The muscles that act on the elbow joint primarily function to flex and extend the forearm, enabling movement at this critical articulation.
Here's a breakdown of the major elbow muscles, detailing their origin, insertion, and action:
Elbow Flexors
These muscles are responsible for bending the elbow.
| Muscle | Origin | Insertion | Action |
|---|---|---|---|
| Biceps Brachii | Short head: Coracoid process of the scapula; Long head: Supraglenoid tubercle of the scapula | Radial tuberosity and bicipital aponeurosis into deep fascia of forearm | Flexion of elbow; supination of forearm; weak shoulder flexion |
| Brachialis | Distal anterior humerus | Ulnar tuberosity | Primary flexor of elbow (pure flexion) |
| Brachioradialis | Lateral supracondylar ridge of humerus | Styloid process of radius | Flexion of elbow (especially when forearm is mid-pronated/supinated); assists in pronation and supination to the neutral position. |
Elbow Extensors
These muscles straighten the elbow.
| Muscle | Origin | Insertion | Action |
|---|---|---|---|
| Triceps Brachii | Long head: Infraglenoid tubercle of the scapula; Lateral head: Humerus, superior to radial groove; Medial head: Humerus, inferior to radial groove | Olecranon process of ulna | Primary elbow extensor; long head assists with shoulder extension and adduction |
| Anconeus | Lateral epicondyle of humerus | Olecranon process of ulna | Assists triceps brachii in elbow extension |
Summary: The elbow muscles, including the biceps brachii, brachialis, brachioradialis, triceps brachii, and anconeus, work together to provide flexion and extension at the elbow joint. Each muscle has specific origins and insertions that dictate its precise action and contribution to overall arm movement.
