina": spine) arises from the lower part of the rear surface of the shoulder blade, the so-called infraspinate fossa, and also extends to the tubercle majus of the humerus, somewhat behind the supraspinatus muscle. This results in pain when the arm is lifted to the side or when under stress, such as when lying on the affected arm.Īnother clinical picture is the Suprascapularis syndrome: In this case, the suprascapular nerve, which supplies both the supraspinatus and the infraspinatus, is pinched in a notch in the shoulder blade and there is pain in the shoulder and a weakening external rotation and abduction. These limescale deposits can lead to a so-called impingement syndrome: This clinical picture involves pinching or pinching the tendon of the supraspinatus muscle under the shoulder roof. He has the most common injury of all rotator cuff muscles, especially since his tendon often shows calcifications as he ages. It is innervated by the suprascapular nerve. He also contributes less to the external rotation of the arm and also tensions the joint capsule. He shares this function with the deltoid muscle. 15 ° abduction, it is the "abduction starter".
Its function is that of the side arm lift (abduction), especially in the start phase of the movement up to approx. "Supra": above, "spina": spine) arises from the upper part of the back surface of the shoulder blade in the supraspinous fossa and extends under the shoulder roof to the majestic tubercle on the humerus. It is innervated by the subscapular nerve. Like all muscles of the rotator cuff, it also contributes to the tension of the joint capsule. It also supports the movement of the arm forwards (anteversion) and backwards (retroversion). Functionally, it serves to rotate the arm inwards (inner rotation), and is even the strongest inner rotator on the upper arm. The subscapularis muscle (Latin “sub”: under, “scapula”: shoulder blade) arises from the front of the shoulder blade in the subscapular fossa and attaches to the front of the humerus on the tubercle minus. A rotator cuff is a functionally important group of muscles of the shoulder joint that originates from the shoulder blade (scapula) and that wraps around the upper arm head like a cuff and is jointly responsible for the rotation (rotation) and lifting of the arm.Ī distinction is made with the rotator cuff