Elbow and Radio-ulnar joints - OIAI

Pronator quadratus

O: Distal fourth of the ulna

I: Distal fourth of the radius

A: Pronation

I: Median nerve

Pronator teres

O: Medial epicondyle of the humerus

I: lateral surface of radius

A: Pronation and flexion

I: Median nerve

Supinator

O: Lateral epicondyle of humerus, RCL, annular ligament, superior crest of ulna

I: Lateral, anterior, and posterior surfaces of the proximal third of radius

A: Supination

I: Radial nerve

Biceps brachii short head

O: Coracoid process of scapula

I: Radial tuberosity of the radius

A: Flexion at the shoulder joint; Flexion at the elbow joint

I: Musculocutaneous nerve

Brachioradialis

O: Lateral supracondylar ridge of the humerus

I: Styloid process of the radius

A: Flexion at the elbow joint

I: Radial nerve

Brachialis

O: Anterior distal half of humerus

I: Coronoid process of the ulna

A: Flexion at the elbow joint

I: Musculocutaneous nerve

Triceps brachii medial head

O: Posterior body of humerus

I: Olecranon process of the ulna

A: Extension at the elbow joint

I: Radial nerve

Triceps brachii long head

O: Infraglenoid tubercle of scapula

I: Olecranon process of the ulna

A: Extension at the elbow joint, Extension, and adduction at the shoulder joint

I: Radial nerve

Triceps brachii lateral head

O: Posterior body of humerus

I: Olecranon process of the ulna

A: Extension at the elbow joint

I: Radial nerve