Kinesiology

Lesson 11 of 16

Arm and elbow

The elbow region includes the humeroulnar and humeroradial joints as well as the proximal radioulnar joint. Muscles crossing the elbow can flex or extend it, while some also act on the shoulder or forearm. The biceps and brachialis are prominent flexors; the triceps is the principal extensor. Support the arm to avoid unnecessary strain during treatment.

Key points

• Biceps brachii flexes the elbow and supinates the forearm; its shoulder contribution depends on position.
• Brachialis is a strong elbow flexor across forearm positions.
• Triceps brachii extends the elbow; its long head also crosses the shoulder.
• Brachioradialis assists elbow flexion, especially with the forearm near neutral.
• Do not infer tendon injury from tenderness; ask about symptoms and refer when appropriate.
• Keep the limb supported and avoid sustained end-range elbow positions.

Key terms

Biceps brachii

O: supraglenoid tubercle and coracoid process; I: radial tuberosity and bicipital aponeurosis; A: flexes elbow and supinates forearm.

Brachialis

O: anterior distal humerus; I: ulnar tuberosity and coronoid process; A: flexes elbow.

Triceps brachii

O: infraglenoid tubercle and posterior humerus; I: olecranon; A: extends elbow; long head assists shoulder extension/adduction.

Brachioradialis

O: lateral supracondylar ridge; I: distal radius near styloid; A: flexes elbow, strongest near neutral forearm.

Anconeus

O: lateral epicondyle; I: olecranon and proximal posterior ulna; A: assists elbow extension and stabilizes elbow.