Brachialis
Origin: Anterior surface of distal half of humerus
Insertion: Ulnar tuberosity and coronoid process of ulna
Action: Elbow flexion
Innervation: Musculocutaneous nerve (C5, C6)
Triceps Brachii
Origin:
Long head: Infraglenoid tubercle of scapula
Lateral head: Inferior to greater tubercle on posterior humerus
Medial head: Posterior surface of humerus
Insertion: Olecranon process of ulna
Action: Shoulder extension, elbow extension
Innervation: Radial nerve (C6, C7, C8)
Supinator
Origin: Lateral epicondyle of humerus and adjacent ulna
Insertion: Anterior surface of the proximal radius
Action: Forearm supination, elbow flexion
Innervation: Radial nerve (C6)
Brachioradialis
Origin: Lateral supracondylar ridge on humerus
Insertion: Distal lateral aspect of the radius
Action: Elbow flexion, forearm supination and pronation
Innervation: Radial nerve (C5, C6)
Pronator Teres
Origin: Medial epicondyle of humerus and coronoid process of ulna
Insertion: Lateral aspect of radius at its midpoint
Action: Forearm pronation, elbow flexion
Innervation: Median nerve (C6, C7)
Pronator Quadratus
Origin: Anterior distal one-fourth of ulna
Insertion: Anterior distal one-fourth of radius
Action: Forearm pronation
Innervation: Median nerve (C8, T1)
Biceps Brachii
Origin:
Long head: Supraglenoid tubercle of scapula
Short head: Coracoid process of scapula
Insertion: Radial tuberosity of radius
Action: Shoulder flexion, elbow flexion, forearm supination
Innervation: Musculocutaneous nerve (C5, C6)
Anconeus
Origin: Lateral epicondyle of humerus
Insertion: Lateral and inferior to triceps on the olecranon process
Action: Elbow extension
Innervation: Radial nerve (C6, C7, C8)
Flexor Carpi Ulnaris
Origin: Medial epicondyle of humerus via common flexor tendon
Insertion: Pisiform and base of 5th metacarpal
Action: Combined wrist flexion and ulnar deviation
Innervation: Ulnar nerve (C8, T1)
Flexor Carpi Radialis
Origin: Medial epicondyle of humerus via common flexor tendon
Insertion: Base of 2nd and 3rd metacarpals
Action: Combined wrist flexion and radial deviation
Innervation: Median nerve (C6, C7)
Palmaris Longus
Origin: Medial epicondyle of humerus (via common flexor tendon)
Insertion: Palmar aponeurosis
Action: Wrist flexion
Innervation: Median nerve (C6, C7)
Extensor Carpi Radialis Longus
Origin: Lateral supracondylar ridge of humerus
Insertion: Base of 2nd metacarpal
Action: Combined wrist extension and radial deviation
Innervation: Radial nerve (C6, C7)
Extensor Carpi Radialis Brevis
Origin: Lateral epicondyle of humerus via common extensor tendon
Insertion: Base of 3rd metacarpal
Action: Wrist extension
Innervation: Radial nerve (C6, C7)
Extensor Carpi Ulnaris
Origin: Lateral epicondyle of humerus via common extensor tendon
Insertion: Base of 5th metacarpal
Action: Combined wrist extension and ulnar deviation
Innervation: Radial nerve (C6, C7, C8)
Flexor Digitorum Superficialis
Origin: Common flexor tendon, medial epicondyle, coronoid process and radius
Insertion: Side of the middle phalanx of the four fingers
Action: Wrist flexion, MCP and PIP flexion
Innervation: Median nerve (C7, C8, T1)
Flexor Digitorum Profundus
Origin: Coronoid process and proximal three-fourths of the ulna
Insertion: Distal phalanx of the four fingers
Action: Flexes all 3 joints of the fingers (DIPs, PIPs, and MCPs): wrist flexion
Innervation: Median and ulnar nerves (C8, T1)
Flexor Pollicis Longus
Origin: Anterior surface of radius, interosseous membrane
Insertion: Distal phalanx of thumb
Action: Flexes CMC, MCP and IP joints of thumb
Innervation: Median nerve (C8, T1)
Abductor Pollicis Longus
Origin: Posterior middle portions of radius, ulna, and interosseous membrane
Insertion: Base of the first (thumb) metacarpal
Action: Abducts CMC joint of the thumb; extends CMC and MCP joints of thumb
Innervation: Radial nerve (C6, C7)
Extensor Pollicis Brevis
Origin: Posterior distal radius and interosseous membrane
Insertion: Base of the proximal phalanx of thumb
Action: Extends MCP and CMC joints of thumb
Innervation: Radial nerve (C6, C7)
Extensor Pollicis Longus
Origin: Posterior middle portions of ulna and interosseous membrane
Insertion: Base of distal phalanx of thumb
Action: Extends the CMC, MCP, and IP joints of the thumb
Innervation: Radial nerve (C6, C7, C8)
Extensor Digitorum
Origin: Lateral epicondyle of humerus
Insertion: Base of distal phalanx of the 2nd through 5th fingers
Action: Extends wrist, extends MCP, PIP, and DIP joints of the four fingers
Innervation: Radial nerve (C6, C7, C8)
Extensor Indicis
Origin: Distal ulna
Insertion: Base of distal phalanx of 2nd finger
Action: Extends all three joints of the second finger (DIP, PIP, MCP)
Innervation: Radial nerve (C6, C7, C8)
Extensor Digiti Minimi
Origin: Lateral epicondyle of humerus via common extensor tendon
Insertion: Base of distal phalanx of little finger
Action: Extends all MCP, PIP and DIP joints of little finger
Innervation: Radial nerve (C6, C7, C8)
Flexor Pollicis Brevis
Origin: Trapezium and flexor retinaculum
Insertion: Proximal phalanx of the thumb
Action: Flexes the MCP and CMC joints of thumb
Innervation: Median nerve (C6, C7)
Abductor Pollicis Brevis
Origin: Scaphoid, trapezium, and flexor retinaculum
Insertion: Proximal phalanx of the thumb
Action: Abducts the thumb (CMC joint)
Innervation: Median nerve (C6, C7)
Opponens Pollicis
Origin: Trapezium and flexor retinaculum
Insertion: First metacarpal
Action: Thumb opposition (CMC)
Innervation: Median nerve (C6, C7)
Flexor Digiti Minimi
Origin: Hamate and flexor retinaculum
Insertion: Base of proximal phalanx of the fifth finger
Action: Flexes MCP and CMC joints of the fifth finger
Innervation: Ulnar nerve (C8, T1)
Opponens Digiti Minimi
Origin: Hamate and flexor retinaculum
Insertion: 5th metacarpal
Action: Opposes little finger (CMC joint)
Innervation: Ulnar nerve (C8, T1)
Abductor Digiti Minimi
Origin: Pisiform and tendon of flexor carpi ulnaris
Insertion: Proximal phalanx of little finger
Action: Abducts the MCP joint of the little finger
Innervation: Ulnar nerve (C8, T1)
Adductor Pollicis
Origin: Capitate, bases of 2nd and 3rd metacarpals, and distal two-thirds of the palmar surface of the 3rd metacarpal
Insertion: Base of proximal phalanx of thumb
Action: Adducts thumb (CMC joint)
Innervation: Ulnar nerve (C8, T1)
Dorsal Interossei
Origin: Adjacent metacarpals
Insertion: Base of proximal phalanges of index, middle, and ring fingers
Action: Abduct fingers at MCP joint
Innervation: Ulnar nerve (C8, T1)
Palmar Interossei
Origin: 2nd, 4th, and 5th metacarpals
Insertion: Base of respective proximal phalanx
Action: Adduct index, ring, and middle fingers at MCP joint
Innervation: Ulnar nerve (C8, T1)
Lumbricals
Origin: Tendon of the flexor digitorum profundus muscle
Insertion: Tendon of the extensor digitorum muscle
Action: Simultaneous flexion of the MCP and extension of the PIP and DIP joints of each of the four fingers.