Elbow and hand overview muscles edited

Page 1: Muscle Actions and Innervations

• 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)

Page 2: Additional Muscle Functions

• 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)

Page 3: Arm Muscles

• 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)

Page 4: Wrist Flexors

• 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)

Page 5: Wrist Extensors

• 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)

Page 6: Flexor Muscles of Hand

• 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)

Page 7: Thumb Flexors and Abductors

• 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)

Page 8: Thumb Extensors

• 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)

Page 9: Little Finger and Intrinsic Hand Muscles

• 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)

Page 10: Hypothenar Functions

• 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)

Page 11: Deep Palmar Intrinsics

• 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)

Page 12: Lumbricals

• 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.