Upper Limb Muscles: Origins, Insertions, Actions & Innervations

Vocabulary flashcards summarizing the origin, insertion, action, and innervation of key forearm and arm muscles.

Biceps brachii

Origin: Short head—coracoid process of scapula; Long head—supraglenoid tubercle of scapula. Insertion: Radial tuberosity. Actions: Elbow flexion; Forearm supination. Nerve: Musculocutaneous.

Brachialis

Origin: Distal anterior surface of humerus. Insertion: Coronoid process of ulna. Action: Elbow flexion (strongest with forearm pronated). Nerve: Musculocutaneous.

Brachioradialis

Origin: Lateral supracondylar ridge of humerus. Insertion: Styloid process of radius. Action: Brings forearm to neutral from pronation or supination (flexes elbow in neutral). Nerve: Radial.

Triceps brachii

Origin: Lateral & medial heads—posterior shaft of humerus; Long head—infraglenoid tubercle of scapula. Insertion: Olecranon process of ulna. Actions: Elbow extension (all heads); Shoulder extension (long head). Nerve: Radial.

Supinator

Origin: Posterolateral distal humerus & posterior proximal ulna. Insertion: Anterior proximal radius. Action: Forearm supination. Nerve: Radial.

Pronator teres

Origin: Medial epicondyle of humerus. Insertion: Mid lateral surface of radius. Action: Forearm pronation. Nerve: Median.

Pronator quadratus

Origin: Distal anterior ulna. Insertion: Distal anterior radius. Action: Forearm pronation. Nerve: Median.