The elbow muscles are a group of muscles that cross the elbow joint, enabling flexion, extension, pronation, and supination of the forearm. Their origin and insertion points define their function.
Here's a breakdown of key elbow muscles, including their origins and insertions:
Biceps Brachii
- Action: Primarily flexes the elbow and supinates the forearm.
- Origin:
- Long head: Supraglenoid tubercle of the scapula.
- Short head: Coracoid process of the scapula.
- Insertion: Radial tuberosity of the radius.
Brachialis
- Action: Powerful elbow flexor.
- Origin: Anterior surface of the distal humerus.
- Insertion: Ulnar tuberosity and coronoid process of the ulna.
Brachioradialis
- Action: Flexes the elbow, pronates the forearm from a supinated position, and supinates the forearm from a pronated position.
- Origin: Proximal two-thirds of the lateral supracondylar ridge of the humerus.
- Insertion: Styloid process of the radius.
Triceps Brachii
- Action: Elbow extension.
- Origin:
- Long head: Infraglenoid tubercle of the scapula.
- Lateral head: Posterior humerus, superior to the radial groove.
- Medial head: Posterior humerus, inferior to the radial groove.
- Insertion: Olecranon process of the ulna.
Anconeus
- Action: Assists the triceps brachii in elbow extension and stabilizes the elbow joint.
- Origin: Lateral epicondyle of the humerus.
- Insertion: Olecranon process and superior posterior ulna.
Pronator Teres
- Action: Pronates the forearm and assists in elbow flexion.
- Origin:
- Humeral head: Medial epicondyle of the humerus.
- Ulnar head: Coronoid process of the ulna.
- Insertion: Lateral surface of the radius at its midpoint.
Pronator Quadratus
- Action: Pronates the forearm.
- Origin: Distal anterior ulna.
- Insertion: Distal anterior radius.
Supinator
- Action: Supinates the forearm.
- Origin: Lateral epicondyle of the humerus, radial collateral ligament, annular ligament, and supinator crest of the ulna.
- Insertion: Lateral surface of the proximal radius.
In summary, the elbow muscles act across the elbow joint, with their functions (flexion, extension, pronation, supination) dictated by their origin and insertion points on the humerus, radius, and ulna, as well as their relationship to the joint axis.
