Part 2

• Intrinsic muscles of the shoulder

  • Deltoideus
  • Infraspinatus
  • Teres minor
  • Supraspinatus
  • Subscapularis
  • Teres major
  • Coracobrachialis
• Deltoideus


  Origin: The spine and acromial process of the scapula

  Insertion: The deltoid tuberosity

  Action: To flex the shoulder

  Innervation: Axillary nerve
• Infraspinatus


  Origin: The infraspinous fossa

  Insertion: A small, circumscribed area on the lateral side of the greater tubercle of the humerus

  Action: To extend or flex the joint, depending on the degree of extension or position of the joint when the muscle contracts. To abduct the shoulder and to rotate the arm laterally

  Innervation: Suprascapular nerve
• Teres minor


  Origin: The infragleonoid tubercle and distal third of the caudal border of the scapula

  Insertion: The teres minor tuberosity of the humerus

  Action: To flex the shoulder and rotate the arm laterally

  Innervation: Axillary nerve
• Supraspinatus


  Origin: The supaspinous fossa

  Insertion: The greater tubercle of the humerus, by a thick tendon

  Action: To extend the shoulder

  Innervation: Suprascapular nerve
• Subscapularis


  Origin: The subscapular fossa

  Insertion: The lesser tubercle of the humerus

  Action: To adduct and extend the shoulder

  Innervation: Subscapular nerve
• Teres major


  Origin: The caudal angle and adjacent border of the scapula; the caudal surface of the subscapularis

  Insertion: The teres major tuberosity of the humerus

  Action: Flex the shoulder and rotate the arm medially

  Innervation: Axillary nerve
• Coracobrachialis


  Origin: The coracoid process of the scapula

  Insertion: The crest of the lesser tubercle of the humerus proximal to the teres major tuberosity

  Action: To adduct and extend the shoulder

  Innervation: Musculocutaneous nerve
• Muscles of the forearm

  • Tensor fascia antebrachii
  • Triceps brachii
  • Anconeus
  • Biceps brachii
  • Brachialis
  • Extensor carpi radialis
  • Common digital extensor
  • Lateral digital extensor
  • Ulnaris lateralis
  • Supinator
  • Pronator teres
  • Abductor pollicis longus
  • Flexor carpi radialis
  • Superficial digital flexor
  • Flexor carpi ulnaris
  • Deep digital flexor
  • Pronator quadratus
• Tensor fascia antebrachii


  Origin: The fascia covering the lateral side of the latissimus dorsi

  Insertion: The olecranon

  Action: To extend the elbow

  Innervation: Radial nerve
• Triceps brachii - Long head


  Origin: the caudal border of the scapula

  Insertion: The olecranon

  Action: To extend the elbow and flex the shoulder

  Innervation: Radial nerve
• Triceps brachii - Lateral head


  Origin: laterally on humerus; crest of the greater tubercle of the humerus

  Insertion: The olecranon

  Action: To extend the elbow

  Innervation: Radial nerve
• Triceps brachii - Medial head


  Origin: medially on humerus; caudal tuberosity of teres major, crest of the lesser tubercle

  Insertion: The olecranon

  Action: To extend the elbow

  Innervation: Radial nerve
• Triceps brachii - Accessory head


  Origin: The neck of the humerus

  Insertion: The olecranon

  Action: To extend the elbow

  Innervation: Radial nerve
• Anconeus


  Origin: The lateral epicondylar crest and the lateral and medial epicondyles of the humerus

  Insertion: The lateral surface of the proximal end of the ulna

  Action: To extend the elbow

  Innervation: Radial nerve
• Biceps brachii


  Origin: The supraglenoid tubercle

  Insertion: The ulnar and radial tuberosities

  Action: To flex the elbow and extend the shoulder

  Innervation: Musculocutaneous nerve
• Brachialis


  Origin: The proximal third of the lateral surface of the humerus

  Insertion: The ulnar and radial tuberosities

  Action: To flex the elbow

  Innervation: Musculocutaneous nerve
• Extensor carpi radialis


  Origin: The lateral epicondylar crest

  Insertion: The small tuberosities on the proximal ends and dorsal surfaces of metacarpals II and III

  Action: To extend the carpus

  Innervation: Radial nerve
• Common digital extensor


  Origin: The lateral epicondyle of the humerus

  Insertion: The extensor processes of the distal phalanges of digits II, III, IV and V

  Action: To extend the joints of the 4 principal digits

  Innervation: Radial nerve
• Lateral digital extensor


  Origin: The lateral epicondyle of the humerus

  Insertion: The proximal ends of all phalanges of digits III, IV, and V, but mainly the extensor processes of the distal phalanges of these digits

  Action: To extend the joints of digits III, IV, and V

  Innervation: Radial nerve
• Ulnaris lateralis


  Origin: the lateral epicondyle of the humerus

  Insertion: the lateral aspect of the proximal end of metacarpal V and the accessory carpal bone

  Action: To abduct and flex the carpus

  Innervation: Radial nerve
• Supinator


  Origin: The lateral epicondyle of the humerus

  Insertion: The crania; surface of the proximal fourth of the radius

  Action: To rotate the forearm laterally so that the palmar side of the paw faces medially (supination), and to flex the elbow

  Innervation: Radial nerve
• Pronator teres


  Origin: The medial epicondyle of the humerus

  Insertion: The medial border of the radius between the proximal and middle thirds

  Action: To rotate the forearm medially so that the palmar side of the paw faces the ground (pronation); to flex the elbow

  Innervation: Median nerve
• Abductor pollicis longus


  Origin: The lateral border and cranial surface of the body of the ulna; the interosseous membrane

  Insertion: The proximal end of metacarpal I

  Action: To abduct the first digit or pollex

  Innervation: Radial nerve
• Flexor carpi radialis


  Origin: The medial epicondyle of the humerus and the medial border of the radius

  Insertion: The palmar side of the proximal ends of metacarpals II and III

  Action: To flex the carpus

  Innervation: Median nerve
• Superficial digital flexor


  Origin: The medial epicondyle of the humerus

  Insertion: The palmar surface of the base (proximal end) of the middle phalanges of digits II, III, IV and V

  Action: To flex digits II, III, IV and V

  Innervation: Median nerve
• Flexor carpi ulnaris


  Origin: Ulnar head – the caudal border and medial surface of the olecranon; humeral head – the medial epicondyle of the humerus

  Insertion: the accessory carpal bone

  Action: to flex the carpus

  Innervation: ulnar nerve
• Deep digital flexor


  Origin: Humeral head – the medial epicondyle of the humerus, Ulnar head – the proximal three-fourths of the caudal border of the ulna, Radial head – the middle third of the medial border of the radius

  Insertion: the palmar surface of the base (proximal end) of the distal phalanx of each digit

  Action: to flex the digit

  Innervation: median and ulnar nerves
• Pronator quadratus


  Attachments: the apposed surfaces of the radius and the ulna

  Action: to pronate the paw

  Innervation: median nerve