OIAs of upper arm and forearm

Biceps brachii

O - Short head: tip of the coracoid process of scapula

Long head: supraglenoid tubercle of scapula

I - Tuberosity of radius and fascia of forearm via bicipital aponeurosis

A - Supinates forearm and, when it is supinated, flexes elbow joint; flexes shoulder joint; short head resists dislocation of shoulder.

Innervation - Musculocutaneous nerveb (C5, C6)

Brachialis

O - Distal half of anterior surface of humerus

I - Coronoid process and tuberosity of ulna

A - Flexes elbow joint in all positions

Innervation - Musculocutaneous nerveb (C5, C6)

Coracobrachialis

O - Tip of coracoid process of scapula

I - Middle third of medial surface of humerus

A - Helps flex and adduct shoulder joint; resists dislocation of shoulder

Innervation - Musculocutaneous nerve (C5, C6, C7)

Triceps brachii

O - Long head: infraglenoid tubercle of scapula

Lateral head: posterior surface of humerus, superior to radial groove

Medial head: posterior surface of humerus, inferior to radial groove

I - Proximal end of olecranon of ulna and fascia of forearm

A - Chief extensor of elbow joint; long head extends shoulder joint and resists dislocation of humerus (especially important during abduction).

Innervation - Radial nerve (C6, C7, C8)

Anconeus

O - Lateral epicondyle of humerus

I - Lateral surface of olecranon and superior part of posterior surface of ulna

A - Assists triceps in extending elbow joint; stabilizes elbow joint; abducts ulna during pronation

Pronator teres (PT), Ulnar head, Humeral head

O - Coronoid process of ulna, Medial epicondyle of humerus

I - Middle of convexity of lateral surface of radius

A - Pronates forearm and flexes elbow joint

Innervation - Median nerve (C6, C7)

Flexor carpi radialis (FCR)

O - Medial epicondyle of humerus

I - Base of 2nd (3rd) metacarpal

A - Flexes and abducts hand at wrist

Innervation - Median nerve (C6, C7)

Palmaris longus

O - Medial epicondyle of humerus

I - Distal half of flexor retinaculum, palmar aponeurosis

A - Flexes hand (at wrist) and tenses palmar aponeurosis

Innervation - Median nerve (C7, C8)

Flexor carpi ulnaris (FCU), Humeral head, Ulnar head

O - Olecranon and posterior border of ulna (via aponeurosis)

I - Pisiform, hook of hamate, 5th metacarpal

A - Flexes and adducts hand at wrist

Innervation - Ulnar nerve (C7, C8)

Flexor digitorum superficialis (FDS)

O - Humeroulnar head: medial epicondyle of humerus and coronoid process of ulna

Radial head: oblique line of radius

I - Shafts (bodies) of middle phalanges of medial four digits

A - Flexes wrist joint, carpometacarpal joints. Flexes proximal interphalangeal joints of middle four digits; acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints.

Innervation - Median nerve (C7, C8, T1)

Flexor digitorum profundus (FDP)

O - Proximal three quarters of medial and anterior surfaces of ulna and

interosseous membrane

I - Bases of distal phalanges of 2nd, 3rd, 4th, and 5th digits

A - Flexes wrist joint, carpometacarpal joints

Flexes distal interphalangeal joints of digits 2, 3, 4, and 5; assists with wrist flexion

Innervation - Lateral part (to digits 2 and 3): median nerve (C8, T1)

(anterior interosseous branch)

Medial part (to digits 4 and 5): ulnar nerve (C8, T1)

Flexor pollicis longus (FPL)

O - Anterior surface of radius and adjacent interosseous membrane

I - Base of distal phalanx of thumb

A - Flexes wrist joint, carpometacarpal joints

Flexes metacarpophalangeal and interphalangeal joints of thumb

Innervation - Anterior interosseous nerve, from median nerve (C8, T1)

Pronator quadratus

O - Distal quarter of anterior surface of ulna

I - Distal quarter of anterior surface of radius

A - Pronates forearm; deep fibers bind radius and ulna together.

Innervation - Anterior interosseous nerve, from median nerve (C8, T1)