The anconeus muscle (m.anconeus) has a triangular shape, originates on the posterior surface of the lateral epicondyle of the humerus; attaches to the lateral surface of the olecranon, the posterior surface of the proximal part of the ulna and to the fascia of the forearm.
The triceps brachii is thick, occupies the entire back surface of the shoulder, and has three heads. The lateral and medial heads originate on the humerus, and the long head originates on the scapula.
The brachialis muscle (m.brachialis) originates on the lower two-thirds of the body of the humerus between the deltoid tuberosity and the joint capsule of the elbow joint, on the medial and lateral intermuscular septa of the shoulder.
The coracobrachialis muscle (m.coracobrachialis) begins at the apex of the coracoid process of the scapula, passes into a flat tendon, which is attached to the humerus below the crest of the lesser tubercle at the level of attachment of the deltoid tendon.
The shoulder muscles are divided into two groups according to the topographic-anatomical principle - anterior (flexors) and posterior (extensors). The anterior group consists of three muscles: coracobrachialis, biceps brachii and brachialis; the posterior group - triceps brachii and ulnaris.
The subscapularis muscle (m. subscapularis) is wide, thick, triangular in shape. It occupies almost the entire costal surface of the scapula. It has a fleshy origin on the surface of the subscapular fossa and the lateral edge of the scapula.
The small teres muscle (m.terpes minor) originates on the lateral edge of the scapula and the infraspinatus fascia; it is attached to the lower surface of the greater tubercle of the humerus.
The supraspinatus muscle (m.supraspinatus) is located in the supraspinatus fossa. It begins on the back surface of the scapula above the scapular spine and on the supraspinatus fascia. The bundles pass in the lateral direction.
The deltoid muscle (m.deltoideus) is located superficially, directly under the skin, covers the shoulder joint from the lateral side, from the front, from above and from behind, and forms the characteristic roundness of the shoulder).
