Shoulder muscles

The shoulder muscles are the muscles with which the shoulder girdle and shoulder joint are moved. It also stabilizes the very flexible shoulder joint, which is only weakly secured by ligaments, and fixes the shoulder girdle and thus the upper extremity to the trunk. The shoulder muscles can be divided into the muscles used to move the shoulder girdle and the muscles used to move the upper arm.

The shoulder muscles control the rotational movements of an arm, for example in baseball , handball , volleyball and other manual ball games, as well as when using a racket . It also supports the back muscles .

Muscles for moving the shoulder girdle

The shoulder girdle muscles connect the shoulder girdle to the trunk and enable movement of the same. The shoulder girdle consists of the collarbone (clavicle), shoulder blade (scapula) and the clavicle joints , the sternoclavicular joint and the acromioclavicular joint . Since the arm is suspended from the shoulder blade in the shoulder joint, the range of motion of the upper extremity is increased considerably by the mobility of the shoulder girdle.

The shoulder girdle muscles can be divided into two groups: the dorsal group (also called spinoscapular muscles) and the ventral group. The dorsal group consists of the trapezius muscle , muscle rhomboideus major and minor and levator scapula . The ventral group consists of serratus anterior muscle , pectoralis minor and muscle subclavius together.

Muscles that move the upper arm

The shoulder muscles in the narrower sense include the muscles that arise from the trunk and shoulder blade and attach to the upper arm and move it. It is part of the upper limb's own muscles. It can be divided into two groups, the rotator cuff and the other shoulder muscles. The rotator cuff is formed by the following four muscles:

• Subscapularis muscle
• Supraspinatus muscle
• Infraspinatus muscle
• Teres minor muscle

These muscles significantly stabilize the very mobile shoulder joint and prevent dislocation . The muscles arise from the shoulder blade and radiate into the joint capsule of the shoulder joint in the shape of a cuff , thereby strengthening the capsule. The rotator cuff muscles are functionally important for external and internal rotation (M. subscapularis and M. infraspinatus). The supraspinatus muscle gains clinical relevance in impingement syndrome , a common disease in which the supraspinatus tendon is pinched between the acromion and humeral head during abduction (physiology) of the upper arm and is thereby damaged. This can result in inflammation and also rupture of the tendon. The other shoulder muscles perform movements in the shoulder joint:

• Latissimus dorsi muscle
• Deltoid muscle
• Teres major muscle
• Coracobrachialis muscle

literature

D. Drenckhahn and J. Waschke: Taschenbuch Anatomie Benninghoff / Drenckhahn. 2nd edition, Elsevier GmbH, Munich 2014.